Reply to post: Re: MCAS is being misportrayed

Boeing big cheese repeats pledge of 737 Max software updates following fatal crashes

steelpillow Silver badge
Boffin

Re: MCAS is being misportrayed

The root of the problem is that the lifting engine cowlings moved the aerodynamic centre forward of the centre of mass at high AOA. The traditional solution is to move the aircraft centre of mass forwards likewise, for example by extending the forward fuselage. This of course would mean a major structural redesign and could have further ramifications, such as a taller tailfin.

Another approach that has been used successfully is to introduce a "lifting tail". This is a tailplane or horizontal stabilizer optimised to provide a little lift in normal flight. It acts to move the aerodynamic centre back aft of the existing centre of mass. But that would reduce fuel economy and range, and might also require a larger tailplane and strengthened rear fuselage.

The modern approach is to fix such handling problems in the software so that, even if the plane flies like a brick tied to a pig, it still feels like a Spitfire. This was, very sensibly, the MCAS solution. Except, it doesn't feel like a Spitfire, it feels like a pig that has eaten the brick. Worse, Boeing and the FAA together chose not to train pilots in the gentle art of turning it off. And that is down to bad engineering, bad certification, and bad operational support.

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