EASA satisfied with changes to Boeing 737 MAX: aircraft is safe

In September, EASA conducted a series of test flights in Canada with a 737 MAX prototype. The organization is currently studying the latest documents to be able to publish a draft airworthiness directive in November. This is followed by a further period of four weeks in which public comments can be made on this concept.

The Boeing 737 MAX has been on the ground worldwide since March 2019 after fatal plane crashes with aircraft from Lion Air and Ethiopian Airlines. 346 people were killed. The malfunctioning MCAS system soon turned out to be the culprit. Moreover, pilots did not even know about the existence of this new system.

The MCAS worked on the basis of input from just a so-called angle of attack sensor. In both crashes, the MCAS was triggered by unreliable data from that one sensor. The MCAS repeatedly pushed the nose of the aircraft down, while the pilots tried hard to keep the aircraft in the air.

An important change is that the MCAS will now receive the input from two sensors. In view of an even higher degree of redundancy, EASA wants a third sensor to be added. However, the development of this ‘synthetic sensor’ will take another two years.

This software-based solution will be implemented as standard on the 737 MAX 10, the longest member of the MAX series that Boeing plans to introduce in 2022. The other 737 MAX devices will be retrofitted with this synthetic sensor.

EASA sees no need to keep the devices on the ground for longer. “Our analysis shows that [de boeing 737 MAX] is safe and that the safety level achieved is high enough for us “, says Ky.” We discussed with Boeing that we can achieve even higher safety levels with the third sensor.


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