Boeing said it made the discovery a year before the two fatal crashes took place but took no action, however, the company insists that this issue would not have endangered flight safety.
The manufacturer said that the aircraft was safe to fly without the feature, an angle-of-attack (AOA) Disagree light, and that pilots could rely on other gauges to show the plane’s speed, altitude, engine performance and other factors, information required for safe flight.
The AOA Disagree alert lets pilots know when two different sensors are reporting conflicting data. Boeing said this feature was meant to be provided as standard, but didn’t realise until deliveries had started, that it was only available if airlines purchased an optional indicator. The company said it planned to resolve the issue later with a software update.
Earlier this year, all 737 Max jets worldwide (387 aircraft) were grounded after an Ethiopian Airlines flight suffered a fatal crash, killing 157 people. Five months prior to that incident, 189 people were killed when a Lion Air plane, also a 737 max, crashed.
According to an FAA spokesman, Boeing had notified the agency in November of a non-working light after the Lion Air crash in October. He said that FAA experts ruled that the non-working indicator presented a low-risk. However, he said a more timely or earlier communication with the airlines by Boeing would have helped reduce or eliminate possible confusion.
At present, it appears that sensors malfunctioned during both accidents, causing the software to push the planes into a nose dive. However, it remains unclear if the warning light in question would have prevented either crash.
This latest revelation has added to concerns over Boeing’s management of the craft’s design and heightened its poor relations with both airlines and customers.
Its failure to disclose this information earlier will add pressure to its scrutiny in multiple federal investigations, which will contribute to the mounting financial costs and the remaining work to get the 737 Max jets back into the air.