Boeing Faulted, Not the Pilots: Two Prelim MAX Reports Released


Both the Ethiopian aviation authority and the U.S. House of Representatives have unloaded on Boeing this week in dual preliminary reports published just short of the one-year anniversary of the second MAX crash that set its grounding in motion. The Ethiopian report largely exonerated Flight 302’s flight crew while the House report laid out five key investigative themes that included Boeing’s production pressures, faulty assumptions made in development of the MAX, a “culture of concealment” inside Boeing, conflicts of representation and the influence Boeing held over the FAA in the certification process.

In the Ethiopian preliminary report, the investigators say little about the actions of the crew, which was composed of a 29-year-old captain with 8,122 total hours, 1,417 as PIC of the 737-800 series and 103 hours in the MAX, and a first officer with 361 total hours and 207 in the B-737, all the MAX variant. While most of the narrative is well known, the Ethiopian investigators focused on the mechanical condition of the MAX and information from the flight-data and cockpit-voice recorders. Although MCAS activation was not a tracked parameter in the flight data, its actions can be determined by other sources; the report confirms that MCAS activated after the failure of one angle-of-attack probe. The crew, fighting nose-down pitch trim with around 94 pounds of force for much of the flight, momentarily turned off the electric pitch trim (disabling MCAS) but was unable to manually put in enough trim to stabilize the flight. When the crew reenabled the electric pitch trim system, MCAS went back to work and continued to drive nose-down trim.

Among the findings in the Ethiopian report, “The difference training from B737NG to B737 MAX provided by the manufacturer was found to be inadequate. The AOA Disagree message did not appear on the accident aircraft as per the design described on the flight crew operation manual. [The] AOA failure detection feature of the [air-data computer] did not detect the erroneous AOA from the left AOA sensor because it only considers the value to be erroneous when the AOA value is outside the physical range.” As a result, the pilot was never given speed warnings on his primary flight display. In addition, the Ethiopian authorities stated that “[The MCAS design [relies] on single AOA inputs made it vulnerable to undesired activation.” The report concludes that “specific failure modes that could lead to uncommanded MCAS activation, such as an erroneous high AOA input to the MCAS, were not simulated as part of the functional hazard assessment validation tests. As a result, additional flight deck effects (such as IAS DISAGREE and ALT DISAGREE alerts and stick shaker activation) resulting from the same underlying failure (for example, erroneous AOA) were not simulated and were not documented in the stabilizer trim and auto flight safety assessment.”

For its part, the House Transportation Committee concluded that “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.”

“Our Committee’s investigation will continue for the foreseeable future, as there are a number of leads we continue to chase down to better understand how the system failed so horribly. But after nearly 12 months of reviewing internal documents and conducting interviews, our Committee has been able to bring into focus the multiple factors that allowed an unairworthy airplane to be put into service, leading to the tragic and avoidable deaths of 346 people,” Chair Peter DeFazio, D-Ore., said. “As we release this report to lay out our findings to date, my thoughts are with the families of the victims. Our search for answers continues on their behalf and for everyone who boards an airplane. The public deserves peace of mind that safety is always the top priority for everyone who has a role in our aviation system.”

Boeing and the airlines generally seem to feel that the MAX will be cleared to fly in June or July, with mothballed aircraft returning to service over the summer. What the summer travel season looks like will depend on progression of the coronavirus (COVID-19) epidemic. Already, airlines around the world are cutting flight schedules as customers stay home, and management is carefully weighing the impact of bringing new aircraft into the fleet at such a time. It has been suggested that just as Boeing needs airlines to accept delivery of the MAX, they’ll not be in a financial position to do so. Boeing stock, which had begun a partial recovery from to almost $350/share in early February, fell alongside the overall stock market to $220/share today amid news that it’s expected to announce no new sales in January. Boeing’s share slide is currently outpacing the general market concern, however.

Marc Cook
KITPLANES Editor in Chief Marc Cook has been in aviation journalism for more than 30 years. He is a 4000-hour instrument-rated, multi-engine pilot with experience in nearly 150 types. He’s completed two kit aircraft, an Aero Designs Pulsar XP and a Glasair Sportsman 2+2, and currently flies a 2002 GlaStar.

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  1. Couple of items missed with the House report. Chairman Mr DeFazio needs to re-examine the FAA funding authorization bill calling for more industry designated engineering persons. After all his committee passed that bill. Also how about allowing Boeing to buy out McDonnell-Douglas, creating a monopoly of American airplane companies producing airliners along with the “too big to fail” situation. The hypocrisy from congressional committees running rampant again!

    • My exact same thoughts. Wasn’t it Congress that passed the ODA? It looks like no one is taking responsibility. I don’t feel any reassured.

  2. Ethiopian aviation authority has been smoking something. MCAS is bad, no doubt about it. A captain who leaves takeoff power applied to doom is even worse.

  3. Boeing in deep dodos and it is not going to get better any time soon, if at all. Be prepared for Airbus to pick over the carcass!!

    • That’s also a scary thought. Airbus can’t pick up the slack either. We know how these companies operate and their business models are so fragile with little to no back up plans. That’s the problem with monopolies. When one of two fall, the other carries the burden of the weight without being able to handle it or forsee it.

  4. Well of course the Ethiopians put all the blame on Boeing and not their pilots!. The right seat guy with 361 hours? Give me a break!!! Regardless of the Boeing faulty systems, other pilots with both experience and common sense reacted properly to similar malfunctions.

  5. Odd that the pilots were not fully trained and didn’t respond correctly to runaway trim. Years ago a B52 crashed when the pilot thought they were in a high speed dive and they were stalled with full nose up trim and the wheel yanked aft. I guess you can have lots of training and not understand how an airplane flys.

  6. “…a first officer with 361 total hours and 207 in the B-737, all the MAX variant.”
    So, a whopping 154 hours that were NOT in a Boeing? How/where/when did this guy acquire a commercial pilot certificate? Seriously. Sounds like he was put in the right seat of a passenger-carrying commercial airliner, with a grand total of 150 hours of flight experience. Ab Initio uber alles? THAT must have been Boeing’s fault, too.

  7. I find it interesting that the Ethiopian report is totally silent about the fact that the maintenance crew changed out the AOA sensor, which was written up by the previous flight crew who had a similar problem but managed to take corrective action. The maintenance crew installed a different sensor that had been improperly overhauled and failed to test it to see if it was actually working (which it was not). I guess that is Boeing’s fault too.

    • No, that was Lion Air. The Ethiopian plane is believed to have been working perfectly until after it became airborne. Then it appears that the AOA vane was struck by either a bird or a piece of debris as the plane climbed through about 50 feet.

      • Oops, you’re right. My Mistake. I guess I should keep my hands off the keyboard until after my second cup of coffee!

  8. It is a shame that the comments above will not be reflected to the proper authorities in Congress and FAA for public dissemination. The public NEVER hears the whole story!