Originally Posted by
gearlever
"According to first analysis of the flight data recorders both propellers of the aircraft went into the feather position."
AvHerald 02/06/2023
Spurious auto-feather happened before:
Spurious auto-feather on TransAsia Airways ATR 72-600
And that is, indeed, what happened, according to the formal investigation conducted by the Aviation Safety Council of Taiwan (ASC). However, the instigating factor likely came as a surprise to most aviation safety specialists due to its rarity: The ASC found that the accident was prompted by a spurious activation of the propeller autofeather system.
Moreover, the council’s final report indicated that even before the accident occurred the morning of Feb. 4, 2015, there was evidence that the system could fail. It had happened twice (without further mishap) due to intermittent signal discontinuities related to aging of the system, and the engine manufacturer had issued service instructions to address the problem.
The ASC found that the airline, TransAsia Airways, had not adequately informed its flight crews of the problem and had not issued clear instructions that a takeoff must be rejected if there are any signs that the autofeather system is not working properly.