This page describes the history of the 737 MAX Maneuvering Characteristics Augmentation System (MCAS), the changes to it and associated systems and procedures during the MAX grounding.
MCAS is a longitudinal stability enhancement. It is not for stall prevention (although indirectly it helps) or to make the MAX handle like the NG (although it does); it was introduced to counteract the non-linear lift generated by the LEAP-1B engine nacelles at high AoA and give a steady increase in stick force as the stall is approached as required by regulation.
The LEAP engine nacelles are larger and had to be mounted slightly higher and further forward from the previous NG CFM56-7 engines to give the necessary ground clearance. This new location and larger size of nacelle cause the vortex flow off the nacelle body to produce lift at high AoA. As the nacelle is ahead of the C of G, this lift causes a slight pitch-up effect (ie a reducing stick force) which could lead the pilot to inadvertently pull the yoke further aft than intended bringing the aircraft closer towards the stall. This abnormal nose-up pitching is not allowable under 14CFR §25.203(a) "Stall characteristics". Several aerodynamic solutions were introduced such as revising the leading edge stall strip and modifying the leading edge vortilons but they were insufficient to pass regulation. MCAS was therefore introduced to give an automatic nose down stabilizer input during elevated AoA when flaps are up.
On the face of it, MCAS seemed like a reasonable solution to the low speed handling certification problem. However, two accidents occurred to the MAX which were attributed to MCAS - Lion Air MAX-8 PK-LQP on 29 October 2018 and Ethiopian MAX-8 ET-AVJ on 10 March 2019, both of which crashed shortly after take-off following erroneous data from a single AoA probe. MCAS used this erroneous AoA data to command nose down stabiliser trim which was not counteracted successfully by the crew until impact.
The MCAS design at the time of these accidents would trim the Stabilizer down for up to 9.26 seconds (2.5 deg nose down) then pause for 5 seconds and repeat if the conditions (high AoA, flaps up and autopilot disengaged) continued to be met. If the pilots used electric pitch trim, it would only pause MCAS for 5s; to deactivate it you have to switch off the STAB TRIM CUTOUT switches.
As details emerged about the similarities between the two accidents, the 737 MAX was grounded by many countries unilaterally. The FAA followed suit on 13 March. Boeing issued the following statement: “After consultation with the US FAA, the US NTSB, and aviation authorities and its customers around the world, Boeing has determined—out of an abundance of caution and in order to reassure the flying public of the aircraft’s safety—to recommend to the FAA the temporary suspension of operations of the entire global fleet of 371 737 MAX aircraft. Boeing makes this recommendation and supports the decision by the FAA.”.
The MAX was finally ungrounded on 18 Nov 2020 by the FAA. The events cost Boeing over $21 billion in direct costs - $8.6B in compensation to customers for having their aircraft grounded, $5B for unusual costs of production, $6.3B for increased costs of the 737 Max program, $600M for aircraft storage, pilot training and software updates, an estimated $500M settlements to victims families. There was also an eyewatering estimated $67B in lost sales (around 1200 aircraft).
14CFR §25.203 Stall characteristics.
(a) It must be possible to produce and to correct roll and yaw by unreversed use of the aileron and rudder controls, up to the time the airplane is stalled. No abnormal nose-up pitching may occur. The longitudinal control force must be positive up to and throughout the stall. In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls.
Technical Description of MCAS (Pre-2019)
The original design of MCAS was that it would only activate "at extreme high speed pitch-up conditions that are outside the normal operating envelope" (see extract from the Mainenance Training Manual below). However during flight testing it became apparent that the engine nacelles were also creating a pitch-up effect under certain conditions at very low speeds. So the scope of MCAS was broadened to include low speed activation as well as high speed activation.
Above an extract from the MTM showing the original scope of MCAS was at high speed only
MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance longitudinal stability characteristics with flaps UP and at elevated Angles of Attack (AoA). The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall. MCAS is activated without pilot input and only operates in manual, flaps up flight. The system is designed to allow the flight crew to use column trim switch or stabilizer aislestand cutout switches to override MCAS input. The function is commanded by the Flight Control Computer (FCC) using input data from sensors and other airplane systems.
The MCAS function becomes active when the AoA exceeds a threshold based on airspeed and altitude. MCAS will activate for up to 9.26 seconds before pausing for 5 seconds. Stabilizer incremental commands are limited to 2.5 degrees and are provided at a rate of 0.27 degrees per second. The magnitude of the stabilizer input is lower at high Mach number and greater at low Mach numbers (for the same AoA above the activation threshold).
After AoA falls below the hysteresis threshold (0.5 degrees below the activation angle), MCAS commands nose up stabilizer to return the aircraft to the trim state that existed before the MCAS activation.
The function is reset once angle of attack falls below the Angle of Attack threshold or if manual stabilizer commands are provided by the flight crew. If the original elevated AOA condition persists, the MCAS function commands another incremental stabilizer nose down command according to current aircraft Mach number at actuation.
To summarise; MCAS will trim the Stabilizer down for up to 9.26 seconds (2.5 deg nose down) and pause for 5 seconds and repeat if the conditions (high angle of attack, flaps up and autopilot disengaged) continue to be met. MCAS will turn the trim wheel. Using electric pitch trim will only pause MCAS for 5s; to deactivate it you need to switch off the STAB TRIM CUTOUT switches.
The AoA source
Since MCAS is an FCC function, the AoA source for MCAS is that of the FCC in use; ie FCC 1 uses the Captains AoA probe and FCC 2 uses the F/Os AoA probe. When the 737 is powered up the FCC used is FCC 1 for that flight, this changes for each subsequent flight until the aircraft is powered down. Therefore the AOA sensor that is used for MCAS changes with each flight post power-up.
During The House Committee on Transportation & Infrastructure hearing in October 2019, an email exchange was disclosed between Boeing employees from 2015 which read: "Are we vulnerable to single AOA sensor failures with the MCAS implementation?" The response from CEO Dennis Muilenburg was that the email showed that "our engineers do raise questions, in an open culture," but that the single-sensor design met the standards. John Hamilton, chief engineer for Boeing’s commercial airplane division, who testified alongside Muilenburg, said that single points of failure are allowed in airplane design depending on the hazard assessment. Any dissent the committee could present on the final assessment that a single sensor was merited “highlights that our engineers do raise questions and it’s an open culture.”
The final KNKT investigation report into the Lion Air accident, said as a contributing factor "The replacement AOA sensor that was installed on the accident aircraft had been mis-calibrated during an earlier repair. This mis-calibration was not detected during the repair." the angle it registered was 21 degrees too high. Following publication of this report, the FAA revoked the certificate of approval of Xtra Aerospace of Miramar, Fla., the company that supplied the faulty AoA sensor. Xtra subsequently issued a statement saying that “we respectfully disagree with the agency’s findings.” It added that the revocation of its certificate “is not an indication that Xtra was responsible for the accident.”
The MAX probes on the LHS. The AoA vane is the bottom of the three probes.
AoA Display
Pre-accidents, there was an option for airlines to have an AoA indicator displayed on the PFDs - for a fee. As far as I know this option was only been taken by Southwest and American Airlines before the accidents. As part of the post-grounding MCAS upgrade, the optional AoA indicator will now be available free of charge and the AOA DISAGREE alert will now be standard on all MAX aircraft.
The AoA Disagree Alert will display "AOA DISAGREE" in amber at the bottom right of the PFD if the AoA vanes disagree by more than 10 degrees for more than 10 continuous seconds.
The QRH AoA Disagree Procedure is as follows:
Condition: The AOA DISAGREE alert indicates the left and right angle of attack vanes disagree.
1 Airspeed errors and the IAS DISAGREE alert may occur.
2 Altimeter errors and the ALT DISAGREE alert may occur.
Boeing has said in a statement on Monday 29 April that an error on their part meant that the AOA DISAGREE alert was only enabled on aircraft in which the customers had selected the optional AOA indicator. The alert was intended to be enabled on all MAX aircraft as standard.
“The disagree alert was intended to be a standard, stand-alone feature on Max airplanes,” the company said. “However, the disagree alert was not operable on all airplanes because the feature was not activated as intended.”
The error was discovered in 2017, Boeing says a Safety Review Board it had convened confirmed the company’s view that that the absence of a 737 AOA disagree alerts did not present a safety issue, and this was shared with the FAA.
Note that the MAX will have a software update (CDS BP?) to allow the disagree alert to function without relying on any optional systems as it does on the NG. This of course is in addition to the FCC update for MCAS.
This is the full statement:
"On every airplane delivered to our customers, including the MAX, all flight data and information needed to safely operate the aircraft is provided in the flight deck on the primary flight deck displays. This information is provided full-time in the pilots’ primary field of view, and it always has been.
Air speed, attitude, altitude, vertical speed, heading and engine power settings are the primary parameters the flight crews use to safely operate the airplane in normal flight. Stick shaker and the pitch limit indicator are the primary features used for the operation of the airplane at elevated angles of attack. All recommended pilot actions, checklists, and training are based upon these primary indicators. Neither the angle of attack indicator nor the AOA Disagree alert are necessary for the safe operation of the airplane. They provide supplemental information only, and have never been considered safety features on commercial jet transport airplanes.
The Boeing design requirements for the 737 MAX included the AOA Disagree alert as a standard, standalone feature, in keeping with Boeing’s fundamental design philosophy of retaining commonality with the 737NG. In 2017, within several months after beginning 737 MAX deliveries, engineers at Boeing identified that the 737 MAX display system software did not correctly meet the AOA Disagree alert requirements. The software delivered to Boeing linked the AOA Disagree alert to the AOA indicator, which is an optional feature on the MAX and the NG. Accordingly, the software activated the AOA Disagree alert only if an airline opted for the AOA indicator.
When the discrepancy between the requirements and the software was identified, Boeing followed its standard process for determining the appropriate resolution of such issues. That review, which involved multiple company subject matter experts, determined that the absence of the AOA Disagree alert did not adversely impact airplane safety or operation. Accordingly, the review concluded, the existing functionality was acceptable until the alert and the indicator could be delinked in the next planned display system software update. Senior company leadership was not involved in the review and first became aware of this issue in the aftermath of the Lion Air accident.
Approximately a week after the Lion Air accident, on November 6, 2018, Boeing issued an Operations Manual Bulletin (OMB), which was followed a day later by the FAA’s issuance of an Airworthiness Directive (AD). In identifying the AOA Disagree alert as one among a number of indications that could result from erroneous AOA, both the OMB and the AD described the AOA Disagree alert feature as available only if the AOA indicator option is installed.
Boeing discussed the status of the AOA Disagree alert with the FAA in the wake of the Lion Air accident. At that time, Boeing informed the FAA that Boeing engineers had identified the software issue in 2017 and had determined per Boeing’s standard process that the issue did not adversely impact airplane safety or operation. In December 2018, Boeing convened a Safety Review Board (SRB) to consider again whether the absence of the AOA Disagree alert from certain 737 MAX flight displays presented a safety issue. That SRB confirmed Boeing’s prior conclusion that it did not. Boeing shared this conclusion and the supporting SRB analysis with the FAA.
Boeing is issuing a display system software update, to implement the AOA Disagree alert as a standard, standalone feature before the MAX returns to service. When the MAX returns to service, all MAX production aircraft will have an activated and operable AOA Disagree alert and an optional angle of attack indicator. All customers with previously delivered MAX airplanes will have the ability to activate the AOA Disagree alert."
Emergency AD and Runaway Stabilizer procedure
For full details of the evolution of the runaway stabilizer procedure over the history of the 737, follow this link.
Following the Lion Air accident, on 7 Nov 2018 the FAA issued an Emergency AD (2018-23-51) and Boeing issue an Ops Manual Bulletin (TBC-19) for MAX Runaway Stabilizer procedure directing operators to “existing flight crew procedures" to address circumstances involving erroneous angle-of-attack sensor information.
On 18 Nov 2020 the FAA issued AD 2020-24-02 requiring several 737 MAX design and QRH changes as part of the ungrounding order. This included a change to the Runaway Stabiliser procedure as follows:
A key difference to the previous procedure is the recognition criteria have changed from a "continuous" uncommanded movement to "continuously or in a manner not appropriate for flight conditions".
On 11 Dec 2019 House Transportation Committee Chairman Peter DeFazio referred to this AD and procedure by saying that “The FAA issued an emergency airworthiness directive that purported to inform pilots on how to respond to an erroneous activation of MCAS while actually never mentioning the system by name, In fact, during the certification of the 737 MAX Boeing actively pushed the FAA to remove references to the MCAS from the flight crew operating manual, as revealed in the emails and instant messages from Boeing executive Mark Forkner.”
Ops Manual Bulletin TBC-19
This is a copy of the bulletin, it has a different reference (MLI-15) because it is with a different airline; TBC = The Boeing Company
Stab Trim Cut-Out Switches
MAIN ELEC and AUTO PILOT Stab trim switches now either switch will cut-off both main electric and autopilot stab trim. They are renamed PRI and B/U (primary and backup). The switches are guarded in the NORMAL position (switch up) and CUTOFF is switch down.
Comments Regarding Disabling of Column Cutout Switches
Comment summary: Two commenters suggested changing the design and function of the column cutout switches on the 737 MAX to be more similar to those on earlier Boeing Model 737 designs.
FAA response: The column cutout switch function of earlier Boeing Model 737 models would not allow for MCAS activation.
Column cutout switches on earlier Boeing Model 737 models allow the flightcrew the capability to interrupt (cut out) a stabilizer command in one direction by making a control column input in the other direction (e.g., an airplane nose-down stabilizer command will be interrupted by pulling the control column aft). The 737 MAX has the same column cutout feature, but it is temporarily disabled during the short duration of an MCAS activation.
MCAS operates only during high-AOA events, which are typically caused by the flightcrew pulling aft on the control column. To allow MCAS to operate as intended, the FCC temporarily disables the column cutout switches when MCAS is activated (makes a command). Without this temporary disable feature, the MCAS command to move the stabilizer in the airplane nose-down direction would otherwise be interrupted by the column cutout switches.
After the MCAS activation, the column cutout switches revert to a configuration where control column inputs will interrupt stabilizer commands in the opposite direction. When MCAS is not making a command, the column cutout switches operate like they do on earlier models of the Boeing Model 737. It is only during the short duration of an MCAS command that the column cutout switches on 737 MAX airplanes operate differently than those on other Boeing Model 737 airplanes.
The new MCAS includes cross-FCC monitoring, which detects and stops erroneous FCCgenerated stabilizer trim commands (including MCAS). This protects against an erroneous FCCgenerated stabilizer trim command throughout the entire flight, including when the column cutout switches are temporarily disabled.
Manual Trim Wheel Loads
The report into the Ethiopian accident, appears to show that after the crew had switched off the Stab trim cut-out switches they were unable to operate the trim wheel manually and subsequently switched them back on again to get electric trim which unfortunately also allowed MCAS to reactivate. The reason for why the trim wheel could not be operated manually is still unknown (hopefully only until the final report is issued) but it is probable that the control forces on the stab, and therefore the wheel, were too high due to the very high IAS at the time. It is now known that the FAA has doubts about the ability of some pilots (eg women) to have the level of strength required to operate the manual trim wheel at high IAS. This is applicable for all series of 737, not just the MAX.
On Friday 17 May, Boeing spokesman, Gordon Johndroe, said that Boeing has made corrections to 737 MAX simulator software and the company has provided additional information to device operators. He said the changes will ensure that the simulator experience is representative across different flight conditions and will improve the simulation of force loads on the manual trim wheel that helps control the airplane.
The comments came after the New York Times reported that Boeing recently discovered that the flight simulators airlines use to train pilots could not adequately replicate conditions that played a role in the 737 MAX crashes.
As a point of interest, the stab trim wheel on the MAX is 1 inch less in diameter than in all previous generations of 737. This would slightly reduce the force that the crew could turn the wheel as the handles are located near the circumference.
Update 20 Nov 2020
The issue of stab trim wheel loads was addressed in AD 2020-24-02 as follows:
Comments Regarding Manual Trim Forces
Comment summary: Many commenters, including the Allied Pilots Association, ALPA, BALPA, Ethiopian Airlines Group, and the UAE GCAA, expressed concerns regarding the 737 MAX manual trim system and the forces required to control and trim the aircraft following a failure of the STS (including MCAS). Some questioned the mechanical advantage provided by the manual trim system and whether it had been evaluated in flight testing. A commenter stated that it takes 15 turns of the pitch trim wheel to get just one degree of horizontal stabilizer movement, and some pilots may lack the strength to make those turns if the required force is too high. The commenter suggested pilots should be required to take a yearly strength test to determine whether they are capable of pulling a yoke or turning the pitch trim wheel in simulated emergency conditions.
FAA response: Following the Ethiopian Airlines accident, the 737 MAX manual trim system design and force requirements were an area of intense focus by the Ethiopian Aircraft Accident Investigation Bureau, the FAA, Boeing, and other CAAs, which continued throughout the FAA's evaluation and testing of the new FCC software and new MCAS during certification. The data from the Ethiopian Airlines accident indicates that the high trim wheel forces experienced during that accident were the result of significant horizontal stabilizer mis-trim combined with excessive airspeed. The new FCC software limits the maximum mis-trim that could occur for any foreseeable failure of the STS, thus ensuring the pilot can maintain control of pitch using the column only, without requiring exceptional pilot skill, strength, or alertness. Additionally, the FAA evaluated the manual trim system for the unlikely event that manual trim will be necessary. This included detailed analysis of manual trim wheel forces as a function of both dynamic pressure and out-of-trim state, testing to measure and assess the strength capability of an anthropometric cross-section of male and female subjects, and FAA flight testing to quantitatively validate manual trim wheel forces and qualitatively evaluate the ability to control the airplane for continued safe flight and landing. These flight test conditions and the associated analysis included maximum out-of-trim conditions well beyond those possible for any failure conditions in the new MCAS design and included the most critical aircraft configurations and airspeeds to the operational airspeed limit of the flight envelope (referred to as Vmo/Mmo). The FAA determined that manual trim wheel forces meet FAA safety standards and do not require exceptional pilot skill or strength nor any special or unique handling techniques as suggested by some of the commenters. Improvements to the Runaway Stabilizer non-normal procedure proposed in the NPRM and mandated by this final rule include steps to help ensure column forces remain manageable and reduce manual wheel trim forces in the unlikely case where manual trim may be needed. Additionally, this AFM procedure and pilot training emphasize the first priority in an emergency is to maintain control of the airplane, and also include specific information about the manual trim system including techniques for effectively using manual trim. Therefore, the FAA has made no changes in finalizing this AD related to the manual trim system or related AFM non-normal procedures.
