Boeing has completed the fix for the 737 MAX’s MCAS anti-stall system

In a race against the clock to avoid a long standstill of the 737 MAX, Boeing has finished developing a fix for the anti-stall MCAS of this aircraft involved in the fatal Lion Air accident in October.

All 737 MAXs have been grounded for about 11 days after an Ethiopian Airlines accident on March 10th which is similar to that of Lion Air at the end of October.

Boeing was to present the fix to the three American customers (American, Southwest and United) and two non-US carriers (TUI fly Belgium and a non-disclosed airline) and their pilots this Saturday in Renton, Washington State, where the 737 MAX is assembled. The pilots of American Airlines and Southwest had to test the updates to the software Saturday on flight simulators. After the tests, all of them were satisfied they could fly and land the aircraft without incidents.

According to the Wall Street Journal, the US Federal Aviation Agency (FAA), has given a preliminary agreement to the changes (software patch and pilot training) proposed by Boeing. A definitive agreement would only intervene after additional tests and verifications that could take place in the coming weeks.

The FAA had given a deadline no later than April for Boeing to make the necessary changes to this essential system to protect the aircraft, and industrial sources had told AFP that the fix should be ready in ten days.

In addition to the MCAS patch, Boeing has also finished updating the flight and pilot training manuals, as requested by the FAA. Boeing will take care of the training of pilots and is in the process of organising the schedule with the different customers of 737 MAX.

The costs of this training and the invoice for the development of the patch of the MCAS software will be borne by the aircraft manufacturer.

Another important modification of the 737 MAX: Boeing has decided to equip all the aircraft with a warning light signal, a feature that was previously optional and at a cost. Called “disagree light”, this warning signal is triggered in the event of erroneous information transmitted by one or two Angle of Attack (AOA) sensors to the MCAS system. Neither the Lion Air 737 MAX 8 nor that of Ethiopian Airlines were equipped with that optional feature.