The airline transport pilot reported that the accident flight was the Cessna 441’s first flight after a phase maintenance check, and that he was repositioning the airplane to an airport about 40 nautical miles away.
While en route, the plane experienced a series of avionics and fuel-related anomalies.
He eventually declared an emergency and was cleared to land at the destination airport in Fargo, N.D.
The first approach for landing in instrument meteorological conditions resulted in a missed approach.
About this time, the airframe was accumulating ice and he cycled the deice boots.
During the second approach, the airplane broke out of the clouds, and he proceeded to land.
Before he initiated the landing flare, he reduced engine power to idle, fully extended the flaps, and flared the airplane. He stated the airplane was shaking and shuddering, but no stall warning horn sounded, and then the “bottom fell out.”
The airplane landed hard, and the left engine’s propeller blades struck the runway. The airplane incurred wing spar and propeller damage.
A post-flight examination of the airplane revealed between ½ to 1 inch of rime ice on the leading edge surfaces of both wings, the horizontal stabilizer, and the vertical stabilizer.
The pilot’s operating handbook stated that the deicing boots should be cycled as necessary when ice accumulation reached between ¼ and ½ inch. The amount of ice on the wing and empennage surfaces after the accident was consistent with the pilot not cycling the deice boots as prescribed, which resulted in an excessive ice accumulation on approach and a subsequent aerodynamic stall during the landing flare.
Probable cause: The pilot’s failure to cycle the surface deice boots during the instrument approach in icing conditions, which led to ice accumulation on the leading edges of the wings and empennage, and resulted in an aerodynamic stall and subsequent hard landing.
NTSB Identification: CEN16LA098
This January 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.