Stick Shaker
In both MCAS accidents the stick shaker operated continuously throughout the flights until impact. This undoubtedly added to the confusion, distraction and stress levels. It is the view of EASA, Allied Pilots Association, ALPA, BALPA, Ethiopian Airlines Group, and the UAE GCAA that the means to suppress an erroneous stick shaker, as is available on most other warnings, should be available to crew.
For a full explanation of the 737 stall warning system follow this link
The FAA View of the Stick Shaker Issue
The issue of disabling the stick shaker in-flight was addressed in FAA AD 2020-24-02 as follows:
Comments Regarding Crew Procedure To Disable Stick Shaker
Comment summary: Several commenters, including the Allied Pilots Association, ALPA, BALPA, Ethiopian Airlines Group, and the UAE GCAA, expressed concerns regarding the attention getting nature of the stick shaker and requested a change to the procedures to include a means to suppress an erroneous stick shaker, including procedures to pull the associated stick shaker circuit breaker. In contrast, a commenter expressed a concern with the possible safety risks of including a procedure to pull the stick shaker circuit breaker in order to silence the warning.
FAA response: The FAA infers that the commenters are suggesting there is an unacceptably high flightcrew workload when stick shaker is activated erroneously. The 737 stall warning/stick shaker is, by design, attention getting and can be a distraction during an erroneously high-AOA event. However, after careful evaluation, the FAA has not changed the AFM non-normal procedure to include pulling the stick shaker circuit breakers in this final rule, for the following reasons.
The FAA evaluated all failure conditions of the new FCC software as part of certification of the proposed system changes. The new FCC software removes the potential for repeated, uncommanded MCAS inputs in the presence of an erroneous high AOA sensor input. This new design therefore removes the most significant contributor to unacceptably high flightcrew workload. With the new FCC software on the 737 MAX, the FAA tested and assessed all remaining flight deck effects, including erroneous stick shaker, during all foreseeable failure conditions, including high-AOA sensor failures during the most critical phases of flight (such as during takeoff or go-around). With the remaining flight deck effects and associated crew workload, these failures and effects were found compliant and safe.
The FAA considered the commenters' concerns that an erroneous stick shaker may pose a distraction for the crew, and evaluated that scenario with procedures that include steps to silence an erroneous stick shaker stall warning via a circuit breaker pull. The FAA finds that an erroneous stick shaker, while it may pose a distraction to the flightcrew, does not affect controllability of the airplane. The stick shaker circuit breaker locations also do not meet FAA requirements for convenient operation for emergency controls for the complete range of pilots from their normal seated position in the flight deck, leading to possible distraction from their primary duties to safely control and monitor the aircraft. Furthermore, inclusion of these additional steps would add cognitive and physical workload to an already substantial Airspeed Unreliable non-normal procedure, and errors in locating and pulling the correct circuit breaker may lead to other airplane hazards. Balancing the concerns associated with adding a procedure to pull circuit breakers against the distraction of an erroneous stick shaker, the FAA has concluded that the design is compliant and safe, and therefore no change to the proposed non-normal procedures related to silencing the 737 MAX stall warning is required for this AD.
The Southwest Airlines Pilots Association said in response to the FAA’s final AD that “Most MAX operators, with the exception of those in the United States, have developed a procedure for pulling a circuit breaker in just such an occurrence, thereby reducing distractions and flight deck confusion, No U.S. pilot should have to use captain’s emergency authority to accomplish this procedure when communication is near impossible due to noise and creating a significant distraction on the flight deck.”
The EASA and TC View of the Stick Shaker Issue
EASA issued a proposed AD 20-184 on 24 Nov 2020 cancelling the ‘suspension of flight operations‘. In it was the following requirement:
"install a button (coloured cap) on each stick shaker circuit breaker, on panels P6-1 and P18-2"
EASA are unlikely to drop this requirement and will require the addition of steps in associated QRH procedures adding the pulling of the c/b's as required.
The EASA Airspeed Unreliable QRH procedure has some steps and notes which refer to deactivating the stick shaker:
"A nuisance stick shaker may be deactivated at pilot's discretion. This improves recognition of a stall warning on the opposite side."
and
"If deactivating stick shaker is needed: Only the active stick shaker should be deactivated. Deactivate erroneous stick shaker."
TC issued a similar requirement:
"During dedicated simulator testing, Transport Canada test pilots found that, following the activation of the stick shaker, the constant noise and vibration was a significant impediment to the safe operation of the aeroplane for the remainder of the flight. Transport Canada therefore requires that the AFM be modified to add a means to disable a nuisance stick shaker. The disabling of the stick shaker also improves the crew’s recognition of the stall warning and disables an incorrect activation of the elevator feel shift. As the means to disable the nuisance stick shaker is through the use of circuit breakers (CBs), Transport Canada is mandating the incorporation of Boeing SB 737-27-1320. This SB requires the addition of coloured caps on CBs for the stick shaker, to allow for ease of identification. The step, to disable a nuisance stick shaker within the airspeed unreliable procedure, is included in the Transport Canada AFM Appendix that is an integral part of the FCC operational program software (OPS), software version P12.1.2, modification."
FAA Actions
11 March 2019
The FAA issued a Continued Airworthiness Notification to the International Community (CANIC), providing information regarding FAA continued operational safety activity related to the Boeing 737-8 and Boeing 737-9 (737 MAX) fleet. (available here)
Situation description: Following the accident of an Ethiopian Airlines Boeing Model 737-8 airplane on March 10, 2019, the National Transportation Safety Board (NTSB) as the accredited representative, and the FAA as Technical Advisors, are supporting the Ethiopian Accident Investigation Bureau. The FAA has dispatched personnel to support the investigative authorities in determining the circumstances of this event. All data will be closely examined during this investigation, and the FAA will take appropriate action if the data indicates the need to do so.
External reports are drawing similarities between this accident and the Lion Air Flight 610 accident on October 29, 2018. However, this investigation has just begun and to date we have not been provided data to draw any conclusions or take any actions.
Following the Lion Air Flight 610 accident, the FAA has completed these activities in support of continued operational safety of the fleet:
- Issued FAA emergency Airworthiness Directive (AD) 2018-23-51 on November 7, 2018
- Validated that airplane maintenance and functional check instructions on Angle of Attack (AOA) vane replacement were adequate
- Conducted simulator sessions to verify the Operational Procedures called out in FAA AD 2018-23-51
- Validated AOA vane bench check calibration procedures were adequate
- Reviewed Boeing’s production processes related to the AOA vane and Maneuvering Characteristics Augmentation System (MCAS)
Ongoing oversight activities by the FAA include:
- Boeing’s completion of the flight control system enhancements, which provide reduced reliance on procedures associated with required pilot memory items. The FAA anticipates mandating these design changes by AD no later than April 2019.
- Design changes include:
MCAS Activation Enhancements
MCAS AOA Signal Enhancements
MCAS Maximum Command Limit
- Boeing’s plans to update training requirements and flight crew manuals to go with the MCAS design change include:
o Airplane Flight Manual (AFM) and Flight Crew Operations Manual (FCOM)
o Quick Reference Handbook (QRH) - notes in Speed Trim Fail checklist
o Airplane Maintenance Manual (AMM)
o Interactive Fault Isolation Manual (iFIM)
o Boeing has proposed Level A training impacts
Aircraft/engine make, model, and series: The Boeing Company Model 737-8 and 737-9 airplanes (737 MAX)
The FAA said on 26 Nov 2019 that it has notified Boeing that the FAA will be the only issuer of aircraft-specific airworthiness certificates for all new 737 MAX planes, a role that it had shared with Boeing in the past.
In a letter sent to Boeing on Tuesday, the FAA said it "has determined that the public interest and safety in air commerce require that the FAA retain authority to issue airworthiness certificates and export certificates of airworthiness for all 737 MAX airplanes."
It said it will keep the authority to issue the certificates until it is confident Boeing has "fully functional quality control and verification processes in place" and that other Boeing procedures meet all regulatory standards.
23 May 2019
The FAA met with 30 international air regulators including China, the European Union, Brazil and Canada, in Texas to discuss progress on the MAX recertification including design changes, MCAS training and simulator requirements. When asked by reporters about a date for a return to service, the acting head of the FAA, Dan Elwell, said that he does not have a specific timetable to approve the 737 MAX for flight. “It’s a constant give and take until it is exactly right, It’s taking as long as it takes to be right,” he said, adding: “I’m not tied to a timetable.” “If you said October I wouldn’t even say that, only because we haven’t finished determining exactly what the training requirements will be, If it takes a year to find everything we need to give us the confidence to lift the [grounding] order so be it.”
August 2019
By late August 2019, the FAA said its staff has spent over 110,000 man hours dealing with MAX issues since the grounding.
23 Sep 2019
The Federal Aviation Administration and a team of technical experts met today with safety regulators from around the world to discuss the continuing efforts to return the Boeing 737 MAX jetliner to service. FAA Administrator Steve Dickson and Deputy Administrator Dan Elwell delivered opening remarks to more than 50 invited officials, all of whom will play a role in clearing the aircraft for further flight in their respective nations. Ali Bahrami, the FAA’s Associate Administrator for Aviation Safety, provided details on the FAA’s many activities to certify the aircraft since the group of regulators first met four months ago in Fort Worth, Texas. A senior Boeing Co. executive provided a technical briefing on the company’s efforts to address the safety regulators’ shared concerns.
During the meeting, Administrator Dickson pledged that the FAA would continue to share information about the FAA’s activities to ensure the proposed changes to the automated flight control system on the 737 MAX meet certification standards. “In the name of continuous improvement, we welcome feedback from our fellow civil aviation authorities, the aviation industry and the important independent reviews of the MAX and the FAA’s certification process,” Dickson said. Dickson told the group that the last few months have made it clear that, in the mind of the traveling public, aviation safety recognizes no borders. “Travelers demand the same high level of safety no matter where they fly,” he said. “It is up to us as aviation regulators to deliver on this shared responsibility.” The FAA continues to follow a thorough process, not a prescribed timeline, for returning the aircraft to passenger service. The FAA has a transparent and collaborative relationship with other civil aviation authorities as we continue our review of changes to software on the Boeing 737 MAX. Our first priority is safety, and we have set no timeframe for when the work will be completed. Each government will make its own decision to return the aircraft to service, based on a thorough safety assessment.
The FAA issued a 96-page Return to Service Preliminary Study in which it said that it “has preliminarily determined that Boeing’s proposed changes to the 737 MAX design, flightcrew procedures and maintenance procedures effectively mitigate the airplane-related safety issues” in the two fatal crashes.
The FAA said it is proposing an AD requiring four key Boeing 737 MAX design changes.
They are:
Update FCC software with new control laws to prevent erroneous MCAS activation.
Revise MDS software to generate an AOA DISAGREE alert to alert the pilots of a potential AOA sensor failure.
Revise certain flight-crew operating procedures to ensure that the flightcrew has the means to recognize and respond to erroneous stabilizer movement and the effects of a potential AOA sensor failure.
Increase the physical separation between the horizontal stabilizer trim arm wiring and the horizontal stabilizer trim control wiring, so that a wiring failure cannot create a hazard.
Re the proposed new QRH procedures:
The Airspeed Unreliable checklist would be revised to (1) add a step to allow the flightcrew to determine a reliable airspeed indication without the use of reference tables, (2) improve the procedure for go-arounds to allow for increased use of automation, (3) add a step to ensure that erroneous altitude information is not transmitted via the transponder to air traffic control (ATC), and (4) add erroneous AOA as a potential cause for unreliable airspeed conditions.
The Runaway Stabilizer checklist will have revisions to the criteria for this checklist’s use, to include when uncommanded horizontal stabilizer movement occurs continuously or in a manner not appropriate for current flight conditions. The revised checklist would include an explicit recall item that instructs the flightcrew to use their thumb-actuated trim switch to reduce forces on the control column. The checklist would also include a recall item to use the control column and thrust levers to control the airplane’s pitch attitude and airspeed. Finally, the checklist would be revised to add a reference item to manually trim the horizontal stabilizer for pitch control, and note that a two-pilot effort may be used to correct an out-of-trim condition.
The Stabilizer Trim Inoperative checklist of the AFM would be revised to better align with the other non-normal checklists, and modified to provide guidance for manually trimming the stabilizer for pitch control, noting that a two-pilot effort may be used and will not cause system damage.
A new Speed Trim Fail checklist, would be added to the AFM. This checklist would be used when the STS and MCAS functions are inoperative, and inform the flightcrew to continue normal operation. It would also note that the STS will not provide horizontal stabilizer trim inputs when the airplane deviates from its trimmed airspeed.
The FAA proposes adding the Stabilizer Out of Trim checklist to the AFM. The Stabilizer Out of Trim checklist would be used when the autopilot does not set the horizontal stabilizer trim correctly. Under the current design, the STAB OUT OF TRIM light illuminates in flight to inform the flightcrew that the airplane’s autopilot is not setting the horizontal stabilizer trim correctly. Under the new design, as part of the aforementioned FCC software update, this light will now also illuminate on the ground, to inform the flightcrew of a partial failure of a flight control computer. If the airplane is on the ground, the checklist will instruct the flightcrew to not take off. The checklist provides additional information for the flightcrew to use if the airplane is in flight.
The FAA proposes to add an AOA Disagree checklist as a procedure to the AFM, because the FAA proposes that the AOA DISAGREE alert be available on the PFDs for all 737 MAX airplanes. Therefore, this proposed checklist would be used when there is an indication, such as an AOA DISAGREE alert, that the airplane’s left and right AOA vanes disagree. The checklist would inform the flightcrew to accomplish the Airspeed Unreliable checklist.
The FAA proposes to add the ALT Disagree checklist as a procedure to the AFM. This checklist is used when the captain’s and first officer’s altitude indicators disagree, generating an ALT DISAGREE alert on the airplane’s PFDs. This proposed checklist would provide procedures to the flightcrew that would initially be driven by whether there is also an IAS DISAGREE alert shown on the airplane’s PFDs. The checklist would also provide additional steps for the flightcrew to subsequently complete for the descent, approach, and landing phases of flight.
The final checklist that the FAA proposes to add to the AFM is a new IAS Disagree checklist. This checklist is used when captain’s and first officer’s airspeed indicators – their “indicated airspeed” or “IAS” – disagree. The checklist directs the flightcrew to accomplish the Airspeed Unreliable checklist.
The FAA issued draft Flight Standardization Board Report FSBR B737 Rev 17 for comments by 2 Nov 2020.
"The purpose of this revision is to add training requirements for Maneuvering Characteristics Augmentation System (MCAS), Autopilot Flight Director System (AFDS) enhancements, and additional Special Emphasis Training. Appendices 2 and 3 reflect applicable table updates from the Boeing 737-800 to the Boeing 737-8 and from the Boeing 737-8 to the Boeing 737-800. Appendix 7 was added to delineate ground and flight training necessary to operate the 737 MAX modified with Flight Control Computer (FCC) software version 12.1.2."
18 Nov 2020
FAA Administrator Steve Dickson today signed an order (PDF) that paves the way for the Boeing 737 MAX to return to commercial service. Administrator Dickson’s action followed a comprehensive and methodical safety review process (PDF) that took 20 months to complete. During that time, FAA employees worked diligently to identify and address the safety issues that played a role in the tragic loss of 346 lives aboard Lion Air Flight 610 and Ethiopian Airlines Flight 302. Throughout our transparent process, we cooperated closely with our foreign counterparts on every aspect of the return to service. Additionally, Administrator Dickson personally took the recommended pilot training and piloted the Boeing 737 MAX, so he could experience the handling of the aircraft firsthand.
In addition to rescinding the order that grounded the aircraft, the FAA today published an Airworthiness Directive (PDF) specifying design changes that must be made before the aircraft returns to service, issued a Continued Airworthiness Notification to the International Community (CANIC) (PDF), and published the MAX training requirements. (PDF) These actions do not allow the MAX to return immediately to the skies. The FAA must approve 737 MAX pilot training program revisions for each U.S. airline operating the MAX and will retain its authority to issue airworthiness certificates and export certificates of airworthiness for all new 737 MAX aircraft manufactured since the FAA issued the grounding order. Furthermore, airlines that have parked their MAX aircraft must take required maintenance steps to prepare them to fly again.
The design and certification of this aircraft included an unprecedented level of collaborative and independent reviews by aviation authorities around the world. Those regulators have indicated that Boeing’s design changes, together with the changes to crew procedures and training enhancements, will give them the confidence to validate the aircraft as safe to fly in their respective countries and regions. Following the return to service, the FAA will continue to work closely with our foreign civil aviation partners to evaluate any potential additional enhancements for the aircraft. The agency also will conduct the same rigorous, continued operational safety oversight of the MAX that we provide for the entire U.S. commercial fleet.
19 Feb 2021
The FAA announced it is tracking all Boeing 737 MAX airplanes using satellite data under an agreement with air traffic surveillance firm Aireon LLC.
Aireon and L3Harris Technologies announced in November a new partnership with the FAA giving the agency broad access to Aireon’s real-time air traffic surveillance Automatic Dependent Surveillance-Broadcast (ADS-B) data.
