[mgsouth]

See edit 2, citing regulation which must be met by all transport aircraft. I think also §25.255 Out-of-trim characteristics, (b) (1) The stick force vs. g curve must have a positive slope at any speed up to and including VFC/MFC

[nobodyandproud]

I don’t see how the FAAs assessment that the 737 MAX was easier to put into a stall for greater that 12 degrees AoA is the same as a “reversal of controls” or a “sudden or excessive reduction of elevator control” stipulated in 25.253

What am I missing?

I am not an aviation expert in any sense.

[mgsouth]

"Reversal of control force", not "reversal of controls". There's also section 25.175, which stipulates "The stick force curve must have a stable slope at speeds"... and gives speed ranges for climb, cruise, approach, and landing. For example:

§25.175 Demonstration of static longitudinal stability.

Static longitudinal stability must be shown as follows:

(a) Climb. The stick force curve must have a stable slope at speeds between 85 and 115 percent of the speed at which the airplane—

(1) Is trimmed, with—

(i) Wing flaps retracted;

(ii) Landing gear retracted;

(iii) Maximum takeoff weight; and

(iv) 75 percent of maximum continuous power for reciprocating engines or the maximum power or thrust selected by the applicant as an operating limitation for use during climb for turbine engines; and

(2) Is trimmed at the speed for best rate-of-climb except that the speed need not be less than 1.3 VSR

These are transports, not fighters. The basic idea is that you want it to be harder work to make a sharper maneuver, and want the aircraft to naturally level out. If the force required decreases for a steeper pitch/roll/yaw, then the plane will naturally want to intensify the maneuver. It's like a car with oversteer--let go of the steering wheel and it will make a sharper turn. As the article cited said, the FAA and Boeing's test pilots weren't happy with the yoke forces in certain situations.

[nobodyandproud]

Thanks for clearing that up.

Now is it unusual for sensors and computer controls to help meet the airworthiness requirements?

I’m guessing it’s definitely not preferable.

I also think everyone is agreed that Boeing (the company and decision makers) really fucked up here, but it seems like a chain of bad decisions at every stage has played a part in this disaster.

[mgsouth]

There's all kinds of these artificial enhancements in aircraft. They range from "stick shakers" [0] (which cause the control stick/yoke to shake when the plane detects a near-stall) to yaw dampers (which counteract "Dutch Roll" in swept-wing planes) [1] to full-blown "you tell me what you want and I'll keep the plane from tumbling out of the sky" control systems for fighters [2]. There are also "flight envelope protection" systems which prevent pilots from overstressing aircraft. What's uncommon is for them to lack redundancy. Yeah, Boeing has much bigger problems than just MCAS.

[0] https://en.wikipedia.org/wiki/Stick_shaker

[1] https://aviation.stackexchange.com/questions/6391/what-is-th...

[2] https://en.wikipedia.org/wiki/Lockheed_F-117_Nighthawk#cite_...