Boeing Knew of 737 Max Warning Light Issue for 3 Years, Lawmakers Say

Boeing 737 cockpit

Boeing discovered an issue with a critical cockpit warning light in the beleaguered 737 Max aircraft in 2017, two congressmen said on Friday, but only accelerated the timeline to repair it after the first of two deadly crashes.

The AoA or angle-of-attack warning light alerts pilots when two sensors that measure the angle between the airflow and the wing disagree. Faulty data is considered a likely cause of both the Lion Air ad Ethiopian crashes.

In a letter to Boeing and the Federal Aviation Administration, Representatives Peter DeFazio and Rick Larsen, who chair the House Committee on Transportation and Infrastructure and the Aviation Subcommittee respectively, said they had obtained information that suggests that Boeing had known of the AOA alert issue when it began 737 Max deliveries in2017 but had decided to wait until 2020 to address it.

Boeing said in April that a company review found that the absence of the alert did not adversely impact aircraft safety or operation.

“Based on the safety review, the update was scheduled for the MAX 10 rollout in 2020,” the aircraft manufacturer said at the time. “We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again.”

When the 737 Max, which has been grounded for three months, returns to service the safety alert will be a standard feature on all aircraft.  Prior to the Lion Air crash, the alert was part of an optional feature set that relatively few airlines opted for.

Although Boeing has said that a software update that addresses all known issues is complete, it has not yet announced a firm timeline for the planes’ return to the skies.

(Photo: Accura Media Group)