The FAA said that “Aireon is providing the agency with ADS-B flight data for all Boeing 737 MAX aircraft.” “Aireon’s system will flag deviations from certain parameters during all phases of flight and alert the FAA’s aviation safety division. Safety engineers and inspectors will use the early notification to further analyze the incident,” the agency said.
The FAA 737 MAX monitoring began on Jan. 29, Aireon Chief Technology Officer Vinny Capezzuto said during a Feb. 12 web event hosted by Aviation Week. “You can literally monitor it on a situational awareness display and it has event detection tied into it,” Capezzuto said, adding the FAA can look for emergency codes and track other data. The system emails FAA “when events are detected and every day you get a report card on” data from flights from the previous day,” he said.
Joint Authorities Technical Review panel
29 April 2019
The JATR panel, convened by the FAA, had their first meeting. The FAA said about the JATR: “The JATR team will conduct a comprehensive review of the certification of the aircraft’s automated flight control system, The team will evaluate aspects of the 737 Max automated flight control system, including its design and pilots’ interaction with the system, to determine its compliance with all applicable regulations and to identify future enhancements that might be needed.”
The JATR is led by veteran NTSB investigator, Chris Hart and has is comprised of representatives from the civil aviation authorities of Australia, Brazil, Canada, China, the European Union, Japan, Indonesia, Singapore and United Arab Emirates.
11 Oct 2019
The JATR publish a 69-page series of findings and recommendations saying: "The JATR team found that the MCAS was not evaluated as a complete and integrated function in the certification documents that were submitted to the FAA.". "The lack of a unified top-down development and evaluation of the system function and its safety analyses, combined with the extensive and fragmented documentation, made it difficult to assess whether compliance was fully demonstrated."
The report also said that the FAA's long-standing practice of delegating "a high level" of certification tasks to manufacturers like Boeing needs significant reform to ensure adequate safety oversight.
"With adequate FAA engagement and oversight, the extent of delegation does not in itself compromise safety," the report said. "However, in the B737 MAX program, the FAA had inadequate awareness of the MCAS function which, coupled with limited involvement, resulted in an inability of the FAA to provide an independent assessment of the adequacy of the Boeing-proposed certification activities associated with MCAS."
The report also questioned FAA's limited staffing to oversee certification tasks it designated to Boeing and said there were an "inadequate number of FAA specialists" involved in the 737 MAX certification. It added there were signs that Boeing employees conducting FAA work faced "undue pressure. ..which may be attributed to conflicting priorities and an environment that does not support FAA requirements."
On 7 May 2019 the FAA said it had convened a multi-agency Technical Advisory Board (TAB) to review Boeing’s proposed software fix. The board consists of experts from the FAA, U.S. Air Force, NASA and the DOT's Volpe National Transportation Systems Center that were not involved in any aspect of the Boeing 737 Max certification. The board’s recommendations will “directly inform the FAA’s decision concerning the 737 Max fleet’s safe return to service.”. The new panel is separate from two other existing reviews created by FAA.
“The TAB is charged with evaluating Boeing and FAA efforts related to Boeing’s software update and its integration into the 737 MAX flight control system. The TAB will identify issues where further investigation is required prior to FAA approval of the design change,”
On 8 Nov 2019 a summary update to US lawmakers of proceeding in Congress revealed that the FAA told Congress: "The TAB presented its preliminary report to the FAA, detailing their finding that the MCAS design changes are compliant with the regulations and safe".
The TAB also made unspecified suggestions of actions that Boeing and FAA should complete before the MAX returns to flight, including final data submittals and document revisions, according to the summary. The TAB is also recommending “additional future activity” and FAA has agreed, according to the summary.
In its summary to Congress, the FAA said it is still in the process of determining how much training pilots on the plane will need before it returns to service. An FAA pilot group as well as a Joint Operations Evaluation Board made up of representatives from the FAA, Europe, Brazil and Canada will evaluate the need for training, according to the summary to lawmakers.
Joint Operational Evaluation Board (JOEB)
The Joint Operational Evaluation Board (JOEB), a multi-regulatory body established to look primarily at the order and priority of checklists and memory items.
It is composed of pilots from civil aviation authorities and airline flight crews from the United States, Canada, Brazil and the European Union and is tasked with evaluating 737 Max pilot training. “The flight crews will be subjected to rigorous validation testing that will help the FAA and other international regulators evaluate proposed flight training and emergency procedures,” says the FAA.
The JOEB conducted a 9 day series of simulator sessions in London Gatwick from 14 Sep 2020 to validate training requirements.
Following the simulator sessions, the JOEB sent its data to the FAA’s Flight Standardisation Board, which made final training recommendations to the FAA.
Joint European Max Operators Group (JEMOG)
JEMOG is a group which represents 10 European MAX customers, including Norwegian, Ryanair, Smartwings and TUI.
JEMOG responded to the FAAs draft AD (See FAA Actions 4 Aug 2020) made a proposal to further modify the Airspeed Unreliable QRH checklist as follows:
“Due to the revised QRH checklist sequence for Airspeed Unreliable, we recommend a caution statement should be added above the autopilot engagement instruction. The purpose of this statement will be to highlight to crew the risk of autopilot engagement while erroneous indications persist: After autopilot engagement verify that aircraft flight path including pitch, roll and airspeed are responding as intended.”
Flight Standardisation Board (FSB)
On 17 Apr 2019 the FAA issued a draft of the Flight Standardisation Board (FSB) report for the 737. The significant extracts are as follows:
3 HIGHLIGHTS OF CHANGE
The purpose of this revision is to add the B-737-7, B-737-8200, and Maneuvering Characteristics Augmentation System (MCAS). In Appendix 3, the Design Differences Table from the Boeing 737-800 to the Boeing 737-8 is revised to include ATA 27 Flight Controls addition of MCAS.
4 BACKGROUND
In March 2019, the FSB conducted an evaluation of the modified Maneuvering Characteristics Augmentation System (MCAS) for training and checking differences determination. The system enhancement is incorporated on all MAX series aircraft. The MCAS system was found to be operationally suitable.
9.2 Special Emphasis Areas.
B-737-MAX Maneuvering Characteristics Augmentation System (MCAS). The Speed Trim System (STS) provides speed and pitch augmentation. Speed stability augmentation is provided by the Speed Trim function of STS. Pitch stability augmentation is provided by the MCAS function of STS. MCAS ground training must address system description, functionality, associated failure conditions, and flight crew alerting. These items must be included in initial, upgrade, transition, differences, and recurrent training.
The level of training specified for MCAS is "B" which corresponds to "Oral or written exam or Tutorial computer-based instruction self-test (TCBI)"
The final FSB report is dependent on receipt of the JOEB review. This is not expected to be complete before the end of Oct 2020.
NTSB Actions
26 Sep 2019
The National Transportation Safety Board issued seven safety recommendations to the Federal Aviation Administration, calling upon the agency to address concerns about how multiple alerts and indications are considered when making assumptions as part of design safety assessments.
Aviation Safety Recommendation Report 19-01 was issued Thursday stemming from the NTSB’s ongoing support under International Civil Aviation Organization Annex 13 to Indonesia’s Komite Nasional Keselamatan Transportasi (KNKT) investigation of the Oct. 29, 2018, crash of Lion Air flight 610 in the Java Sea and the Aircraft Accident Investigation Bureau of Ethiopia’s investigation of the crash of Ethiopian Airlines flight 302 near Ejere, Ethiopia. All passengers and crew on board both aircraft – 346 people in all – died in the accidents. Both crashes involved a Boeing 737 MAX airplane.
The seven safety recommendations issued to the FAA are derived from the NTSB’s examination of the safety assessments conducted as part of the original design of Boeing’s Maneuvering Characteristics Augmentation System (MCAS) on the 737 MAX and are issued out of the NTSB’s concern that the process needs improvement given its ongoing use in certifying current and future aircraft and system designs.
“We saw in these two accidents that the crews did not react in the ways Boeing and the FAA assumed they would,” said NTSB Chairman Robert Sumwalt. “Those assumptions were used in the design of the airplane and we have found a gap between the assumptions used to certify the MAX and the real-world experiences of these crews, where pilots were faced with multiple alarms and alerts at the same time. It is important to note that our safety recommendation report addresses that issue and does not analyze the actions of the pilots involved in the Lion Air and Ethiopian Airlines accidents. That analysis is part of the ongoing accident investigations by the respective authorities.” The NTSB notes in the report that it is concerned that the accident pilots’ responses to unintended MCAS operation were not consistent with the underlying assumptions about pilot recognition and response that were used for flight control system functional hazard assessments as part of the Boeing 737 MAX design.
The NTSB’s report further notes that FAA guidance allows such assumptions to be made in certification analyses without providing clear direction about the consideration of multiple, flight-deck alerts and indications in evaluating pilot recognition and response. The NTSB’s report states that more robust tools and methods need to be used for validating assumptions about pilot response to airplane failures in safety assessments developed as part of the U.S. design certification process.
The seven recommendations issued to the FAA urge action in three areas to improve flight safety:
Ensure system safety assessments for the 737 MAX (and other transport-category airplanes) that used certain assumptions about pilot response to uncommanded flight control inputs, consider the effect of alerts and indications on pilot response and address any gaps in design, procedures, and/or training.
Develop and incorporate the use of robust tools and methods for validating assumptions about pilot response to airplane failures as part of design certification.
Incorporate system diagnostic tools to improve the prioritization of and more clearly present failure indications to pilots to improve the timeliness and effectiveness of their response.
20 Apr 2021 - DoT Initiated an Audit of FAA's Oversight of Boeing 737 MAX Return to Service
On March 13, 2019, the Federal Aviation Administration (FAA) issued a grounding order for the Boeing 737 MAX fleet after two accidents involving 737 MAX 8 aircraft raised significant safety concerns. At the request of the former Secretary of Transportation and members of Congress, our office has undertaken a series of reviews related to FAA’s certification of the 737 MAX 8 and its safety oversight. In this review—our third in the series— we will examine FAA’s actions following the two accidents, including FAA’s risk assessments, the grounding of the aircraft, and its subsequent recertification in November 2020. Accordingly, our objective is to evaluate FAA’s processes and procedures for grounding aircraft and implementing corrective actions, including for the Boeing 737 MAX.
The Federal Aviation Administration (FAA) has historically maintained an excellent safety record. However, two fatal accidents in 2018 and 2019 involving the Boeing 737 MAX 8 raised concerns about FAA’s oversight and certification of civilian aircraft manufactured and operated in the United States. At the request of Secretary of Transportation Elaine L. Chao and several members of Congress, our office has undertaken a series of reviews related to FAA’s certification of the MAX and its safety oversight, including the Agency’s oversight of Boeing’s Organization Designation Authorization (ODA). Our overall audit objective was to determine and evaluate FAA’s process for certifying the Boeing 737 MAX series of aircraft. In this report, we focused on assessing (1) the effectiveness of FAA’s guidance and processes for managing the certification of the 737 MAX 8 and (2) FAA’s oversight of the Boeing ODA.
What We Found
While FAA and Boeing followed the established certification process for the 737 MAX 8, we identified limitations in FAA’s guidance and processes that impacted certification and led to a significant misunderstanding of the Maneuvering Characteristics Augmentation System (MCAS), the flight control software identified as contributing to the two accidents. First, FAA’s certification guidance does not adequately address integrating new technologies into existing aircraft models. Second, FAA did not have a complete understanding of Boeing’s safety assessments performed on MCAS until after the first accident. Communication gaps further hindered the effectiveness of the certification process. In addition, management and oversight weaknesses limit FAA’s ability to assess and mitigate risks with the Boeing ODA. For example, FAA has not yet implemented a risk-based approach to ODA oversight, and engineers in FAA’s Boeing oversight office continue to face challenges in balancing certification and oversight responsibilities. Moreover, the Boeing ODA process and structure do not ensure ODA personnel are adequately independent. While the Agency has taken steps to develop a risk-based oversight model and address concerns of undue pressure at the Boeing ODA, it is not clear that FAA’s current oversight structure and processes can effectively identify future high-risk safety concerns at the ODA.
Our Recommendations
We made 14 recommendations to improve the Agency’s aircraft certification process and oversight of the Boeing ODA. FAA concurred with all 14 of our recommendations and provided appropriate actions and planned completion dates.
Responses
The FAA agrees with the recommendations and has plans to implement all of them, although it could take five years to complete them.
Boeing has responded to the report by saying "We have undertaken significant changes to reinforce our safety practices, and we have already made progress on several of the recommendations outlined in the final report."
US DoT Special Committee review of the FAA certification of the MAX
19 March 2019 - The U.S. Secretary of Transportation asked the Inspector General to ensure audit of Boeing 737-MAX 8 certification is part of review. (read letter here)
7 May 2019 - The US Department of Transportation appointed a committee to review the FAA’s process for certifying the Boeing 737 Max 8. The special committee is specifically tasked to review the 737 Max 8 certification process from 2012 to 2017. The findings from that review will provide the basis for recommendations for future improvements. The committee’s goal is to make proposals to improve “the FAA's aircraft certification process, including recommendations on delegations of authority and training, and improvements to other certification processes. Topics for investigation include the FAA’s certification process and timelines, and the process under which the FAA delegates some certification and oversight work to aircraft manufacturers and their employees.
The committee is led by co-chairs Lee Moak, the vocal former president of the Air Line Pilots Association (ALPA), and Darren McDew, former commander of the Air Force’s transportation command, a unit that oversees US military transportation. four other members hail from government, academia and industry. They include Amy Pritchett, head of The Pennsylvania State University’s aerospace engineering department and former director of NASA’s aviation safety programme, and Gretchen Haskins, chief executive of HeliOffshore, an association focused on safe offshore operation of helicopters. Other members include Amtrak’s chief safety officer Kenneth Hylander, who formerly was chair of the Flight Safety Foundation and has worked at Delta Air Lines and Northwest Airlines, and David Grizzle, a Republic Airways board member who formerly was the FAA’s chief counsel and head of its air traffic organisation.
16 Jan 2020 - The report on the FAA’s aircraft certification process, with particular focus on the Boeing 737 MAX 8 certification program was published.
Committee Conclusion
The Committee found the FAA’s overall certification system to be effective. It also concluded that reforms must be adopted to help our extremely safe aviation system become even better at identifying and mitigating risk. The Committee determined that potential vulnerabilities within our complex, global aviation system will be mitigated by better use of data and safety management systems, better integration of human factors, enhanced coordination and communication, and the harmonization of global standards. The Committee concluded that some of the decades-old industry assumptions used in the certification of aircraft are no longer valid when applied to today’s rapidly evolving, global aviation environment.
As reflected by the findings and recommendations listed below, the Committee seeks to make our safe aviation system even safer—to mitigate risk and bolster safety worldwide. In this ongoing pursuit of safety, the Committee cautions against any actions that would systematically dismantle the FAA’s current certification system and its use of delegated authority. Any radical changes to this system could undermine the collaboration and expertise that undergird the current certification system, jeopardizing the remarkable level of safety that has been attained in recent decades. The Committee emphasizes that the suggested safety benefits of these proposed reforms cannot be fully realized unless adopted and practiced globally. The Committee, therefore, encourages the United States to adopt these reforms and then take a leadership role in promoting these safety enhancements worldwide.
The report made 35 recommendations and is available here:
On 18 Mar 2019, the Department of Justice’s Fraud Section opened a criminal investigation into the development and certification of the Boeing 737 MAX by the FAA and Boeing. The Department of Transportation’s Inspector General and the FBI are participating in the investigation. Federal attorneys are gathering evidence through a federal grand jury seated in Washington, D.C. Grand jury proceedings are conducted in secret and the Justice Department has declined to comment on the investigation. The FAA and Boeing have also declined to comment.
The former 737 MAX chief technical pilot, Mark Forkner, now a first officer for Southwest Airlines, has invoked his Fifth Amendment rights and refused to turn over documents subpoenaed by the Justice Department as part of its broad investigation into the crashes in Indonesia and Ethiopia. He referred questions to his attorney when reached by phone. His attorney, David Gerger, of Houston, did not respond to inquiries.
Forkner played a key role in the development of the aircraft and worked for Boeing from 2011 to 2018. He’s now a first officer for Southwest. As chief technical pilot, Forkner’s job would have been to “provide flight operations, safety and technical support to Boeing internal and external customers at multiple levels” according to a job posting for a chief technical pilot on another airframe.
While “taking the Fifth” is often perceived as an admission of guilt, it’s use to avoid supplying documents is relatively rare and may just imply some legal wrangling between Forkner and the Justice Department according to experts consulted by the Seattle Times. The Times has previously reported that it was Forkner who suggested to the FAA that MCAS was not included in the FCOM. He, his lawyer and officials with the Justice Department all declined to comment on the legal move.
Update 7 Jan 2021
Boeing will pay $2.5 billion to settle the Justice Department investigation and admits that employees misled regulators about the safety of its 737 Max.
The government and the company said Thursday 7 Jan 2021 that the settlement includes money for the crash victims' families, airline customers and a fine.
Prosecutors said Boeing employees gave misleading statements and half-truths about safety issues with the plane to the Federal Aviation Administration, then covered up their actions.
“Boeing's employees chose the path of profit over candour,” said David Burns, acting assistant attorney general for the Justice Department's criminal division.
Boeing blamed two former pilots who helped determine how much training was needed for the Max. CEO David Calhoun said their conduct doesn't reflect Boeing employees as a whole or the character of the company.
“This is a substantial settlement of a very serious matter, and I firmly believe that entering into this resolution is the right thing for us to do - a step that appropriately acknowledges how we fell short of our values and expectations,” Calhoun said in a memo to employees.
The government will drop the criminal charge of conspiracy to defraud the U.S. after three years if Boeing follows the terms of the settlement.
The settlement removes uncertainty about criminal charges against Boeing, which is struggling to put the Max crisis behind it. Boeing still faces lawsuits by the families of passengers who died in the crashes, it has lost more than 1,000 orders for the Max, and its once-stellar reputation for engineering has suffered.
