The Avions de Transport Régional ATR 42-300 was descending to land at Naujaat, Nunavut, Canada, when the flight crew observed indications of abnormally low propeller rpm on the left engine. After touching down, they lost directional control, and the airplane veered off the runway.
Locked Up
The TSB blamed an ATR 42’s runway excursion in part on a contaminant inside a propeller high-pressure pump that led to a condition called pitch-lock.