The solution, then, is twofold: Boeing started by warning airlines that the MAX’s angle of attack sensors had malfunctioned before, that such a failure could lead the MCAS (Maneuvering Characteristics Augmentation System) to push the plane’s nose down, and that pilots could safely defuse the problem by cutting off the trim system and working the plane manually.
After making sure pilots knew about the problem and how to resolve it, Boeing would work on a longterm solution. Essentially, it would rejigger the software governing MCAS so that it wouldn’t be as prone to jumping into action based on one scary sensor reading, instead considering more data. And it would limit how many times it can engage.
Boeing said it would have it done within a few months. Then the Ethiopian Airlines jet crashed. We don’t yet know if the jet’s MCAS system is what brought the plane down, or what other factors may have been at work. We do know that what seemed a straightforward fix to an unforeseen problem is now muddied—and that the 737 MAX won’t take off again until it’s been cleared up.
Maneuvering Characteristics Augmentation System sounds like a software hack…