Boeing began working on the Max in 2011 as an answer to a new, more fuel-efficient model from European rival Airbus. Boeing admitted in court filings that two of its technical pilot experts deceived the FAA about a flight-control system called the Maneuvering Characteristics Augmentation System, or MCAS, that could point a plane's nose down if sensors indicated the plane might be in danger of an aerodynamic stall - that it might fall from the sky.
The system was not part of previous 737 models. MCAS was added because the Max's larger engines, which are mounted higher and farther forward on the 737's low-swept wings, gave the plane a tendency to tilt too far nose-up in some conditions.
Boeing downplayed the significance of MCAS and didn't mention it in airplane manuals. Most pilots didn't know about it.
Under the settlement announced 7 Jan 2021, which allows Boeing to avoid prosecution, Boeing will pay a $243.6 million fine, $1.77 billion in compensation to airlines that were unable to use their Max aircraft while they were grounded, and $500 million into a fund for the families of passengers who were killed in the crashes.
The $243.6 million fine, which the Justice Department said was at “low end” of the sentencing guidelines, represents the amount of money Boeing saved by not implementing full-flight simulator training for the 737 MAX, the agreement stated.
Boeing still faces dozens of lawsuits by families who lost relatives in the crashes. Three lawyers pressing cases in the Ethiopian crash said the settlement would not affect their pursuit of compensation.
House Transportation Committee Chairman Peter DeFazio, D-Ore, meanwhile, said the settlement amounted to “a slap on the wrist” for a company the size of Boeing.
“I hope the DOJ can explain its rationale for this weak settlement to the families, because from where I sit this attempt to change corporate behaviour is pathetic and will do little to deter criminal behaviour going forward,” DeFazio said in a statement.
U.S Senate Aviation and Space subcommittee Public Hearing
On 27 March 2019, the U.S Senate’s Aviation and Space subcommittee held a public hearing, where Daniel Elwell, the FAA’s acting administrator, defended the agency’s oversight of the jet. A second hearing, where Boeing officials might testify, is pending without a date
US Securities and Exchange Commission (SEC)
The mission of the U.S. Securities and Exchange Commission (SEC) is to protect investors, maintain fair, orderly, and efficient markets, and facilitate capital formation.
25 Sep 2022 - The SEC announced that the Boeing Company had agreed to pay $200 million to settle charges that it made materially misleading statements following the crashes, including statements assuring the public that the 737 MAX airplane was “as safe as any airplane that has ever flown the skies.”
According to SEC Chair Gary Gensler, “There are no words to describe the tragic loss of life brought about by these two airplane crashes….In times of crisis and tragedy, it is especially important that public companies and executives provide full, fair, and truthful disclosures to the markets. The Boeing Company and its former CEO, Dennis Muilenburg, failed in this most basic obligation. They misled investors by providing assurances about the safety of the 737 MAX, despite knowing about serious safety concerns. The SEC remains committed to rooting out misconduct when public companies and their executives fail to fulfill their fundamental obligations to the investing public.
The Office of Special Counsel
This is a federal agency that investigates whistleblower complaints. A whistleblower alleged that many FAA inspectors performing safety assessments on the 737 Max weren’t properly qualified to certify pilots or assess pilot training. The Office of Special Counsel sided with the whistleblower and said some internal FAA reviews had concluded the same thing. It found that 16 of 22 FAA pilots conducting safety reviews, including making decisions on the 737 Max when it came into service two years ago, “lacked proper training and accreditation,” according to the Office of Special Counsel letter to President Trump.
The FAA, which disputed the findings, issued a second statement with a stronger denial. “The FAA stands behind its response to Senator Wicker’s questions about the qualifications of Flight Standardization Board members,” it said in the latest statement. The agency’s communications to the lawmaker were cited in the Office of Special Counsel report.
On 23 Sep 2019, the U.S Office of Special Counsel (OSC) sent letters to the President and Congress alerting them that numerous Federal Aviation Administration (FAA) safety inspectors were not sufficiently trained to certify pilots. A whistleblower disclosed the allegations to OSC, which were substantiated by an agency investigation that calls into question the operational review of several aircraft, including the Boeing 737 MAX and the Gulfstream VII. OSC also found that responses by FAA to congressional inquiries regarding these allegations appear to have been misleading in their portrayal of FAA employee training.
“The FAA is entrusted with the critically important role of ensuring aircraft safety," said Special Counsel Henry J. Kerner. “The FAA's failure to ensure safety inspector competency for these aircraft puts the flying public at risk." Safety inspectors participate in Flight Standardization Boards, which are responsible for ensuring pilot competency by developing training and experience requirements. Pursuant to FAA policy, safety inspectors must have both formal classroom training and on-the-job training. FAA policy states that on-the-job training “does not substitute for required classroom training."
In its investigation, the FAA's independent Office of Audit and Evaluation (AAE) determined that 16 out of 22 safety inspectors, including those at the Seattle Aircraft Evaluation Group, had not completed formal training. Further, 11 of the 16 undertrained safety inspectors did not have Certified Flight Instructor certificates, which are a basic position requirement. Based on information provided by the whistleblower and material obtained via an ongoing investigation, this also included safety inspectors assigned to the 737 MAX. According to the whistleblower, the unqualified inspectors administered hundreds of certifications, known as “check rides," that qualified pilots to operate new or modified passenger aircraft.
Despite the training deficiencies uncovered by the investigation, the FAA provided a response to the Senate Committee on Commerce, Science, and Transportation on April 4, 2019 claiming that “all of the flight inspectors who participated in the Boeing 737 MAX Flight Standardization Board certification activities were fully qualified for these activities."
US Senate Commerce Committee - “Aviation Safety and the Future of Boeing’s 737 MAX”
U.S. Sen. Roger Wicker, R-Miss., chairman of the Senate Committee on Commerce, Science, and Transportation, will convene a hearing titled, “Aviation Safety and the Future of Boeing’s 737 MAX,” at 10:00 a.m. on Tuesday, October 29, 2019. This hearing is intended to examine issues associated with the design, development, certification, and operation of the Boeing 737 MAX following two international accidents in the last year. The committee will first hear from Boeing on actions taken to improve safety and the company’s interaction with relevant federal regulators. The second panel will follow and be comprised of government officials and aviation experts to discuss the status of Boeing 737 MAX and relevant safety recommendations.
Witness Panel 1: Mr. Dennis Muilenburg, President and Chief Executive Officer, The Boeing Company, accompanied by: Mr. John Hamilton, Vice President and Chief Engineer, Boeing Commercial Airplanes
Witness Panel 2: The Honorable Robert Sumwalt, Chairman, National Transportation Safety Board The Honorable Christopher Hart, Chairman, Joint Authorities Technical Review
Aircraft Certification Reform and Accountability Act of 2020
4 June 2020 - Sen. Roger Wicker (R-MS), the chair of the Senate Committee on Commerce, Science and Transportation, has introduced legislation to improve aviation safety in the United States. The legislation mandates adopting a Safety Management System for manufacturers, require the Federal Aviation Administration to review manufacturer assumptions regarding pilot reaction time, and ensure that flight testing includes a representative sample of pilots from around the world. According to Wicker, the bill would also reform the FAA’s certification process to prevent any lapses in safety protocol brought about by undue pressure or “regulatory coziness.”.“After reviewing the evidence from incident reports, soliciting recommendations from aviation experts, speaking to witnesses and stakeholders, and holding a series of hearings on aviation safety, I am introducing a bill that would take important steps to improve passenger aircraft regulations and safety,” Wicker said.
According to Wicker, the Aircraft Safety Improvement Act would impact manufacturers by mandating SMS for large aircraft and engine manufacturers to encourage a systematic approach to safety policy, assurance, risk management, and promotion. The bill would also require the development of best practices that all manufacturers would incorporate to make sure reports of undue pressure or regulatory coziness are addressed.
On the government side, the bill would require the FAA to review and reassess assumptions related to “human factors” when certifying aircraft; require the FAA to conduct more research into human factors with respect to the design and certification of aircraft, and require the FAA to review its capability to understand the safety implications of new or innovative technologies, materials, and procedures that designers and manufacturers of passenger aircraft may adopt or introduce. The bill would also require flight testing to be performed by international and domestic pilots.
Sen. Cantwell said following the bill’s introduction last June. that “A primary goal of this legislation is to make sure the FAA remains in the driver’s seat when it comes to certification. This bill makes it clear the FAA is in charge of the certification workforce and the approval process. Additionally, it requires the FAA to act on the NTSB’s recommendations on new safety standards for automation and pilot training.”
This bill addresses certain safety standards relating to the aircraft certification process.
Among other things, the bill requires the Federal Aviation Administration (FAA) to
direct U.S. aircraft and aerospace industry manufacturers to adopt safety management systems consistent with international standards and practices;
convene an expert panel to review organizations that design and produce transport airplanes and make recommendations for improvements;
require manufacturers to disclose to the FAA certain safety-critical information related to an aircraft;
conduct a comprehensive review of each manufacturing Organization Designation Authorization holder's capability to meet FAA regulations based on the holder's organizational structures, requirements applicable to officers and employees, and safety culture;
establish an appeal process to review decisions regarding a manufacturer's compliance with applicable design regulations;
revise and improve its process of issuing amended type certificates for modifying an aircraft;
initiate a call to action safety review of pilot certification standards in order to bring stakeholders together to share lessons learned, best practices, and implement actions to address any safety issues identified; and
conduct an evaluation of tools and methods that support the better integration of human factors and system safety assessments of aircraft flight deck and flight control systems into the FAA's certification process.
The Commerce Committee will hold a hearing on the FAA’s oversight of its certification process on June 17. FAA Administrator Steve Dickson will testify about issues associated with the Boeing 737 MAX following international accidents since 2018.
The Senate Committee on Commerce, Science, and Transportation - Aviation Safety Oversight Report
18 Dec 2020
U.S. Sen. Roger Wicker, R-Miss., chairman of the Senate Committee on Commerce, Science, and Transportation, today released the Committee’s investigation report on the Federal Aviation Administration (FAA). This investigation began in April of 2019, weeks after the second of two tragic crashes of Boeing 737 MAX aircraft, when Committee staff began receiving information from whistleblowers disclosing numerous concerns related to aviation safety.
“Twenty months ago, the Commerce Committee launched an investigation into FAA safety oversight. We have received disclosures from more than 50 whistleblowers, conducted numerous FAA staff interviews, and reviewed over 15,000 pages of relevant documents,” said Wicker. “Our findings are troubling. The report details a number of significant examples of lapses in aviation safety oversight and failed leadership in the FAA. It is clear that the agency requires consistent oversight to ensure their work to protect the flying public is executed fully and correctly.”
Some of the report’s more significant findings include:
FAA senior managers have not been held accountable for failure to develop and deliver adequate training in flight standards, despite repeated findings of deficiencies over several decades.
The FAA continues to retaliate against whistleblowers instead of welcoming their disclosures in the interest of safety.
The Department of Transportation Office of General Counsel (DOT OGC) failed to produce relevant documents requested by Chairman Wicker as required by Article I, Section I of the Constitution.
The FAA repeatedly permitted Southwest Airlines to continue operating dozens of aircraft in an unknown airworthiness condition for several years. These flights put millions of passengers at risk.
During 737 MAX recertification testing, Boeing inappropriately influenced FAA human factor simulator testing of pilot reaction times involving a Maneuvering Characteristics Augmentation System (MCAS) failure.
FAA senior leaders may have obstructed a DOT OIG review of the 737 MAX crashes.
The Commerce Committee released a fact sheet highlighting information on improper issuance of airworthiness certificates for 88 Southwest Airlines airplanes in November, 2019. Chairman Wicker also sent a letter to FAA Administrator Stephen Dickson expressing concern about these aircraft. In January of 2020, another fact sheet was released on alleged misconduct by FAA managers at the Flight Standards District Office in Honolulu, Hawaii. An update to this fact sheet was posted on June 17, 2020. The Committee is still reviewing the ongoing production of requested documents from the FAA and additional information received from whistleblowers.
Click here to read the Committee’s report, which includes a one-page executive summary and a six-page overview.
While the tragic 737 MAX crashes prompted several whistleblowers to come forward, and was the genesis of the investigation, the crashes or certification of the 737 MAX was not the focus. Yet, the investigation does suggest factors such as insufficient training and coziness could have contributed to the troubled certification. For example, whistleblowers alleged serious unethical behavior in pilot testing efforts to recertify the 737 MAX. Whistleblowers detailed concerns about human factor assumptions related to pilot reaction times to a runaway stabilizer event and/or faulty Maneuvering Characteristics Augmentation System (MCAS) activation. According to whistleblowers, these assumptions include a four second reaction time to identify a runaway stabilizer event which could be indicative of an MCAS activation. One whistleblower conducted his/her own ad hoc testing in a non-MCAS equipped simulator. The three flight crews presented with this scenario responded with reaction times to identify the problem in seven, nine, and eleven seconds. The time to complete the corrective action and correct the situation was forty-nine seconds, fifty-three seconds, and sixty-two seconds. In each instance, the simulator ended up in a nose pitch down altitude, but the simulated aircraft was able to recover.
The whistleblower emphasized these tests were completed in a 737-NG simulator, and MCAS was not an available feature or factor in the test scenarios. The whistleblower contends that the result of these tests indicate Boeing’s assumed reaction time of four seconds is unrealistic and found actual pilot reaction times were as much as four times the assumed time.
The Committee’s investigation discovered that at least one official FAA recertification test event was improperly influenced by Boeing. At least one FAA Aircraft Certification Test Pilot appears to have been complicit in this testing. Slow and incomplete responses to document requests and incomplete interviews have hindered progress on this specific topic. Some of the delays are due to conflict with ongoing criminal investigations. Therefore, it is impossible to determine how much of the systemic training, oversight, and management intervention problems detailed in this report may have contributed to the certification of the 737 MAX.
(Report Overview p6-7)
The House Committee on Transportation & Infrastructure
30 Sep 2020
the U.S. House Committee on Transportation and Infrastructure unanimously approved bipartisan legislation to reform the FAA’s aircraft certification process in the wake of
the 737 MAX crashes.
16 Sep 2020
The House Committee on Transportation & Infrastructure published its final report on the Design, Development, and Certification of the Boeing 737 MAX. It summarises:
This report was produced by Democratic staff of the Committee and is the culmination of the Committee’s investigative efforts assessing the costs, consequences, and lessons from the design, development, and certification of Boeing’s 737 MAX aircraft. The report reveals several unmistakable facts. The MAX crashes were not the result of a singular failure, technical mistake, or mismanaged event. They were the horrific culmination of a series of faulty technical assumptions by Boeing’s engineers, a lack of transparency on the part of Boeing’s management, and grossly insufficient oversight by the FAA—the pernicious result of regulatory capture on the part of the FAA with respect to its responsibilities to perform robust oversight of Boeing and to ensure the safety of the flying public. The facts laid out in this report document a disturbing pattern of technical miscalculations and troubling management misjudgments made by Boeing. It also illuminates numerous oversight lapses and accountability gaps by the FAA that played a significant role in the 737 MAX crashes.
The press release was as follows:
Today, Chair of the House Committee on Transportation and Infrastructure Peter DeFazio (D-OR) and Chair of the Subcommittee on Aviation Rick Larsen (D-WA) released the Committee’s final report on the Boeing 737 MAX. This report, prepared by Majority Staff, lays out the serious flaws and missteps in the design, development, and certification of the aircraft, which entered commercial service in 2017 before suffering two deadly crashes within five months of each other that killed a total of 346 people, including eight Americans.
The Committee’s 239-page report, which points to repeated and serious failures by both The Boeing Company (Boeing) and the Federal Aviation Administration (FAA), contains five central themes and includes more than six dozen investigative findings. These themes include:
Production pressures that jeopardized the safety of the flying public. There was tremendous financial pressure on Boeing and the 737 MAX program to compete with Airbus’ new A320neo aircraft. Among other things, this pressure resulted in extensive efforts to cut costs, maintain the 737 MAX program schedule, and avoid slowing the 737 MAX production line.
Faulty Design and Performance Assumptions. Boeing made fundamentally faulty assumptions about critical technologies on the 737 MAX, most notably with MCAS, the software designed to automatically push the airplane’s nose down in certain conditions. Boeing also expected that pilots, who were largely unaware that MCAS existed, would be able to mitigate any potential malfunction.
Culture of Concealment. Boeing withheld crucial information from the FAA, its customers, and 737 MAX pilots, including internal test data that revealed it took a Boeing test pilot more than 10 seconds to diagnose and respond to uncommanded MCAS activation in a flight simulator, a condition the pilot described as “catastrophic.” Federal guidelines assume pilots will respond to this condition within four seconds.
Conflicted Representation. The FAA’s current oversight structure with respect to Boeing creates inherent conflicts of interest that have jeopardized the safety of the flying public. The report documents multiple instances in which Boeing employees who have been authorized to perform work on behalf of the FAA failed to alert the FAA to potential safety and/or certification issues.
Boeing’s Influence Over the FAA’s Oversight Structure. Multiple career FAA officials have documented examples where FAA management overruled a determination of the FAA’s own technical experts at the behest of Boeing. These examples are consistent with results of a recent draft FAA employee “safety culture” survey that showed many FAA employees believed its senior leaders are more concerned with helping industry achieve its goals and are not held accountable for safety-related decisions.
“Our report lays out disturbing revelations about how Boeing—under pressure to compete with Airbus and deliver profits for Wall Street—escaped scrutiny from the FAA, withheld critical information from pilots, and ultimately put planes into service that killed 346 innocent people. What’s particularly infuriating is how Boeing and FAA both gambled with public safety in the critical time period between the two crashes,” Chair DeFazio said. “On behalf of the families of the victims of both crashes, as well as anyone who steps on a plane expecting to arrive at their destination safely, we are making this report public to put a spotlight not only on the broken safety culture at Boeing but also the gaps in the regulatory system at the FAA that allowed this fatally-flawed plane into service. Critically, our report gives Congress a roadmap on the steps we must take to reinforce aviation safety and regulatory transparency, increase Federal oversight, and improve corporate accountability to help ensure the story of the Boeing 737 MAX is never, ever repeated.”
