Originally Posted by
cooperplace
yep, I sure as hell don't and I'd love to see it explained in a way so that a dimwit like me (LSA pilot) can understand.
In reference what people are discussing here it's fundamentally straightforward, albeit perhaps not easily explained without a piece of paper - let me see if I can provide a suitable analogy:
If you were to push a small (non power-steer) car somewhere near the middle of its boot (you're in Oz so I don't need to say 'trunk' :-) it would travel in a relatively straight line along a flat road without much input from the driver.
If you then moved that push/thrust off-centre (let's say to the right) and started pushing, the vehicle would want to drift gradually to the left if it weren't corrected by the driver via the steering wheel.
If you pushed harder, and/or you moved to the right-hand extremity of the boot then the vehicle would have a significantly greater left-hand drift which could require considerable correction by the driver, and even catch them unawares.
MCAS on the 73-MAX is a little as if you installed automatic centering power steer to this car so that an off-centre push wouldn't cause it to drift off-line significantly and wouldn't require much, if any, effort/correction by the driver.
To move from the analogy to the reality; as the MAX has significantly more thrust (push) than earlier 73 models, and that thrust is further out (down) from the centre of the aircraft (in elevation) it will want to pitch up significantly when power is applied. This is not a good thing and so without major re-design of the control surfaces or airframe MCAS is a system that takes data from an Angle-Of-Attack (AOA) sensor and corrects for this undesirable pitch up by trimming down, should it 'see' the aircraft deviating from its true path. It does this without specific input from the pilot.
There's clearly somewhat more detail around the actual operation/methodology of MCAS as we understand Boeing's implementation, but I think this gives the essence of it?
FP.