Originally Posted by
gums
Salute!
TNX for the update, Old...
I am more of a pilot and engineer than corporate type. So I wonder why Boeing doesn't bite the bullet and solve the basic aero problem and get rid of MCAS. Otherwise, get the variance from FAA and implement a hybrid FBW system to corrwct the aero problem.
Good grief, Airbus has been flying planes since the early 1990's with zero control stick feedback from AoA or atual aero forces on the elevator, aileron etc.. I really need an explanation of how they got their 320 and following planes certified.
Gums ponders....
That's easy - Airbus is entirely based on the same sort of software covering for aerodynamic quirks that MCAS was intended for, but since Airbus cut all the connections they were forced to use a far more expensive redundant system, allowing certification. Why this was not done in the 737 was to maintain commonality because that's what customers demanded. The reason Airbus did it was so they could provide similar feel to a wide range of planes that actually don't perform similarly which is what their customers wanted.
I expect there is no aero fix besides selling 787s into that slot which, again, the customers buying 737s did not want. I expect that fixed surfaces capable of producing and offsetting nose-down moment at high AoA will overcorrect everywhere else, producing a pronounced nose-down moment in level flight, requiring up-trim and excessive fuel burn.
There isn't a fundamental problem with MCAS; there is a fundamental problem with the AoA system that tells pilots and other systems incorrect information about the status of the airplane. Had the FCCs simply dropped out when the AoA became unreliable, it would have taken MCAS with them. There was no need to report a stall condition when there wasn't one and no need to correct for a high AoA when that was also untrue.