“The Committee’s thorough investigation uncovered errors that are difficult to hear, but necessary to confront about the 737 MAX certification,” Chair Larsen said. “This report, combined with the findings and recommendations from the Lion Air and Ethiopian Airlines investigations, National Transportation Safety Board, Joint Authorities Technical Review and other entities, serve as a roadmap for changes to the FAA certification process. The 346 victims of the two tragic crashes and their families, as well as the traveling public rightfully expect Congress to act. As the Committee moves into the next phase of oversight, I will continue to work with Chair DeFazio and my colleagues to address the significant cultural and structural deficiencies identified in the report in order to improve safety.”
Additional information: At the direction of Chair DeFazio and Subcommittee Chair Larsen, the Committee launched an investigation into the design, development, and certification of the 737 MAX, and related issues, in March 2019, shortly after the second crash involving a Boeing 737 MAX aircraft. As part of the 18-month long investigation, the Committee held five public hearings with more than 20 witnesses; wrote nearly two dozen oversight letters, obtained an estimated 600,000 pages of documents from Boeing, the FAA, and others; received information and insight from former and current employees who contacted the Committee directly through the Committee’s whistleblower link; and interviewed dozens of current and former Boeing and FAA employees.
To access the Final Report, newly released accompanying records, including transcribed interviews of both senior Boeing and FAA officials about the 737 MAX, as well as past statements, hearing video, and more, click here.
13 Sep 2020
Keith Leverkuhn, who was vice president and general manager of the 737 MAX program at the time of its development, has said to the US House Transportation and Infrastructure Committee:
“I don’t consider the development of the airplane to be a failure,”
Re MCAS using a single AoA sensor he said: “I think based upon our understanding and our assumptions of flight crew actions, that it wasn’t a mistake,” “Clearly what was in error was our assumptions regarding the human machine interaction. Because the process relied on the industry standard of pilot reaction to a particular failure. And what was clear post accidents was that assumption was incorrect.”
Mike Teal, 737 MAX chief product engineer has said that if the 737 MAX design warranted simulator training, Boeing would have created it, while acknowledging that customers may have been disappointed.
“Would airlines have been pleased with that, of course they would not have,” he said, noting that Boeing had signalled all along that simulator training would not be necessary.
6 Mar 2020
The House Committee on Transportation & Infrastructure published its Preliminary Investigative Findings on the 737 MAX Costs, Consequences, and Lessons from its Design, Development, and Certification.
The conclusions are as follows:
Boeing’s design and development of the 737 MAX was marred by technical design failures, lack of transparency with both regulators and customers, and efforts to obfuscate information about the operation of the aircraft. During development of the 737 MAX, Boeing engineers raised safety concerns about MCAS being tied to a single AOA sensor. Another Boeing engineer raised concerns about not having a synthetic airspeed sensor on the 737 MAX.
In the wake of the Lion Air and Ethiopian Airlines tragedies, Boeing has now acknowledged some of these issues by planning to have two AOA sensors feed into MCAS, for instance. In January 2020, despite the fact that Boeing’s internal directive for the 737 MAX program made crystal clear that nothing should jeopardize Level B non-simulator pilot training requirements, Boeing reversed course by recommending that pilot simulator training on the 737 MAX will be needed before it returns to service. Boeing’s responses to safety issues raised in the 737 MAX program have consistently been too late.
The Committee’s investigation has also found that the FAA’s certification review of Boeing’s 737 MAX was grossly insufficient and that the FAA failed in its duty to identify key safety problems and to ensure that they were adequately addressed during the certification process. The combination of these problems doomed the Lion Air and Ethiopian Airlines flights.
In the weeks after the Lion Air crash, Boeing defended its development of MCAS to the FAA, writing that there was “no process violation or non-compliance” on multiple issues, including: removal of reference to MCAS from the FCOM; Boeing’s evaluation of “repeated unintended MCAS” activation; the fact Boeing did not evaluate “loss of one AOA followed by erroneous AOA” in the simulator; and the fact that the analysis Boeing did conduct was “completed prior to the design change to MCAS control law.”
The fact that multiple technical design missteps or certification blunders were deemed “compliant” by the FAA points to a critical need for legislative and regulatory reforms. Developing a transport category commercial aircraft that is compliant with FAA regulations but fundamentally flawed and unsafe highlights an aviation oversight system in desperate need of repair.
These preliminary investigative findings make clear that Boeing must create and maintain an effective and vigorous safety culture and the FAA must develop a more aggressive certification and oversight structure to ensure safe aircraft designs and to regain the confidence of the flying public. We hope these preliminary findings will help pave the way for legislative reforms as the Committee’s investigation continues to identify the actions and events that undermined the design, development, and certification of the 737 MAX aircraft and led to the tragic death of 346 people.
The US House of Representatives Transportation Committee chairman Rep. Peter DeFazio requested FAA administrator Stephen Dickson to investigate why the agency did not ground the 737 MAX, when its own analysis performed after the Lion Air crash, predicted as many as 15 more fatal accidents over the model’s service life if its flight control problem went uncorrected. Addressing the fifth transportation committee hearing on the MAX crashes, DeFazio noted that the FAA also reached the conclusion that 99 out of 100 flight crews could comply with the airworthiness directive and successfully react within ten seconds to the “cacophony” of alarms and alerts recounted in the Lion Air crash report.
Facing the Congress, Dickson had to answer on an internal forecast of the regulator dating from December 2018, two months after the Lion Air crash. The memo suggested that, without modification, the MCAS design flaw in the 737 MAX "could result in as many as 15 future fatal crashes over the life of the fleet ". This translates into one crash every three years during the 45 years of the estimated life of the program, potentially leading to the death of 2,900 people.
“Such an assumption we know now was tragically wrong,” he said. “Despite its own calculations, the FAA rolled the dice on the safety of the traveling public and let the MAX continue to fly until Boeing could overhaul its MCAS software. Tragically, the FAA’s analysis, which never saw the light of day beyond the closed doors of the FAA and Boeing, was correct.”
Peter DeFazio also said that “The FAA issued an emergency airworthiness directive that purported to inform pilots on how to respond to an erroneous activation of MCAS while actually never mentioning the system by name, In fact, during the certification of the 737 MAX Boeing actively pushed the FAA to remove references to the MCAS from the flight crew operating manual, as revealed in the emails and instant messages from Boeing executive Mark Forkner.”
Boeing have been working on a software modification to MCAS since the Lion Air accident. Unfortunately although originally due for release in January it was not released due to both engineering challenges and differences of opinion among some federal and company safety experts over how extensive the changes should be.
4 Nov 2019
The following update letter was written by the Committee Chairman to colleaugues:
"To summarize our key concerns, our investigation shows that from almost the start, Boeing had a bad design on MCAS with a single point of failure. Then, Boeing couldn’t even meet its own design requirements. MCAS was fundamentally flawed, and according to Boeing’s own analysis, could result in catastrophic consequences in certain cases. What’s more, Mr. Muilenburg’s answers to our questions were consistent with a culture of concealment and opaqueness and reflected the immense pressure exerted on Boeing employees during the development and production of the 737 MAX. Boeing leadership has said that if company officials knew during the design of the MAX what they know now about some of the technical flaws and other issues, they would have done things differently. Our investigation has already shown that Boeing leadership was aware of many of the problems that engineers are now attempting to fix during the design and development phase of the 737 MAX."
30 Oct 2019
The following slides (Courtesy of House Transportation Committee) were presented:
An email exchange was disclosed between Boeing employees from 2015 and read: "Are we vulnerable to single AOA sensor failures with the MCAS implementation?" The response today from CEO Dennis Muilenburg was that the email showed that "our engineers do raise questions, in an open culture," but that the single-sensor design met the standards.
John Hamilton, chief engineer for Boeing’s commercial airplane division, who testified alongside Muilenburg, said that single points of failure are allowed in airplane design depending on the hazard assessment. Any dissent the committee could present on the final assessment that a single sensor was merited “highlights that our engineers do raise questions and it’s an open culture.”
Transportation Committee Chair Peter DeFazio released a document showing that in June of 2018, after airlines had begun flying the new 737 Max planes, but months before the Lion Air crash, Boeing employees were raising concerns about how much time it would take for pilots to react to a potential MCAS failure. The document, called a "coordination sheet" and dated June 11, 2018, suggested some pilots would take more time than four seconds to react, and, "A slow reaction time scenario, (greater than) 10 seconds, found the failure to be catastrophic."
In the Ethiopian crash, the pilots are believed to have taken eight seconds to respond. John Hamilton acknowledged that engineers considered the impact of slow response times, but that simulator testing with a number of pilots supported its judgement that four seconds was a realistic expectation.
The NTSB Aviation Safety Recommendation Report 19-01 found Boeing was wrong in its assumptions and underestimated how long it would take pilots to react to such a failure, especially since the flight crew would be bombarded with multiple alerts and the stick shaker. Muilenburg told lawmakers he could not speak to that specific document but admitted "we made some mistakes on MCAS," and the company is now "revisiting these decades-long industry standards" on reaction time assumptions.
The above slide shows that the design requirements for MCAS stated that “MCAS shall not have any objectionable interactions with the piloting of the airplane,” and that “MCAS shall not interfere with dive recovery.” Rep. Greg Stanton challenged Muilenburg and Hamilton to admit that MCAS failed to meet those objectives. Hamilton asserted that pilots had the ability to counteract MCAS, but when challenged for a yes or no answer on whether it impacted dive recovery on the two fatal flights, Hamilton eventually answered “yes.”
The above slide is a proposed design from 2012 for an MCAS annunciator. Hamilton said that the design was not adopted because a failure of MCAS was incorporated into the failure indicator for the overarching speed trim system that MCAS is part of. Furthermore, an MCAS failure annunciator wouldn’t have helped pilots in the two crashes since the MCAS system didn’t fail; in each case MCAS was triggered by incorrect data from a faulty AoA sensor.
24 July 2019
The NTSB Chairman Robert Sumwalt said that "We will let the facts drive us, but I am told that our staff is working on a recommendation package that I would suspect we would have out in the next 60 days regarding design certification issues."
19 June 2019
Airline pilots, including Chesley “Sully” Sullenberger, told the committee that the US FAA should require more frequent flight simulator training for pilots and ensure adequate aircraft information is provided during training.
Sullenberger and Dan Carey, who represented the union of pilots at American Airlines, said during their testimonies that Boeing did not provide pilots with any information about this manoeuvring characteristics augmentation system (MCAS) prior to the Lion Air Crash in October. Acting FAA chief Dan Elwell has also said pilots were not given adequate information about the flight control software. "This is a global aviation crisis of trust and will require global solutions to restore and bolster aviation’s global safety culture and reputation," Carey said.
15 May 2019
The U.S. House Aviation Subcommittee of the Transportation and Infrastructure Committee held a 3 hour hearing on the status of the 737 MAX. Daniel Elwell, acting administrator of the FAA and NTSB chair Robert Sumwalt testified. The hearing was held to start producing answers on how the FAA certified the safety of the 737 MAX. So far, requested information from Boeing has not been forthcoming, noted Transportation and Infrastructure Committee Chairman Representative Peter DeFazio, a Democrat from Oregon who opened his statement by saying that Boeing has yet to turn over a single document as requested by the committee.
In this meeting, Elwell came under sharp questioning over how the FAA and Boeing had certified the plane as safe. The FAA has also been criticized for not requiring a clear description of the automated MCAS feature in documentation for pilots. House Transportation Committee Chairman Peter DeFazio, D-Ore., cited a Boeing engineer who was taped during a November meeting with a pilots' union saying MCAS might be seen just once in a million miles, and that "we try not to overload the crews with information that's unnecessary." "Do we really think that was unnecessary? It wasn't in the manual, and they didn't even know about it," DeFazio told Elwell.
Aviation Safety Whistleblower Report
On 13 Dec 2021, under the leadership of Chair Maria Cantwell, the Democratic staff of the Senate Committee on Commerce, Science, and Transportation released this report as part of the Committee’s continued investigation of the design and certification of the 737 MAX, and oversight of the Federal Aviation Administration’s implementation of Congressionally-mandated safety reforms under the Aircraft Certification, Safety, and Accountability Act.
For a good summary, read the following accompanying letter to the administrator of the FAA.
It made the follwoing recommendations:
Strengthen FAA direct oversight of the ODA program
Take measures to address undue pressure at Boeing ODA
Ensure sufficient FAA technical and engineering capacity for safety oversight
Limit delegation to industry until human factors assumptions are validated
Require that manufacturers adopt formal safety management systems with root cause analysis followed by corrective action
Measure and improve FAA safety culture for frontline staff
Mandate integrated aircraft safety analysis of designs
The last point is particularly relavent to the 737 MAX having been derrived from a much older design. With regard to this specific recommendation they said:
The “Changed Product Rule” allowed FAA to certify the 737 MAX according to dated airworthiness standards.
FAA should continue to update the “Changed Product Rule” in conjunction with international partners, as required by sections 115 and 117 of the Aircraft Certification, Safety, and Accountability Act, so that proposals for variants of existing aircraft designs (amended type certificates) have to undergo an integrated system safety analysis, taking in consideration the cumulative effects of proposed design changes to the aircraft, human factors issues, and impacts on training for pilots and maintenance personnel.
Emails discussing MAX differences from NG and differences to reduce certification and training impact
The The House Committee on Transportation & Infrastructure (above) asked Boeing to release documents and emails surrounding the design decisions on the MAX. These documents became public in Jan 2020 and contain astonishing revelations about the decision making process of certain MAX differenc
The introduction of Synthetic Airspeed and its effect on the Airspeed Unreliable NNC checklist
The new I-ADIRU
The effect of differences on Level B training requirements, ie full transition course and simulator training or just 2 hours CBT (cost implications)
Treating MCAS as a speed trim type function to "reduce certification and training impact". Furthermore the acronym MCAS would only be used internally, all external references would be to Speed Trim
Regarding the above regadcted emails, the Wall Street Journal reported on 17 Sep 2021 that:
Federal prosecutors are preparing to indict a former Boeing test pilot suspected of misleading aviation regulators over the safety issues blamed for two fatal 737 MAX crashes, the Wall Street Journal reported on Thursday.
Mark Forkner was the lead contact between the aviation giant and the United States' Federal Aviation Administration over how pilots should be trained to fly the planes, the Journal said.
According to documents published in early 2020, Forkner withheld details about the planes' faulty flight handling system known as the Maneuvering Characteristics Augmentation System, or MCAS -- later blamed for both crashes -- from regulators.
The 737 MAX was formally certified in March 2017, but was grounded worldwide for 20 months following two crashes in October 2018 and March 2019 that killed 346 people.
The MAX was allowed to fly again at the end of 2020, once the MCAS software was modified.
Boeing has acknowledged its responsibility in misleading regulators and agreed to pay more than $2.5 billion dollars to settle certain lawsuits.
Neither the US Justice Department nor Forkner's lawyer responded to requests for comment.
The Wall Street Journal said it was not clear what charges Forkner would face.
Internal emails show Forkner felt intense pressure to comply with a “program directive” to keep down costs and protect the jet’s development schedule by ensuring that regulators and airlines perceived the MAX as so minimally changed from the previous 737 model that pilots would find little difference. Forkner left Boeing to fly for Southwest Airlines in 2018, three months before the first MAX crash of Lion Air JT 610. He did not cooperate with the Department of Justice investigation into the jet’s certification and invoked the Fifth Amendment to avoid turning over documents when subpoenaed by federal prosecutors.
After the two deadly accidents in Indonesia and Ethiopia, the Department of Justice convened a grand jury to investigate allegations that Forkner had misled regulators by deliberately withholding information about MCAS.
Pressed by the Justice Department, Boeing turned over a series of emails and shocking instant message exchanges between Forkner and his deputy, Patrik Gustavsson, in which Forkner bragged about how he had “jedi mind tricked” airlines into choosing the minimum pilot training option – and so avoided the need for extensive training of pilots on full flight simulators that would make the MAX a more expensive and less competitive airplane. To pull that off, Forkner persuaded the FAA in March 2016 to omit any description of MCAS from the pilot manuals, arguing that it would activate only in extreme circumstances – as he said in an email, “WAY outside” normal flying conditions. That September, Boeing gave Forkner and his team a “Service Excellence Award” for achieving this critical MAX program goal. Forkner actively worked to the same end with regulators around the world, whom he disparaged in private messages as “fools” and “idiots.”
Tragically, Forkner even dissuaded Lion Air officials who wanted to train their pilots on MAX simulators that this was “a difficult and unnecessary training burden for your airline.” He mocked the Indonesian airline representatives for their “stupidity” in asking for such training and boasted that his efforts to dissuade them had saved Boeing “a sick amount of $$$$.” Yet after the Lion Air MAX was the first to crash in October 2018, killing 189 people, Boeing top executives blamed the pilots for not handling the plane properly.
In late 2017, with certification almost complete, Forkner discovered that Boeing – based on feedback from its flight test pilots – had changed the MCAS software to make it operate at a lower speed well within the normal flight range. “So basically I lied to the regulators (unknowingly),” he messaged Gustavsson. Gustavsson left Boeing in November 2019. There is no indication at this point that he will be charged. His lawyer declined to comment Friday.
The Deferred Prosecution Agreement states that Forkner and Gustavsson “intentionally withheld and concealed from the FAA … their knowledge of MCAS’s expanded operational scope” and indeed Forkner afterward reiterated to the FAA that all mention of MCAS should be removed from the pilot manuals. That agreement with Boeing, while clearly laying out a case for charges against Forkner, was criticized for the way it explicitly exonerates Boeing’s leadership. The case was brought by the then U.S. Attorney in the northern district of Texas, Erin Nealy Cox. Cox left the Department of Justice after the agreement and in June joined Kirkland & Ellis, Boeing’s lead corporate criminal defense law firm. On Kirkland’s website, she was welcomed to the firm as a partner by Mark Filip, who had signed the Deferred Prosecution Agreement on behalf of Boeing.
