Originally Posted by
DanielW
MCAS (Maneuvering Characteristics Augmentation System), seemingly at the root of these two crashes, was necessary because the plane was inherently unbalanced when they put larger, more modern engines on a 50+ year old airframe design.
I think its a valid point to question whether it would have been better to just design an entirely new plane.
The implementation of MCAS has nothing to do with inherent instability- the M8 has almost the same static margin as the 73H which clearly has no stability issues. If a fault in an AoA sensor causes MCAS to command a nose-down stab trim the runaway trim procedure is followed. Oddly the FAA advisory applies to the M8, while the NG series as a whole also has a stall protection feature integrated into the FCC that will trim the aircraft down in a stall. Too much is being made of "hidden" systems, when the manifesting result falls directly under a procedure that has been in place for decades. If pilots fail to do so, as seems apparent from the data in the Lion Air crash, they fight a progressively losing battle against the stabilizer with the elevators that can only end one way.
With zero data on the ETH crash it's pure speculation, but it's definitely acceptable to consider if there is an AoA sensor/system problem on the M8 but it's not an issue that should lead to hull losses (as evidenced by the Lion Air crews that flew the ill fated jet previously).
The original 737 design's age is irrelevant considering the lack of similarities between that air-frame and those flying today. It's competitor is almost 40 years old and similarly will be flying for decades into the future with new configurations, systems, etc.