Boeing software developers tied plane sensor malfunction alerts to optional sensor displays. Warnings never activated on the Indonesian and Ethiopian planes without the optional displays. It took two crashes and hundreds of human casualties before Boeing took addressed the issue discovered back in 2017.
In 2017, Boeing unexpectedly discovered that one of the warning indicators in its newest 737 MAX jet was not working. Upon review, the company decided that the issue didn’t warrant immediate action and postponed resolving it until 2020. This finding was contained in a letter by two US Representatives sent to both Boeing and the Federal Aviation Administration (FAA), revealed by a Houston Chronicle report.
The Chronicle reported that Representatives Peter DeFazio of Oregon and Rick Larsen of Washington, are both leaders of the House committee investigating the two MAX crashes that took the lives of several hundred people.
The alarm in question should activate when there is a discrepancy in readings between the two Angle of Attack (AOA) sensors, possibly indicating a malfunction. This was to be a standard feature on all 737 MAX planes.
In 2017, the company realized that the alarm was tied to AOA displays, which display individual sensor readings and are an optional add-on, The New York Times reported on Wednesday. This standard safety feature effectively only worked on planes equipped with the optional add-on.
Upon discovering this safety issue the company should have made it a priority to fix the warning malfunction as fast as possible, but that was not the case. Instead, Boeing performed an internal review and deemed the AOA warning disagreement non-crucial and scheduled a fix for 2020 when a new version the MAX 10 was scheduled to be rolled out.The AOA sensors malfunctioned in both the Indonesian and Ethiopian planes that crashed in October and March, killing a total of 346 people, according to a report by Houston Chronicle.
In their letter, lawmakers point out that Boeing ramped up the schedule for the update only after the planes crashed, resulting in the boycott of 737 MAXs around the world for safety reasons.
Lawmakers asked Boeing why they did not deem the flaw crucial to flight safety and failed to report it to the FAA immediately.
Boeing did disclose the flaw in November 2018, after the first plane crashed. However, the Administration also deemed the flaw to be “low risk” and demanded it be fixed with the next update, the FAA said in a statement, according to the Houston Chronicle.
Testifying before lawmakers last month, FAA Acting Administrator Daniel Elwell said he “wasn’t happy” with the 13-month gap between when the problem was discovered and the agency was informed.