Incident Overview
During the approach, the first officer (FO) asked the captain whether he wanted to activate the wing deice boots to remove ice. The captain responded, "...it's going to the hangar. I'll run 'em on the ground..." The FO then retarded power over the threshold, causing the sink rate to increase. The captain observed a descent rate of 900 feet per minute. The FO applied additional back pressure on the yoke, but it was insufficient to arrest the high sink rate. Further back pressure was applied, and the stall horn sounded, followed shortly by the captain stating, "I got it."
Damage and Structural Findings
The hard landing resulted in the right main landing gear breaking, the fuel tank rupturing, and the right wing rear spar bending upward. Approximately 18 hours after the accident, investigators observed 3/16 inch of rime ice mixed with clear ice on the leading edges of the wing, horizontal stabilizer, and vertical stabilizer. The ice featured finger-like protrusions oriented vertically to the wing surfaces.
Training and Procedures
The company's line operations manual did not discuss flight characteristics or landing techniques specific to wing ice contamination. Additionally, neither pilot had received the company's current crew resource management (CRM) training at the time of the accident.
Probable Cause
The official findings stated that the probable cause was the first officer's failure to maintain a proper descent rate during the landing, and the captain's inadequate supervision by not taking timely action to ensure a safe landing. Contributing factors included the company's failure to provide adequate training on the airplane's flight characteristics and/or handling techniques under conditions of wing ice contamination, the company's failure to ensure both pilots had received current CRM training, and the existing weather conditions that led to ice accumulation on the airplane's wing.