The Taiwanese Aviation Safety Council concluded many contributing factors culminated in a stall-induced loss of control of an ATR-72 in February 2015.
TransAsia Airways flight GE235, experienced a loss of control during initial climb and impacted Keelung River, three nautical miles east from its departing runway 10 of Taipei’s Songshan Airport. Forty-three occupants were fatally injured, including three flight crew, one cabin crew, and 39 passengers. The remaining 13 passengers and one cabin crew sustained serious injuries. One passenger received minor injuries. The aircraft was destroyed by impact forces. The aircraft’s left wing tip collided with a taxi on an overpass before the aircraft entered the river. The taxi driver sustained serious injuries and the only taxi passenger sustained minor injuries.
The investigation revealed that during the initial climb after takeoff, an intermittent discontinuity in engine number 2’s auto feather unit (AFU) may have caused the automatic take off power control system (ATPCS) sequence which resulted in the uncommanded autofeather of engine number 2 propellers. Following the uncommanded autofeather of engine number 2 propellers, the flight crew did not perform the documented abnormal and emergency procedures to identify the failure and implement the required corrective actions. This led the pilot flying (PF) to retard power of the operative engine number 1 and shut down it ultimately. The loss of thrust during the initial climb and inappropriate flight control inputs by the PF generated a series of stall warnings, including activation of the stick shaker and pusher. After the engine number 1 was shut down, the loss of power from both engines was not detected and corrected by the crew in time to restart engine number 1. The crew did not respond to the stall warnings in a timely and effective manner. The aircraft stalled and continued descent during the attempted engine restart.
The remaining altitude and time to impact were not enough to successfully restart the engine and recover the aircraft.
Had the crew prioritized their actions to stabilize the aircraft flight path, correctly identify the propulsion system malfunction which was the engine number 2 loss of thrust and then take actions in accordance with procedure of engine number 2 flame out at take off, the occurrence could have been prevented. The investigation report identified a range of contributing and other safety factors relating to the engine’s auto feather unit, crew of the aircraft, TransAsia’s flight operations and management processes, and the regulatory oversight of TransAsia by the Civil Aeronautics Administration (CAA).