25 Feb 2020 - Three Democratic U.S. senators introduced sweeping legislation to reform how new airplanes are certified and overseen by U.S. regulators after the Boeing 737 MAX crashes. The bill would create an independent aircraft certification commission, bar Boeing Co and other manufacturers from tying employee compensation to delivery of airplanes and increase oversight of manufacturers that handle delegated certification tasks on behalf of the FAA. The legislation would also set new requirements for individuals handling delegated certification tasks and require regular audits.
The Fix
As of November 2020 the necessary changes required to cancel the ‘suspension of flight operations‘ as mandated by the FAA (AD 2020-24-02) and EASA (AD 20-184) are as follows:
Note that as MCAS is an FCC function, the modifications to MCAS are made to the FCC software. The new revision is known as FCC P12.1.2
There are three significant changes to MCAS / FCC software:
To give the system input from both angle-of-attack sensors, Currently MCAS only uses data from the angle of attack sensor on the side of the active FCC, (see AoA source). The system will have split vane monitor and Mid Value Select (MVS) input. This will both enhance detection of erroneous AoA vane behaviour and the MVS signal selection will pick the average of ADIRU L & R and the previous MVS output. If the output of the two AoA vanes differ by more than 5.5 degrees MCAS will be disabled.
To limit how much MCAS can move the horizontal stab to guarantee sufficient handling capability using elevator alone. In its original report, Boeing said that MCAS could move the horizontal stabilizer a maximum of 0.6 degrees. However, after the Lion Air crash, it told airlines that MCAS could actually move it 2.5 degrees, or half the physical maximum. Boeing reportedly increased the limit because flight tests showed that a more powerful movement was needed at high AoA rather than at high Mach.
A modification to the activation and resynchronisation schedule. MCAS will be limited to operate only for one cycle per high AoA event, rather than multiple. At present it will operate for 10s, pause for 5s and repeat for as often as it senses the high AoA condition is present. Furthermore the logic for MCAS to command a nose up stab trim to return to trim following pilot electric trim intervention or exceeding the forward column cutout switch, will also now be improved.
Furthermore there must be:
Revise the AFM and QRH to include revised operating procedures for:
Airspeed Unreliable
Runaway Stabilizer
Stabilizer Trim Inoperative
Speed Trim Fail
Stabilizer out of Trim
AOA Disagree
ALT Disagree
IAS Disagree
Revise the AFM to include revised limitations for Autopilot Single Channel Operation / Malfunction
Dispatch is not permitted with both autopilot systems inoperative
The autopilot disengage aural warning system must be operative for dispatch
The STAB OUT OF TRIM light must be operative for dispatch.
The speed trim function must be operative for dispatch
The SPEED TRIM FAIL light must be operative for dispatch
Dispatch is not permitted with both A/P ENGAGE Command (CMD) Switches (A and B) inoperative
Dispatch is not permitted with both A/P ENGAGE Command (CMD) switch lights inoperative
Dispatch is not permitted with both autopilot (A/P) disengage lights inoperative. Dispatch may be made with one A/P disengage light inoperative, provided the autopilot disengage aural warning is verified to operate normally before each flight.
Dispatch is not permitted with both Control Wheel Autopilot Disengage Switches inoperative. Dispatch may be made with one control wheel autopilot disengage switch inoperative provided the following conditions are met.
a) Mode Control Panel autopilot DISENGAGE bar is verified to operate normally before each departure.
b) Autopilot is not used below 1,500 feet AGL, and
c) Approach minimums do not require use of autopilot.
Both control wheel trim switch systems must be operative for dispatch
Changes to the on board displays MDS DPC OPS. This includes making the AoA Disagree Alert standard on all aircraft and offering a free option to have the AoA display on the PFD;
Explanation of MCAS to be added to FCOM
Pilot type conversion training to cover speed trim and MCAS, existing crew procedures and related software changes. Pilots with 737 NG or 737 MAX qualifications
will require:
5 hr. of transition training
3 hr. of simulator briefings and live scenarios
2 hr. of computer-based course work.
Enhancements to the maintenance documentation, including specifically to the Airplane Maintenance Manual (AMM) and Interactive Fault Isolation Manual (iFIM)
A computerized synthetic third AoA sensor system (discribed here)
Install a button (coloured cap) on each stick shaker circuit breaker, on panels P6-1 and P18-2 - Note this is an EASA only (and possibly Transport Canada) requirement. The FAA has rejected this option in AD 2020-24-02, arguing that the upgraded flight controls make it unnecessary and that having the pilot reach back and to pull the circuit breaker panel created both an additional risk of distraction and would add cognitive and physical workload. (Issue discussed here)
Horizontal Stabilizer Trim Wire Bundle Routing Change
Update 16 Apr 2019
the MCAS flight test program concluded after 120 flights / 203 hours flight test time. The Boeing CEO, Dennis Muilenburg flew on a 737 Max demonstration flight, where he “saw first-hand this software in its final form, operating as designed across a range of flight conditions”.
Update 29 May 2019
the Boeing CEO, Dennis Muilenburg said in an interview with CBS Evening News "The implementation of that software — we did not do it correctly. Our engineers discovered that. We are fixing it now. And our communication on that was not what it should have been. We clearly fell short. And the implementation of this [alert] was a mistake," he added. "We did not implement it properly."
Update 5 Aug 2019
the Boeing CEO, Dennis Muilenburg said that the MAX has conducted almost 500 test flights with the new FCC software. Muilenburg said that he has personally flown on two of the test flights, and that Boeing employees are “eager to do the same.”
Update 16 Sep 2020
Boeing said “The revised design of the MAX has received intensive internal and regulatory review, including more than 375,000 engineering and test hours and 1,300 test flights,”
Patrick Ky, executive director of the European Union Aviation Safety Agency (EASA) has said Boeing has agreed to install a "computerized third-sensor system" on the 737 MAX 10, followed by retrofits on the rest of the MAX fleet later.
Chronology of the Return to Service of the MAX
13 Jan 2023
Chinese passenger flights on the MAX resumed on 13 Jan 2023 with two domestic flights operated by China Southern Airlines from Guangzhou. China Southern currently has a fleet of 24 737 Max 8s.
10 Oct 2022
The first commercial 737 MAX flight has landed in China after a 4-year ban by the CAAC. The flight was operated by MIAT Mongolian Airlines and landed in Guangzhou from Ulaanbaatar on the morning of 10 Oct 2022. The MAX is now only still grounded in Russia.
01 Feb 2022
Ethiopian Airlines makes it first commercial MAX flight since its accident. The demonstration flight had journalists, diplomats and officials on board and was initially scheduled to reach neighbouring Kenya but remained within Ethiopia due to poor weather, officials on board said. While airborne, acting Chief Executive Officer Esayas Woldemariam told reporters that commercial flights would resume after the demonstration. "We made sure everything is in order, now we are doing...a demo flight so to speak. It is after this that we are availing it to commercial aviation," said Esayas.
21 Jan 2022
Hong Kongs Civil Aviation Department (CAD) permits MAX operations in its airspace.
31 Dec 2021
Vietnams CAAV approves MAX operations in its airspace. The decision was made on the ground of Boeing's safety measures based on the results of the investigation into the two crashes, assessment of aviation authorities around the world, and the safety index of the Boeing 737 Max after being licensed to operate again as well as the evaluation of the Aviation Safety Risk Assessment Council of the CAAV.
28 Dec 2021
Indonesia approves MAX operations in its airspace. Lion Air owns 10 737-MAX and Garuda one.
02 Dec 2021
The Chinese authority (CAAC) issued an AD of requirements to unground the MAX for operations in China. Titled "Corrective actions of Maneuvering Characteristics Augmentation System (MCAS) unsafe condition"
It is very similar to other authorities requirements and includes a coloured cap for the stick shaker circuit breaker.
22 Nov 2021
South Korea lifted its grounding order on the 737 MAX. Eastar Jet has 6 MAX. Korean Air Lines and other budget carriers like Jeju Air Co. and T'way Air Co., are expected to consider bringing the model to its fleet, after having delayed the plan over the safety issues
28 Oct 2021
CEO, Dave Calhoun said on 28 Oct 2021: “During the third quarter, we delivered 62 737s, the most since the first quarter of 2019. Since the FAA’s approval to return the 737 MAX to operations, we have delivered more than 195 737 MAX aircraft; and airlines have returned more than 200 previously grounded airplanes to service, safely flying more than 500,000 flight hours.”
He went on to say: “Demand also remains strong, and we have achieved eight straight months of positive net orders, largely driven by the 737. To meet this demand, we’re now producing at a rate of 19 airplanes per month, and plan to steadily increase that rate to 31 per month in early 2022.”
11 Oct 2021
James “J.D.” Detwiler of BBJ, which is celebrating its 25th anniversary this week at NBAA-BACE, said that "Since its return to service, as of mid-September 2021, the Max platform had flown more than 150,000 revenue flights, accumulating some 369,000 total flight hours and achieving service reliability exceeding 99.4 percent." and that “Regulators have confirmed that the airspace is opened to the 737 Max in 178 jurisdictions worldwide,”
06 Sep 2021
Singapore lifted its grounding order on the 737 MAX. Singapore Airlines has 6 MAX with another 8 to be delivered by 31 March 2022.
02 Sep 2021
Malaysia has on 2 Sep 2021 lifted its grounding order on the 737 MAX. The directive is applicable to local and foreign airlines operating commercial flights in Malaysia using the aircraft, the Civil Aviation Authority of Malaysia (CAAM) said in a statement on Thursday.
16 Aug 2021
India has on 26 Aug 2021 lifted its grounding order on the 737 MAX. This not only allows airlines to operate the MAX into and out of India but also to overfly India. They cited the perfect track record of the MCAS issues with other operators since its ungrounding elsewhere in the world.
11 Aug 2021
The MAX -7 in China has positioned from Pudong International (ZSPD) to Zhoushan Putuoshan (ZSZS) where it is expected to begin flight testing for ungrounding by the Chinese
authorities. After flight testing, the Chinese regulator is expected to issue an aircraft evaluation report and put it out for comment before pilot training can begin. China's aviation regulator has previously issued three requirements for the 737 MAX's return to service: certified design changes, sufficient pilot training, and definitive findings from the crash investigations.
20 Apr 2021
The Indian DGCA announced that Boeing 737 Max planes will be allowed to overfly Indian airspace but no commercial arrivals or departures will be allowed.
Foreign registered aircraft performing operational readiness flights followed by ferry flights to outside India may be exempt subject to conditions.
28 Feb 2021
The Saudi civil aviation authority (GACA) announced on Sunday that Boeing 737 Max planes will be allowed to return to service to and from the kingdom after meeting safety requirements.
27 Feb 2021
Australia authorises the 737 MAX to fly again in Australian airspace.
New Zealand’s Civil Aviation Authority (CAA) said it had worked closely with counterparts in Australia and Singapore on the return of the 737 MAX in New Zealand. “The CAA will not issue a blanket approval for the Boeing 737 MAX to fly into New Zealand but will work with any future operators on a case-by-case basis to clear flight operations into New Zealand,” the CAA said, noting Fiji Airways was still restricting international flights due to COVID-19.
17 Feb 2021
The UAE authorises the 737 MAX to fly again in UAE airspace.
12 Feb 2021
Nigeria authorises the 737 MAX to fly again in Nigerian airspace. A statement signed by the Director General, NCAA, Captain Musa Nuhu said the lifting of the ban came into effect on 12th February, 2021.
Transport Canada announce MAX ungrounding AD to be issued in Jan 2021. Details here
25 Nov 2020
The Brazilian regulator, ANAC has today ungrounded the MAX. ANAC superintendent of airworthiness José Roberto Honorato said the Brazilian regulator would simply apply the FAA conditions. The only Brazilian operator of the MAX is GOL who said last week it could resume flying Boeing 737 MAX jets by year-end.
24 Nov 2020
EASA issued a proposed AD 20-184. This PAD proposes to supersede EASA AD 2019-0051R1, cancelling the ‘suspension of flight operations‘ requirements of that AD. The affected Boeing 737-8 and 737-9 aeroplanes can be returned to service, provided that the required actions proposed in this PAD have been accomplished.
When asked about when EASA would unground the MAX, Patrick Ky, the head of the EASA said “We wanted to carry out a totally independent analysis of the safety of this aircraft, so we performed our own checks and flight tests,”. “All these studies tell us that the 737 MAX can return to service. We have started to put in place all the measures,” he said. “It is likely that in our case we will adopt the decisions, allowing it to return to service, some time in January.”
Officials confirmed a draft EASA directive proposing to end the grounding in Europe will be published next week, followed by a 30-day comment period. After finishing touches, that would lead to an ungrounding decision in January.
How long it takes for flights to resume in Europe depends on pilot training and the amount of time it takes airlines to upgrade software and carry out other actions mandated by EASA.
18 Nov 2020
FAA Administrator Steve Dickson today signed an order (PDF) that paves the way for the Boeing 737 MAX to return to commercial service. Administrator Dickson’s action followed a comprehensive and methodical safety review process (PDF) that took 20 months to complete. During that time, FAA employees worked diligently to identify and address the safety issues that played a role in the tragic loss of 346 lives aboard Lion Air Flight 610 and Ethiopian Airlines Flight 302. Throughout our transparent process, we cooperated closely with our foreign counterparts on every aspect of the return to service. Additionally, Administrator Dickson personally took the recommended pilot training and piloted the Boeing 737 MAX, so he could experience the handling of the aircraft firsthand.
In addition to rescinding the order that grounded the aircraft, the FAA today published an Airworthiness Directive (PDF) specifying design changes that must be made before the aircraft returns to service, issued a Continued Airworthiness Notification to the International Community (CANIC) (PDF), and published the MAX training requirements. (PDF) These actions do not allow the MAX to return immediately to the skies. The FAA must approve 737 MAX pilot training program revisions for each U.S. airline operating the MAX and will retain its authority to issue airworthiness certificates and export certificates of airworthiness for all new 737 MAX aircraft manufactured since the FAA issued the grounding order. Furthermore, airlines that have parked their MAX aircraft must take required maintenance steps to prepare them to fly again.
The design and certification of this aircraft included an unprecedented level of collaborative and independent reviews by aviation authorities around the world. Those regulators have indicated that Boeing’s design changes, together with the changes to crew procedures and training enhancements, will give them the confidence to validate the aircraft as safe to fly in their respective countries and regions. Following the return to service, the FAA will continue to work closely with our foreign civil aviation partners to evaluate any potential additional enhancements for the aircraft. The agency also will conduct the same rigorous, continued operational safety oversight of the MAX that we provide for the entire U.S. commercial fleet.
Commercial flights are scheduled to start on Dec. 29, just under six weeks after the FAA order was published on Nov 18.
Update 30 Sep 2020
FAA Chief Steve Dickson and Deputy Administrator Dan Elwell personally conducted a 2 hour evaluation flight at the controls of a Boeing 737 MAX on 30 Sep 2020. Dickson has repeatedly said he would not sign off the MAX until he flew it himself and was “satisfied that I would put my own family on it without a second thought.”. The flight by Dickson will fulfill “his promise to fly the aircraft before the FAA approves its return to service.”
After the flight Dickson said “I like what I saw on the flight. We are not to the point yet where we have completed the process,”
Update 10 Sep 2020
European Union Aviation Safety Agency (EASA) conducted a single flight test in Vancouver, Canada using aircraft 737-7 1E001. The flight lasted 2hr 27min. EASA said “While Boeing still has some final actions to close off, EASA judges the overall maturity of the re-design process is now sufficient to proceed to flight tests,”. Simulator tests were conducted in advance of the flights at a facility at London Gatwick from 1st September 2020.
Update 26 Aug 2020
Transport Canada has successfully completed a series of flight test activities of the updated MAX as part of the validation process. From August 23 to 25, 2020, Transport Canada’s flight test crew were flown to Seattle, Washington, to conduct evaluations on the engineering simulator at the Boeing facility and then at the end of the each test day, were flown back to Vancouver.
Update 4 Aug 2020
The FAA said it is proposing an AD requiring four key Boeing 737 MAX design changes.
Update FCC software with new control laws to prevent erroneous MCAS activation.
Revise MDS software to generate an AOA DISAGREE alert to alert the pilots of a potential AOA sensor failure.
Revise certain flight-crew operating procedures to ensure that the flightcrew has the means to recognize and respond to erroneous stabilizer movement and the effects of a potential AOA sensor failure.
Increase the physical separation between the horizontal stabilizer trim arm wiring and the horizontal stabilizer trim control wiring, so that a wiring failure cannot create a hazard.
Re the proposed new QRH procedures:
The Airspeed Unreliable checklist would be revised to (1) add a step to allow the flightcrew to determine a reliable airspeed indication without the use of reference tables, (2) improve the procedure for go-arounds to allow for increased use of automation, (3) add a step to ensure that erroneous altitude information is not transmitted via the transponder to air traffic control (ATC), and (4) add erroneous AOA as a potential cause for unreliable airspeed conditions.
The Runaway Stabilizer checklist will have revisions to the criteria for this checklist’s use, to include when uncommanded horizontal stabilizer movement occurs continuously or in a manner not appropriate for current flight conditions. The revised checklist would include an explicit recall item that instructs the flightcrew to use their thumb-actuated trim switch to reduce forces on the control column. The checklist would also include a recall item to use the control column and thrust levers to control the airplane’s pitch attitude and airspeed. Finally, the checklist would be revised to add a reference item to manually trim the horizontal stabilizer for pitch control, and note that a two-pilot effort may be used to correct an out-of-trim condition.
