Boeing revealed Sunday that the company knew about the issues with its 737 Max airplanes for months before the two deadly crashes that killed almost 350 people.
All 737 Max planes were grounded in March after the second crash of the model in just a few months killed 158 people in an Ethiopian Airlines flight.
Indications are out that aerospace manufacturer Boeing was very much aware of the problems with the 737 Max aircraft long before the 2018 Lion Air crash in Indonesia.
By becoming optional, the alert had been treated in the same way as a separate indicator showing raw AOA data, which is seldom used by commercial pilots and had been an add-on for years.
Boeing's statement makes it evident that despite knowing the flaw, Boeing's engineers made a decision 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".
Yet, after a review, Boeing's engineers decided not to immediately correct the problem, concluding that "the existing functionality was acceptable until the alert and the indicator could be delinked in the next planned display system software update".
It is not clear whether having the warning light would have prevented either the Lion Air crash or the March 10 crash of an Ethiopian Airlines Max near Addis Ababa. But the new disclosure raises questions about how forthright the company has been about issues with the planes.
"However, Boeing's timely or earlier communication with [airlines] would have helped to reduce or eliminate possible confusion", the spokesman said in a emailed statement emailed to Associated Press.More news: Enes Kanter's body barely survived Blazers-Nuggets marathon
Erroneous data from a sensor responsible for measuring the AOA or the angle at which the wing slices through the air is suspected of triggering a flawed piece of software that pushed the plane downward in two recent crashes.
Boeing contends the alert function was not necessary for the safe operation of the airplane.
Disagree alerts would notify pilots whether a sensor is malfunctioning or not.
Boeing briefed the FAA's Seattle aircraft certification office in November, and the information was forwarded to the agency's Corrective Action Review Board for evaluation, an FAA representative said Sunday.
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. Tajer said the American pilots were told in the meeting that on the flight deck of their 737 MAXs, the AOA disagree light would have lit up on the ground and so, because that's a "no-go item", the plane wouldn't even have taken off.
Then, one week after the Lion Air crash on October 29, Boeing added a line in an FAA airworthiness directive that said the disagree light was optional.
Before the Max returns to service, Boeing plans to issue a software update that will allow the AOA disagree light to operate as a standalone feature.
The 737 Max has been grounded around the world for nearly eight weeks.
Boeing said it also told the FAA that company engineers had identified the issue in 2017, along with the findings from their internal review process.