Change Reported for 737 MAX Flight-Control Software

Aug. 4, 2019
The revision stems from an error discovered in testing of an earlier reprogramming effort – resulting from malfunction cited as the cause of two fatal crashes

The Boeing Co is changing the planned revision to its 737 MAX flight-control software to fix an error discovered by the Federal Aviation Administration and reported in June, following testing of an earlier software revision. Neither Boeing nor FAA has confirmed the change, which has been reported citing company sources.

Boeing is working to the programming error cited as the cause of two fatal crashes of the 737 MAX. The twin-engine jet has been idled worldwide following the crashes of an Ethiopian Airlines flight in March and an October 2018 crash for Indonesia’s Lion Air. Boeing halted assembly and delivery on the aircraft series (for which it has an order backlog of more than 4,600 aircraft), and the Federal Aviation Administration, European Air Safety Administration, and other civil aviation regulators, as well as commercial airlines, have suspended the aircraft from service.

A total of 346 passengers and crew members were killed in the two incidents, which Boeing has indicated were caused by a Maneuvering Characteristics Augmentation System (MCAS), also known as "anti-stall" software, developed to off-set a side-effect of the more fuel-efficient engines adopted for the new version of the 737: because of the engines’ larger size, the planes’ aerodynamic behavior is altered, and the MCAS is meant to counteract a stalling tendency.

The software redesign reportedly will incorporate data from two flight-control computers rather than one.

Boeing maintains it plans for the software redesign to be completed and submitted to FAA for approval in September. That would be followed by testing, and if the new program is approved all idled aircraft would be refitted with the updated software.

American Airlines and United Airlines have removed the 737 MAX from their flight schedules through October, though Southwest Airlines and Air Canada canceled all 737 MAX flights until January.