The Stabilizer Trim Inoperative checklist of the AFM would be revised to better align with the other non-normal checklists, and modified to provide guidance for manually trimming the stabilizer for pitch control, noting that a two-pilot effort may be used and will not cause system damage.
A new Speed Trim Fail checklist, would be added to the AFM. This checklist would be used when the STS and MCAS functions are inoperative, and inform the flightcrew to continue normal operation. It would also note that the STS will not provide horizontal stabilizer trim inputs when the airplane deviates from its trimmed airspeed.
The FAA proposes adding the Stabilizer Out of Trim checklist to the AFM. The Stabilizer Out of Trim checklist would be used when the autopilot does not set the horizontal stabilizer trim correctly. Under the current design, the STAB OUT OF TRIM light illuminates in flight to inform the flightcrew that the airplane’s autopilot is not setting the horizontal stabilizer trim correctly. Under the new design, as part of the aforementioned FCC software update, this light will now also illuminate on the ground, to inform the flightcrew of a partial failure of a flight control computer. If the airplane is on the ground, the checklist will instruct the flightcrew to not take off. The checklist provides additional information for the flightcrew to use if the airplane is in flight.
The FAA proposes to add an AOA Disagree checklist as a procedure to the AFM, because the FAA proposes that the AOA DISAGREE alert be available on the PFDs for all 737 MAX airplanes. Therefore, this proposed checklist would be used when there is an indication, such as an AOA DISAGREE alert, that the airplane’s left and right AOA vanes disagree. The checklist would inform the flightcrew to accomplish the Airspeed Unreliable checklist.
The FAA proposes to add the ALT Disagree checklist as a procedure to the AFM. This checklist is used when the captain’s and first officer’s altitude indicators disagree, generating an ALT DISAGREE alert on the airplane’s PFDs. This proposed checklist would provide procedures to the flightcrew that would initially be driven by whether there is also an IAS DISAGREE alert shown on the airplane’s PFDs. The checklist would also provide additional steps for the flightcrew to subsequently complete for the descent, approach, and landing phases of flight.
The final checklist that the FAA proposes to add to the AFM is a new IAS Disagree checklist. This checklist is used when captain’s and first officer’s airspeed indicators – their “indicated airspeed” or “IAS” – disagree. The checklist directs the flightcrew to accomplish the Airspeed Unreliable checklist.
The FAA issued a 96-page Return to Service Preliminary Study in which it said that it “has preliminarily determined that Boeing’s proposed changes to the 737 MAX design, flightcrew procedures and maintenance procedures effectively mitigate the airplane-related safety issues” in the two fatal crashes.
The UK CAA have today amended Safety Directive SD 2019/001 for the 737 MAX, to introduce the possibility for managed ferry flights into, out of, or through UK airspace for the purposes of essential maintenance or modification.
Boeing issue FOTB "737 MAX Return to Service Operational Readiness Flight" to provide inflight guidance on exercising airplane systems previously subjected to AMM preservation and depreservation tasks, and to confirm their inflight operation prior to 737 MAX Return to Service (RTS). During the depreservation of the airplane, airplane systems are tested extensively as part of the maintenance procedures. An Operational Readiness Flight profile can be performed by any qualified 737 MAX flight crew (captain and first officer). Specific flight crew training requirements are mandated by the operator’s regulatory agency. Inflight checks of any cabin or galley systems need at least one additional crewmember. An Operational Readiness Flight is to be performed as the final step in Service Bulletin 737-00-1028, and after incorporation of all other mandated 737 MAX RTS service actions.
Update 1 Jul 2020
The FAA and Boeing today completed the certification flight tests on the Boeing 737 MAX. During three days of testing this week, FAA pilots and engineers evaluated Boeing’s proposed changes in connection with the automated flight control system on the aircraft. While completion of the flights is an important milestone, a number of key tasks remain, including evaluating the data gathered during these flights. The agency is following a deliberate process and will take the time it needs to thoroughly review Boeing’s work. We will lift the grounding order only after FAA safety experts are satisfied that the aircraft meets certification standards.
The remaining tasks include:
JOEB Validation & FSB Review – The FAA’s Flight Standardization Board (FSB) and the Joint Operations Evaluation Board (JOEB) which includes international partners from Canada, Europe, and Brazil will evaluate minimum pilot training requirements. The FSB will issue a draft report for public comment addressing the findings of the FSB and JOEB.
Final FSB Report – The FAA will publish a final FSB report after reviewing and addressing public comments.
Final Design Documentation and TAB Report – The FAA will review Boeing’s final design documentation in order to evaluate compliance with all FAA regulations. The multi-agency Technical Advisory Board (TAB) will also review the final Boeing submission and issue a final report prior to a final determination of compliance by the FAA.
CANIC & AD – The FAA will issue a Continued Airworthiness Notification to the International Community (CANIC) providing notice of pending significant safety actions and will publish an Airworthiness Directive (AD) that addresses the known issues for grounding. The AD will advise operators of required corrective actions before aircraft may re-enter commercial service.
FAA Rescinds Grounding Order – This marks the official ungrounding of the aircraft, pending completion by operators of the work specified in the AD, along with any required training.
Certificates of Airworthiness – The FAA will retain its authority to issue airworthiness certificates and export certificates for all new 737 MAX airplanes manufactured since the grounding. The FAA will perform in-person, individual reviews of these aircraft.
Operator Training Programs – The FAA will review and approve training programs for all part 121 operators.
Update 8 Apr 2020
A key test flight of the Boeing 737 MAX has been delayed by a month to May due to the coronavirus crisis. The certification flight, to be overseen by the FAA had been targeted for April. Boeing has been saying that it expected to receive regulatory approval to resume flights on the MAX in mid-2020, and a company spokesman confirmed that timeframe still holds. An FAA spokesman said "work is still ongoing" on the MAX certification. Social distancing policies enacted throughout the United States to address COVID-19 have forced teams from Boeing and the FAA to work remotely and posed challenges for the test flight itself because of the need for closer physical contact. Even after the test flight, other hurdles remain. Officials also need to settle on pilot and crew training requirements for the upgraded MAX, which includes an update to a flight handling system implicated in fatal crashes of Lion Air and Ethiopian Airlines planes.
Update 18 Oct 2019
From the press: "Final Simulator Tests For Boeing 737 MAX Expected To Begin In Early November". If successful, this would suggest that the MAX could be recertified in December and that the type could be back in service by January, subject to crew training requirements and de-mothballing of stored aircraft.
Update 25 Aug 2019
The certification test flight for the changes to Boeing’s 737 MAX flight architecture is now expected to occur in early October. If succussful, a return to service should occur sometime in the fourth quarter of 2019.
Update 5 Aug 2019
Boeing now plan to submit a certification package to the FAA in September, and then expect the MAX to return service early in the fourth quarter.
Update 31 May 2019
Boeing is planning the return to service of the MAX. CEO Dennis Muilenburg has described a disciplined schedule that would start with Boeing teams helping to take about 500 parked 737 jets out of storage. That total includes about 100 newly built aircraft that can't be delivered until the grounding is lifted. They are stored around the Seattle area and on a large Boeing maintenance base in San Antonio. Boeing has two other sites where it could park planes if needed.
Boeing doesn't plan to increase the production rate, dropped from 52 to 42 aircraft per month in April, nor reinstate its financial forecast, until it's clear that its supply-chain is healthy and moving in sync.
CFM International, in a break from its earlier struggles with delays, is starting to deliver turbofans on schedule, Muilenburg said. They are also feeding a pool of spare engines.
Boeing is still responding to questions from the FAA and international regulators. EASA Director Patrick Ky wrote in a letter dated May 27 that EASA will do a separate, in-depth review to examine the 737 Max's entire flight-control system, including the plane's displays, alerts and air-data systems, as well as the aircraft's autopilot function,
"The regulators aren't on the same page," said De Juniac, the IATA chief. "Otherwise they'd have a similar time line, a similar set of measures."
The EASA Position
27 Jan 2021
EASA announce MAX is safe to fly.
The European Union Aviation Safety Agency (EASA) gave its seal of approval for the return to service of a modified version of the Boeing 737 MAX, mandating a package of software upgrades, electrical working rework, maintenance checks, operations manual updates and crew training which will allow the plane to fly safely in European skies after almost two years on the ground.
“We have reached a significant milestone on a long road,” said EASA Executive Director Patrick Ky. “Following extensive analysis by EASA, we have determined that the 737 MAX can safely return to service. This assessment was carried out in full independence of Boeing or the Federal Aviation Administration and without any economic or political pressure – we asked difficult questions until we got answers and pushed for solutions which satisfied our exacting safety requirements. We carried out our own flight tests and simulator sessions and did not rely on others to do this for us.
“Let me be quite clear that this journey does not end here,” he added. “We have every confidence that the aircraft is safe, which is the precondition for giving our approval. But we will continue to monitor 737 MAX operations closely as the aircraft resumes service. In parallel, and at our insistence, Boeing has also committed to work to enhance the aircraft still further in the medium term, in order to reach an even higher level of safety.”
The Boeing 737 MAX was grounded worldwide in March 2019 following the second of two accidents within just six months, which together claimed 346 lives. The root cause of these tragic accidents was traced to software known as the MCAS (Maneuvering Characteristics Augmentation System), intended to make the plane easier to handle. However, the MCAS, guided by only one Angle of Attack (AoA) sensor, kicked in repeatedly if that sensor malfunctioned, pushing the nose of the aircraft downward multiple times. In both accidents, pilots finally lost control of their plane, resulting in a crash with total loss of aircraft.
EASA issued a proposed AD 20-184 cancelling the ‘suspension of flight operations‘ . The following summary is from the PAD:
Reason:
Prompted by two fatal accidents with Boeing 737-8 aeroplanes, EASA issued Emergency AD 2019-0051-E (later revised) to suspend all flight operations of the two affected models. EASA AD 2019-0051R1 allowed non-passenger, non-commercial ferry flights and defined the conditions for such ferry flights.
The results of safety investigations conducted by the authorities of the States where these events occurred, as well as EASA’s own safety review, have confirmed that, with affected FCC OPS and MDS DPC OPS installed, a single erroneous high AOA sensor input to the FCC on an affected aeroplane during manual flight with flaps up may prompt the Manoeuvring Characteristics Augmentation System (MCAS) to input incremental nose down trim. In this scenario, the flight crew may be unable to respond appropriately by applying opposing nose-up stabilizer trim, returning the aeroplane to a trimmed state, and by actuating the stab trim cut-out switches.
This condition, if not corrected, could lead to a stabilizer position that cannot be fully countered with elevator input, possibly resulting in loss of control of the aeroplane.
Prompted by those findings, Boeing developed new OPS for FCC and MDS DPC and issued the applicable SB to provide instructions for OPS in-service installation. Boeing also updated the Airplane Flight Manual (AFM) to introduce new flight crew procedures and limitations, and the applicable flight crew training programme(s), introducing new training to ensure pilot understanding of the MCAS functions, the consequences of introducing the serviceable OPS, and the new ‘Airspeed unreliable’ procedure.
EASA conducted a comprehensive review of the measures proposed by Boeing, including flight testing, and considers that these measures adequately address the above described unsafe condition.
For the reasons described above, this PAD proposes to supersede EASA AD 2019-0051R1, cancelling the ‘suspension of flight operations‘ requirements of that AD. The affected Boeing 737-8 and 737-9 aeroplanes can be returned to service, provided that the required actions proposed in this PAD have been accomplished. To achieve that, this PAD proposes to require that serviceable FCC OPS and serviceable MDS DPC OPS are installed, certain modifications are embodied, including wiring changes, a sensor test is accomplished, and buttons (coloured caps) are installed on the stall warning system’s circuit breakers. This PAD also proposes to require certain changes to the AFM to introduce the new flight crew procedures and limitations, including a prohibition to perform Required Navigation Performance - Authorization Required (RNP AR) approaches, in order to eliminate the identified risk after single failure of an AOA sensor during some RNP AR approaches. This PAD also proposes to require amendment of the EASA-approved Boeing 737 MAX B-737-8/-9 Master Minimum Equipment List (MMEL) Supplement for certain items. Following all these actions, this PAD proposes the accomplishment of an operational readiness flight. Finally, this PAD proposes to prohibit (re)installation of affected FCC OPS and affected MDS DPC OPS, as defined in this PAD.
EASA participated in a Joint Operational Evaluation Board (JOEB) meeting convened by the FAA, also including Agência Nacional de Aviação Civil (ANAC) of Brazil and Transport Canada Civil Aviation (TCCA). This JOEB evaluated the procedural changes and the pilot training proposed by Boeing for the 737-8/-9 (MAX). The JOEB validated Boeing’s proposed training changes, and Boeing embodied them in the Operational Suitability Data for Flight Crew (OSD FC) as part of the EASA Boeing 737 validated type certificate, together with other changes. In particular, and in addition to initial type rating training, differences training from the Boeing 737-600 through 737-900ER series (NG) to the MAX has been improved with the addition of training elements, including new training areas of special emphasis (TASE). In order to support the new training elements, changes which are necessary for Flight Simulation Training Devices (FSTD) are described in the form of dedicated Simulator Data Bulletins (SDB), issued by Boeing Simulator Support. In order to ensure safe operation of the MAX upon return to service, this PAD proposes to require that “return to service” (RTS) training, including ground and flight training in a suitable full flight simulator (FFS), is performed prior to pilots operating the MAX. The RTS training content is documented in a specific Appendix to the B737 OSD FC. Parts of the RTS training can also be done on a Boeing 737 NG FFS, being equivalent to the Boeing 737 MAX FFS for specific manoeuvres, as has been demonstrated during the JOEB process.
EASA has also issued Preliminary Safety Directive (PSD) 20-185, which intends to require holders of an EASA third country operator (TCO) authorisation to implement either all requirements of this EASA AD, or all requirements of FAA AD 2020-24-02, supplemented by the crew training requirements specified in the FAA Flight Standardization Board (FSB) Report for Boeing 737, Revision 17, Appendix 7 (Boeing 737 MAX Special Training for Flight Crews) and the limitation on RNP AR approaches (see Figure 3 of Appendix 1 of this AD), to allow return to service (as related to their TCO authorised operations) of their Boeing 737-8 and 737-9 aeroplanes, when operated under an EASA TCO authorisation into, within or out of the territory to which the EU treaties apply.
When asked about when EASA would unground the MAX, Patrick Ky, the head of the EASA said “We wanted to carry out a totally independent analysis of the safety of this aircraft, so we performed our own checks and flight tests,”. “All these studies tell us that the 737 MAX can return to service. We have started to put in place all the measures,” he said. “It is likely that in our case we will adopt the decisions, allowing it to return to service, some time in January.”
Officials confirmed a draft EASA directive proposing to end the grounding in Europe will be published next week, followed by a 30-day comment period. After finishing touches, that would lead to an ungrounding decision in January.
How long it takes for flights to resume in Europe depends on pilot training and the amount of time it takes airlines to upgrade software and carry out other actions mandated by EASA.
Update 10 Sep 2020
European Union Aviation Safety Agency (EASA) conducted a single flight test in Vancouver, Canada using aircraft 737-7 1E001. The flight lasted 2hr 27min. EASA said “While Boeing still has some final actions to close off, EASA judges the overall maturity of the re-design process is now sufficient to proceed to flight tests,”. Simulator tests were conducted in advance of the flights at a facility at London Gatwick from 1st September 2020..
Update 3 Sep 2019
The European Aviation Safety Agency (EASA) has said it will want to satisfy itself about the MAX's suitability for return to service with no delegation to the FAA.
In a presentation by Patrick Ky, Executive Director of EASA, on 3 Sep 2019 to the European Parliament’s transport committee, the EASA chief showed extracts from a letter he wrote to the FAA on 1 Apr 2019 giving a list of four conditions which would have to be met before EASA would allow the MAX to return to service:
Ky noted that the FAA now finds itself in a “very difficult situation”, indicating that the hierarchy between certification authorities and the US agency may be forever changed, saying, “It is very likely that international authorities will want a second opinion, or a further opinion … It was not like this a year ago.”
The presentation was not exclusively about the MAX and these slides deal with other non-MAX issues such as EASA Strategic Priorities etc
Title Page (Slide 6)
Lion Air accident (Slide 7)
Ethiopian accident (Slide 8)
Decision to ground / ban (Slide 9)
Preliminary information On the Contributing factors (Slide 10)
Return to Service - EASA conditions (Slide 11)
1. Design changes proposed by Boeing are EASA approved (no delegation to FAA)
2. Additional and broader independent design review has been satisfactorily completed by EASA
3. Accidents of JT610 and ET302 are deemed sufficiently understood
4. B737 MAX flight crews have been adequately trained
EASA Design Review (Slide 12)
Objective: to ensure that no similar weaknesses in the design are present in the other (safety critical) areas of the 737 MAX design.
Activities are being carried out on the Flight Control System and all associated functions/systems including but not limited to the following: displays, alerting system, autopilot and air data system.
- Review of Functional Hazard Assessments and Safety Analysis
- Review of Development Assurance process - Review of Flight Controls and Autopilot architecture and logics
- Review of Human Factors aspects
- Review of the methodology applied for the assessment of the Crew Training needs
EASA activities (Slide 13)
EASA Findings (Slide 14)
Significant technical issues:
- Lack of exhaustive monitoring of the system failures resulting in a stabiliser runaway
- Too high forces needed to move the manual trim wheel in case of a stabiliser runaway
- Too late disconnection of autopilot near stall speed (in specific conditions)
- Too high crew workload and risk of crew confusion in some failure cases, especially Angle of Attack single failure at take-off
Findings communicated to Boeing and FAA in July 2019
Latest Status (Slide 15)
Of note here is that EASA states that there is "still no appropriate response to Angle of Attack integrity issues".
