Boeing nearing 737 Max fleet bulletin on AoA warning after Lion Air crash
This is a breaking story and will be updated.
Boeing will issue a service bulletin to 737 Max operators worldwide warning operators that the jet’s angle of attack sensor can produce erroneous indications causing the single-aisle jet to enter an aggressive dive, according to a senior industry official familiar with the action.
The bulletin comes after a newly-delivered Lion Air 737 Max crashed off the coast of Indonesia on October 29, killing all aboard. The bulletin is expected to say that Indonesian air safety officials have said that Lion Air flight 610 experienced erroneous angle of attack input.
According to the official familiar with the bulletin, Boeing warns operators that the angle of attack issue can occur during only manual flight. The erroneous AOA input can pitch the aircraft’s stabilizer trim down for up to 10 seconds as a time.
The plane maker is expected to caution pilots to use the electric stabilizer trim to reverse the downward stabilizer trim, but the nose-over can begin again five seconds after those switches are released, the official added.
The repeated uncommanded nose down action can be stopped by deactivating the stabilizer trim system, according to the official. Boeing warns that the stabilizer system can reach its full downward position if not counteracted by pilot trimming the aircraft and disconnecting the stabilizer trim system.
The service bulletin is likely to be the prelude to a formal airworthiness directive from the Federal Aviation Administration.
Boeing did not immediately respond to a request for comment.
The bulletin is expected to be issued as early as Wednesday morning, according to Bloomberg News, which
first reportedthe impending operator notification.