Originally Posted by
acad_l
Only airliner I can think of that turned out to have a stability issue was the BAC-111. But that was found late in the game, not by design, and the remedy apparently worked.
I am not a pilot nor an engineer, just a geek so correct me if I am wrong but there have been systems similar to MCAS to keep planes stable during hand flying. The ones I know of are the LSAS system on the MD11 and the pilon flaps on the MD90. The difference is that they where not relying on a single sensor.