Boeing knew of 737 MAX glitch a year before crash

WASHINGTON: Boeing engineers identified a fault with a pilot warning system on its 737 MAX aircraft in 2017, a year before the deadly Lion Air crash, the company said.

Boeing said on Sunday that management was unaware of the issue until the crash in Indonesia, which killed 189 people, and the planes were not grounded until after another of the type operated by Ethiopian Airlines went down several months later, leaving a further 157 people dead.

According to Boeing, a supposedly standard piece of equipment that tells pilot about disagreements between angle of attack (AOA) indicators – which measure the plane’s angle vis-a-vis oncoming air to warn of impending stalls – did not activate unless an optional indicator was purchased by airlines.

That left airlines that did not buy the optional indicator – including both Lion Air and Ethiopian Airlines – without the safety feature.

Faulty angle of attack indicator information may have played a role in both of the deadly crashes, causing the 737 MAX anti-stall system to unnecessarily activate and push the nose down toward the ground even as pilots fought to maintain altitude.

“In 2017, within several months after beginning 737 MAX deliveries, engineers at Boeing identified that the 737 MAX display system software did not correctly meet the AOA Disagree alert requirements,” the aircraft manufacturer said in a statement.

A Boeing review “determined that the absence of the AOA Disagree alert did not adversely impact airplane safety or operation”, concluding that “the existing functionality was acceptable until the alert and the indicator could be delinked in the next planned display system software update,” Boeing said. — AP

Engineers at Boeing identified that the 737 MAX display system software did not correctly meet the AOA Disagree alert requirements.

Boeing statement