Next major milestones (Slide 16)
Safety assessment of the new design changes proposed by Boeing, including operational procedures
Human factor evaluation and functional tests of the new software
Flight tests on a modified B737 max [one full week - at Boeing Flight Test Center]
MCAS operations (nominal behavior)
Flight without MCAS (including high speed turns and stall)
Scenario of stabiliser runaway (uncommanded MCAS activation, manual trim wheel forces)
Approach to stall with autopilot engaged
Crew Training requirements, in particular using Computer Based Training or Simulator
Coordination with EASA Member States on Return to Service actions
MMEL was published 10 April 2020. It incorporated the following changes following the types redesign after the MCAS accidents.
The Transport Canada Position
18 Jan 2021 - "Transport Canada issued an Airworthiness Directive CF-2021-02 for the Boeing 737 MAX which outlines the required modifications to be made to the aircraft prior to a return to service in Canadian airspace. This concludes the department’s review of the aircraft.
As part of Transport Canada’s independent review process, the department’s civil aviation certification and flight safety experts were instrumental in guiding the aircraft design changes. Additionally, the department has gone even farther by introducing unique Canadian measures to further enhance the safety of the aircraft.
In addition to all reviews, and to provide additional assurances that all measures are in place, an Interim Order that clearly indicates Transport Canada’s expectations and requirements for additional training for crew members was also issued for operators. It is complementary to the design and maintenance requirements of the Airworthiness Directive.
The Transport Canada AFM Appendix also includes a change to the ALT DISAGREE alert procedure that differs from the FAA AD 2020-24-02, effective 20 November 2020. Transport Canada requires the inclusion of a step stating that the aircraft does not meet reduced vertical separation minimum (RVSM) operational requirements and provides additional guidance to the crew."
The TC AD includes the following requirements for the stick shaker:
"During dedicated simulator testing, Transport Canada test pilots found that, following the activation of the stick shaker, the constant noise and vibration was a significant impediment to the safe operation of the aeroplane for the remainder of the flight. Transport Canada therefore requires that the AFM be modified to add a means to disable a nuisance stick shaker. The disabling of the stick shaker also improves the crew’s recognition of the stall warning and disables an incorrect activation of the elevator feel shift. As the means to disable the nuisance stick shaker is through the use of circuit breakers (CBs), Transport Canada is mandating the incorporation of Boeing SB 737-27-1320. This SB requires the addition of coloured caps on CBs for the stick shaker, to allow for ease of identification. The step, to disable a nuisance stick shaker within the airspeed unreliable procedure, is included in the Transport Canada AFM Appendix that is an integral part of the FCC operational program software (OPS), software version P12.1.2, modification."
17 Dec 2020 - Federal Transport Minister Marc Garneau said “Today is the validation, which means that we recognize the modifications that have been made to fix the problem with the Max 8, However, there’s still another step to take, and that will be done in January, when we will, as Canada, emit what we call an airworthiness directive.”
Transport Canada will be mandating that a mechanism be made available to crew to inhibit the stick shaker if they have determined that it is operating when it should not be. EASA similarly mandated that the appropriate circuit breakers must be marked with red collars.
Changes to the 737 MAX MMEL
Revision 2 to the MAX -8 & -9
ATA 22 Autoflight
Deleted dispatch option 22-10-01B. Autopilot Systems (Both Inoperative) – FAA will no longer allow dispatch with both A/P inoperative. Because The Speed Trim System uses the FCCs.
Deleted item 22-10-02 Autopilot Disengage Aural Warning System - FAA will no longer allow dispatch with this inoperative. Because the Aural warning is now considered to be of similar importance to both disengage lights for timely flight crew.
alerting of autopilot disengagement
Deleted item 22-10-03 STAB OUT OF TRIM Light – FAA will no longer allow
dispatch with this inoperative. Because FCC 12.1.3 will generate the STAB OUT OF TRIM light below 30 knots ground speed to prevent erroneous dispatch for the next flight due to latent loss of one STS channel.
Deleted item 22-11-01 Speed Trim Function – FAA will no longer allow dispatch with this item inoperative. Because The Speed Trim System (STS) provides speed and pitch stability augmentation.
Deleted item 22-11-02 SPEED TRIM FAIL Light – FAA will no longer allow dispatch with this light inoperative. Because the AoA's are now compared and exceeding the comparison threshold will generate the SPEED TRIM FAIL light and inhibits both MCAS and Speed Trim operation
for the remainder of the flight.
Added proviso to dispatch option 22-11-08-01A ASA Autopilot (A/P) Disengage Light (One Inoperative) – FAA will require that the autopilot disengage aural warning system operates normally
Deleted dispatch option 22-11-08-01B Autothrottle (A/T) Disengage Light (Both Inoperative) – FAA requires that operators comply with operational requirements contained in MMEL 22-31-01 (Autothrottle system)
Added proviso to dispatch option 22-11-10A Control Wheel Autopilot Disengage Switches (One Inoperative) – FAA will require that the Mode Control Panel autopilot DISENGAGE bar also operates normally. Because the two switches can disengage both FCCs.
Deleted dispatch option 22-11-10B Control Wheel A/P Disengage Switches (Both Inop) - FAA will no longer allow dispatch with this inoperative. Because the two switches can disengage both FCCs.
ATA 27 Flight Controls
Deleted item 27-41-01 Control Wheel Trim Switch – FAA will no longer allow dispatch with one of these switches inoperative. Because the NNC for Runaway Stabilizer, which requires use of the control wheel trim switches, is now considered an emergency procedure.
Proposed Changes to the 737CL/NG MMEL
Boeing has been requested by the FAA to review the 737CL/NG MMEL for changes comparable to those being implemented into the 737 MAX MMEL for return into revenue service. As a result, Boeing has submitted the following changes to the FAA for Revision 61 of the 737CL/NG MMEL:
1. 737CL/NG MMEL Item 22-01-01 Control Wheel Autopilot Disconnect Switches - relief split into two sub-items, 22-01-01-01 for 737CL airplanes without Autopilot DISENGAGE Bar and 22-01-01-02 for 737CL airplanes with Autopilot DISENGAGE Bar and 737NG airplanes as follows:
a) Option 22-01-01-01A Control Wheel Autopilot Disconnect Switches (One Inoperative) - FAA will allow Control Wheel Autopilot Disconnect Switch to be inoperative on non-flying pilot's side.
b) Option 22-01-01-01B Control Wheel Autopilot Disconnect Switches (Both Inoperative) - FAA will require that autopilots are not used.
c) Option 22-01-01-02A Control Wheel Autopilot Disconnect Switches (One Inoperative) - FAA will require that the Mode Control Panel autopilot DISENGAGE bar also operates normally.
d) Option 22-01-01-02B Control Wheel Autopilot Disconnect Switches (Both Inoperative) - FAA will require that autopilots are not used.
2. 737CL/NG MMEL Item 22-02-01A Autopilot (A/P) Disengaged Light (One Inoperative) with aural warning system - FAA will require that the autopilot disengage aural warning system operates normally.
3. 737CL/NG MMEL Item 22-02-01B Autopilot (A/P) Disengaged Light (One Inoperative) without aural warning system - Added dispatch relief item. Except for ER operations, the FAA will require that autopilots are not used.
5. 737CL/NG MMEL Item 22-02-02 Autopilot Disengaged Aural Warning System - FAA will prohibit use of the autopilots (except for ER operations) when the aural warning system is inoperative and reduce the required repair interval from 10 days to 3 days.
6. 737CL/NG MMEL Item 22-09 SPEED TRIM FAIL Light System - FAA will no longer allow dispatch with this light inoperative (Item Removed).
7. 737CL/NG MMEL Item 22-10 Speed Trim System - FAA will no longer allow dispatch with this item inoperative (Item Removed).
8. 737CL/NG MMEL Item 27-09 Control Wheel Trim Switch Systems - FAA will no longer allow dispatch with one of these switches inoperative (Item Removed).
The document will be posted until 01 Jan 2020, after which all comments will be evaluated and reconciled before the MMEL revision is published. Boeing has been notified by the FAA that the final publication date for the 737CL/NG MMEL will not be linked to the 737 MAX MMEL publication, nor will operators be expected to revise their individual MELs at an accelerated time requirement that will likely be imposed on the 737 MAX.
EASA 737NG MMEL Revision 5 is expected to incorporate the same changes that were made to FAA MMEL Revision 61. This document is being prepared and will be sent to EASA for their review. EASA approval for MMEL Revision 5 is expected to be subsequent to the FAA's publication of their MMEL revision.
Post Grounding Issues
16 Jun 2021 - The FAA issued a Continued Airworthiness Notification to the International Community (CANIC) "requiring functional checks at certain intervals to the digital flight control system, stabilizer trim, and the primary and secondary aisle stand stabilizer." The three repetitive inspections are to be done during existing maintenance programs, the FAA said, "to ensure the continued functioning of certain systems throughout the life of the airplane."
The FAA also issued a notice on Wednesday called a Continued Airworthiness Notification to the International Community (CANIC) "to highlight the importance of these inspections to other international regulators and to operators outside the United States."
The FAA said the directive is necessary because a "potential latent failure of a flight control system function" if combined with "unusual flight maneuvers or with another flight control system failure" could result in reduced controllability of the airplane.
The directive makes mandatory instructions released by Boeing in December that recommend aircraft with over 6,000 flight hours be subject to specific electronic checks.
Legal Action Against the Boeing Technical Pilot
The FINAL COMMITTEE REPORT: BOEING 737 MAX in Chpter 7 Boeing 737 MAX Pilot Training details how the former Boeing 737 MAX Technical Pilot, Mark Forkner’s hard sell tactics to dissuade airlines from simulator training was the result of an implied message from Boeing management to discourage such training because of the threat it posed to the marketing strategy and ultimately the profitability of the 737 MAX program. Extracts of the messages he sent on the subject are contained within the report. (available here).
24 Mar 2022 - Chair DeFazio Statement on Mark Forkner Verdict
Chair of the House Committee on Transportation and Infrastructure Peter DeFazio (D-OR) issued the following statement after the acquittal of former Boeing 737 MAX chief technical pilot Mark Forkner. “As I have said many times, Boeing needs to be held accountable. Criminal prosecution is not the only form that can take. FAA should be conducting its own investigation to determine if civil enforcement is warranted. FAA’s lack of action on this front is stunning, and that’s why we’ve asked the Department of Transportation’s Inspector General to review how FAA has dealt with Boeing’s questionable conduct.” In February, DeFazio and Chair of the Subcommittee on Aviation Rick Larsen (D-WA) requested the U.S. Department of Transportation’s Office of Inspector General review FAA’s oversight of Boeing’s apparent 737 MAX misconduct. Read more about the letter here.
23 Mar 2022 - Former Boeing 737 MAX technical pilot found not guilty of wire fraud in Texas trial
Mark Forkner, a former Boeing employee who was the lead technical pilot during the development of the 737 MAX, on Wednesday was found not guilty by a Texas jury on four counts of wire fraud to deceive officials on the aircraft’s performance prior to flight. The Justice Department originally charged Forkner with two counts of fraud involving aircraft parts in interstate commerce and four counts of wire fraud; a judge dropped the two counts involving the aircraft parts in Feb 2022.
Forkner would have faced a maximum penalty of 20 years in prison on each count of wire fraud. In October, DOJ prosecutors alleged that Forkner deceived his counterparts in the FAA’s aircraft evaluation group about the aircraft’s performance, withholding pertinent information about MCAS. The DOJ stated that Forkner “provided the agency with materially false, inaccurate, and incomplete information about a new part of the flight controls for the Boeing 737 MAX called the Maneuvering Characteristics Augmentation System (MCAS),” and “Because of his alleged deception, a key document published by the FAA ... lacked any reference to MCAS.”
According to media reports of the trial, prosecutors said that Forkner deceived Stacey Klein, his FAA counterpart, in order to save Boeing money so pilot crews wouldn’t have to train to a new software standard in the cockpit. Defense attorneys argued Forkner didn’t knowingly lie to Klein, who approved pilot training.
09 Feb 2022 - U.S. Judge Dismisses Two Charges Against Former Boeing 737 MAX Technical Pilot
A U.S. judge on Tuesday dismissed two charges against a former chief technical pilot for Boeing Co accused of deceiving federal regulators evaluating the company's 737 MAX jet, but rejected a request to dismiss the other four counts. U.S. District Judge Reed O'Connor in Texas granted part of the request of lawyers for former Boeing technical pilot Mark Forkner, dismissing two fraud counts alleging Forkner made materially false communications concerning a key airplane software feature called Maneuvering Characteristics Augmentation System (MCAS). MCAS is a software feature designed to automatically push the airplane's nose down in certain conditions. It was tied to the two 737 MAX crashes over a five-month period in 2018 and 2019 that killed 346 people and led to the Federal Aviation Administration (FAA) grounding the plane for 20 months, an action lifted in November 2020. O'Connor ruled Tuesday the two charges could not proceed because they must involve a tangible airplane part -- rather than the MCAS software feature. "MCAS is intangible computer code in the aircraft’s flight control software," O'Connor wrote. "MCAS is not an 'aircraft part.'" O'Connor rejected a request to dismiss the other four counts which allege wire fraud. Forkner was indicted in October on charges of scheming to defraud Boeing's U.S.-based airline customers to obtain tens of millions of dollars for Boeing. The case is currently set for trial in early March. In January 2021, Boeing agreed to a $2.5 billion deferred prosecution agreement with the Justice Department over the MAX crashes, which cost Boeing more than $20 billion. The Justice Department said on Tuesday in a separate filing that it has not charged Forkner "with causing the crashes of Lion Air Flight 610 or Ethiopian Airlines Flight 302 and that it does not intend to argue that he caused them."
14 Oct 2021
A former chief technical pilot for Boeing Co was charged with fraud on 14 Oct 2021 for deceiving federal regulators evaluating the company's 737 MAX jet, hindering the ability to protect airline passengers and leaving "pilots in the lurch," according to the U.S. Justice Department.
"In an attempt to save Boeing money, Forkner allegedly withheld critical information from regulators," said Chad Meacham, the acting U.S. attorney for Northern Texas. "His callous choice to mislead the FAA hampered the agency's ability to protect the flying public and left pilots in the lurch, lacking information about certain 737 MAX flight controls."
Mark Forkner, 49, was indicted by a grand jury in Texas on six counts of scheming to defraud Boeing's U.S.-based airline customers to obtain tens of millions of dollars for Boeing, the government said.
The charges of two counts of fraud involving aircraft parts in interstate commerce and four counts of wire fraud could carry up to 100 years in prison should he be convicted.
Other legal actions against Boeing
19 Jan 2023 - U.S. judge orders Boeing arraigned on MAX fraud charge
A federal judge on Thursday ordered Boeing Co to appear in court on Jan. 26 to be arraigned on a 2021 felony charge after families of those killed in two fatal crashes objected to a 2021 plea deal. Boeing won immunity from criminal prosecution as part its $2.5 billion January 2021 Justice Department deferred prosecution agreement over a 737 MAX fraud conspiracy charge related to the plane's flawed design.
The families argued that the Justice Department "lied and violated their rights through a secret process," and asked U.S. District Judge Reed O'Connor to rescind Boeing's immunity from criminal prosecution. O'Connor, of the Northern District of Texas, in Fort Worth, ruled in October that people killed in two Boeing 737 MAX crashes are legally considered "crime victims," and family members had urged him to require Boeing to be legally arraigned on the felony charge.Boeing and the Justice Department declined comment.
O'Connor directed any lawful representatives of those that identified as "crime victims" who intend to appear to be heard at the proceedings must provide notice and "an appropriate person appear at the arraignment on behalf" of Boeing. The crashes in 2018 and 2019 in Indonesia and Ethiopia, which cost Boeing more than $20 billion, led to a 20-month grounding for the best-selling plane and prompted the U.S. Congress to pass legislation reforming airplane certification.
Both Boeing and the Justice Department oppose reopening the deferred prosecution agreement, which included $500 million in victim compensation, a $243.6 million fine and $1.7 billion in compensation to airlines. The Justice Department said in 2021 "misleading statements, half-truths, and omissions communicated by Boeing employees to the (Federal Aviation Administration) impeded the government’s ability to ensure the safety of the flying public." The Justice Department said in a November court filing it did not oppose an arraignment for Boeing but opposes undoing the agreement, saying it "would impose serious hardships on the parties and the many victims who have received compensation." Boeing said in November it opposes any effort to reopen the agreement, calling it "unprecedented, unworkable, and inequitable" and noted it has been complying with the agreement for nearly two years.
In September, Boeing agreed to pay $200 million to settle civil charges by the Securities and Exchange Commission it misled investors about the MAX. Polish national airline PLL LOT in October asked O'Connor to declare it a crime victim in the MAX criminal case, a move that could make the airline eligible for significant compensation.
MCAS Media Videos
The following are a selection of videos and explanations of MCAS issues from the media:
BBC News, 4 Apr 2019
In this video I explain and demonstrate a stall and then later the effect of MCAS trimming the stabiliser down and how it would be unexpected by crew.
60 Minutes Australia, Published on 5 May 2019.
Liz Hayes investigates the disaster of Boeing’s 737 MAX jetliner. Why two supposedly state-of-the-art and safe planes crashed killing 346 people; why pilots now fear flying the 737 MAX; & whether Boeing could have averted the catastrophes.
In this video I discuss and try to simulate the effect of an unanunciated AoA disagree (ie airspeed unreliable) and MCAS activation shortly after take-off. Note that due to the considerable editing down process this video does not show the recall actions and is in no way intended to be a demonstration to flight crew of how to handle such a scenario. It has been edited by non-aviation professionals for the consumption of the general public.
BBC Panorama, Published on 29 Jul 2019.
The Boeing 737 Max was set to dominate the skies, but two deadly crashes have left the aircraft grounded and the company in crisis. Both flights were forced down by software specially designed for the new aircraft. Reporter Richard Bilton investigates the plane’s fatal flaws and asks whether Boeing should have done more to protect passengers.
737 MAX - MCAS
