At this point, I think that we need to seriously consider filing criminal charges against senior figures at Boeing aircraft, and maybe a few FAA officials.
Six years before the crew flying a Lion Air Boeing 737-8 reacted to an emergency in a very different way than Boeing assumed pilots would, something similar happened within Boeing’s walls.
During simulator sessions to evaluate a new flight control law’s potential hazards, Boeing test pilots took more than 10 sec. to diagnose and correct a runaway stabilizer. The session caused one employee to wonder whether pilots of the newest 737 family member, dubbed the MAX series for marketing purposes, needed more information to diagnose the hazard. A second employee who flew the simulator scenario responded that more analysis was needed.
- New U.S. Congress report highlights issues with pilot-aircraft interface during 737 MAX development
- Long-accepted norms for predicting how pilots react are now being challenged
- Boeing did not deem the issues significant risks and minimized how much information pilots received
Boeing ultimately determined that MAX pilots would react within seconds in such scenarios—and that the new control law, the Maneuvering Characteristics Augmentation System (MCAS), could not create new or more severe hazards. The assumptions were not challenged by regulators.
The similar accident sequences of Lion Air Flight 610 (JT610) in October 2018 and Ethiopian Airlines Flight 302 (ET302) less than five months later—both caused by unneeded MCAS activations—showed that Boeing and the FAA were wrong. Now Boeing, the FAA and others point to the accidents as hard, painful evidence that generally accepted assumptions used to evaluate how pilots will react during inflight emergencies need revamping (AW&ST Oct. 14-27, 2019, p. 18).
But newly revealed information collected by U.S. lawmakers investigating the 737 MAX development raises questions about how Boeing handled hazard assessments and whether it ignored evidence that showed MAX pilots would need more help than they were given.
“Multiple Boeing [employees] failed to inform the FAA that Boeing had discovered early on in the MAX program that it took one of its own test pilots more than 10 sec. to respond to an uncommanded activation of MCAS in a flight simulator, a condition the pilot found to be ‘catastrophic,’” states a report released by the House Transportation and Infrastructure (T&I) Committee. “This should have called into question Boeing’s assumptions about pilot response times. It did not.”
The committee’s view is based in part on email messages about the 2012 simulator sessions included among thousands of pages of documents Boeing and the FAA provided in response to lawmakers’ requests during the 18-month investigation.
In a second run-through, “the reaction time was long,” greater than 10 sec., the employee wrote, before the cutout switches were toggled, stopping the MCAS-triggered automatic nose-down inputs.
“Do you think that with pilot training/knowledge of the system there will be a sufficiently quick response to the [stabilizer] runaway . . . ?” the employee asked.
“I would like to take a look at how much time there is between a hazardous assessment and a catastrophic assessment,” a second employee responds.
The T&I Committee report does not explain what happened next. Testifying before the committee in October 2019, former Boeing Commercial Airplanes chief engineer John Hamilton told lawmakers that subsequent simulator runaway-stabilizer scenarios showed “the typical reaction time was 4 sec.”
Boeing also concluded that a reaction of 10 sec. or longer must be categorized as “catastrophic,” which the FAA’s large aircraft system design and analysis certification guidance defines as “failure conditions which would prevent continued safe flight and landing.” The 10-sec. parameter was listed in 737 MAX internal design parameters, or “coordination sheets,” right through the 737-8’s March 2017 certification.
“Every new buzzword represents a company and airline cost via changed manuals, changed training, changed maintenance manuals,” says a 2013 Boeing internal “problem statement” document discussing how the MCAS should be categorized. “Recommended action: investigate deletion of MCAS nomenclature and cover under ‘revised speed trim.’”
While the MCAS name did not disappear, it was downplayed.
A 2014 Boeing presentation prepared for Southwest Airlines and included in the committee’s report discusses the MCAS, underscoring that the system was not kept a secret. But Boeing opted not to include it in flight crew operations manuals, so most line pilots did not realize it existed.
Meanwhile, Boeing determined that the MCAS’ original authority was not enough.
Developed in response to 2011 wind-tunnel testing that quantified the effects of the MAX’s CFM Leap 1B engines on the aircraft’s aerodynamics as a requirement to ensure the new model handled like its predecessors in certain rare flight profiles, the MCAS’ original authority covered high-speed scenarios such as wind-up turns.
Adding the low-speed authority meant that the MCAS could direct an aircraft from wings-level to full aircraft nose down in two cycles or an elapsed time of 25 sec., counting a 5-sec. pause between activations.
The day before JT610 went down, a different crew flew the same aircraft and experienced a similar situation (AW&ST Nov. 11-24, 2019, p. 23). While the crew, aided by a pilot flying in the jumpseat, toggled the stabilizer trim cutout switches and eventually landed safely, their reaction did not match Boeing’s assumptions. This flight and the two accident flights are the only three in-service reports of the MCAS triggering unneeded stabilizer inputs.
The T&I Committee’s 238-page report cites Boeing’s “disturbing pattern of technical miscalculations and troubling management misjudgments” as well as “numerous oversight lapses and accountability gaps by the FAA” as playing a “significant” role in the two accidents. The pilot-response issue is part of a long list that includes designing the MCAS to be activated based on one AOA sensor’s input and deciding, with FAA approval, to keep any discussion of the MCAS out of pilot flight manuals.
“Our report lays out disturbing revelations about how Boeing . . . escaped scrutiny from the FAA, withheld critical information from pilots, and ultimately put planes into service that killed 346 innocent people,” says committee Chair Pete DeFazio (D-Ore.). “What’s particularly infuriating is how Boeing and FAA both gambled with public safety in the critical time period between the two crashes.”
They knew. Their own pilots, who knew the plane like the back of their hands, could not reliably react in under 10 seconds.