Boeing knew about 737 MAX problems before Indonesia crash

Saul Bowman
Мая 7, 2019

The US plane manufacturer did not disclose the information to the Federal Aviation Administration (FAA) for 13 months until after Indonesia's Lion Air plane crash in October and insisted the missing display did not represent a safety risk, according to a Boeing statement on Sunday.

Boeing also said there is an "AOA disagree alert" that would work only when aircraft have been procured with additional cost paying the optional feature.

But the statement released on Sunday described a troubling timeline that shows how long some at the company were aware of the problem before finally deciding to act.

- A number of countries have banned Boeing's 737 MAX 8 medium-haul workhorse jet from their airspace in response to the Ethiopian Airlines crash that killed all 157 people on board. Two planes, Lion Air Flight 610 and Ethiopian Airlines Flight 302, crashed as the result of faulty "angle of attack sensors".

The growing scrutiny could pose new challenges to Boeing's efforts to shore up confidence in the 737 MAX, solicit regulatory support around the globe and get the MAX fleet, grounded after the second crash, flying again.

Boeing's statement notes that in 2017, soon after 737 MAX deliveries started, Boeing engineers detected that the 737 Max display system software was not exactly meeting the AOA Disagree alert requirements. Boeing did not originally reveal the warning only operated properly on planes flown by airlines that had purchased an optional AOA indicator.

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Boeing's statement makes it evident that despite knowing the flaw, Boeing's engineers chose to go slow with the logic that "the existing functionality was acceptable until the alert and the indicator could be delinked in the next planned display system software update". In the statement meant to manage the fallout, Boeing stated that it detected an issue in the 737 Max's software back in 2017, but after an internal vetting process, the aircraft was of acceptable flight worthiness.

The FAA said the issue was "low risk", but said Boeing could have helped to "eliminate possible confusion" by letting it know earlier. But its engineers discovered that the sensor worked only with a separate, optional safety feature.

Immediately following the company's reiteration that it did not merit action in 2017, Boeing confirmed that it was brought up again in 2018 and a Safety Review Board (SRB) was convened to "consider again whether the absence of the [safety] alert from certain 737 Max flight displays presented a safety issue". Boeing also broke the news of the glitch to Max operators such as Southwest Airlines in the aftermath of the initial crash.

Boeing maintains that the 737 Max was safe to fly even without the alert, which it says provides only "supplemental information".

The Ethiopian pilots, who after the previous crash would have been keenly aware of MCAS, seem to have realized that system was the problem reasonably quickly and tried to follow Boeing's recommended checklist of procedures to handle it, though they still were not able to control the plane.

Boeing also did not flight test what would happen to the MCAS system if the single AOA sensor failed, CNN previously reported.

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