Aircraft: Cessna 421. Injuries: 4 Fatal. Location: Sioux Falls, S.D. Aircraft damage: Destroyed.
What reportedly happened: Shortly after the airplane lifted off, the tower controller informed the pilot that a plume of smoke was visible behind the airplane.
Witnesses reported seeing flames at the inboard side of the left engine. The airplane began a left turn. When it reached a southerly heading, the nose dropped abruptly, and the airplane crashed and burned. Witnesses stated that they heard an increase in engine sound before impact.
The post-accident examination determined that the left engine fuel selector and fuel valve were in the OFF position, consistent with the pilot shutting down that engine after takeoff. However, the left engine propeller was not feathered. Extensive damage to the right engine propeller assembly was consistent with that engine producing power at the time of impact. The landing gear and wing flaps were extended at the time of impact.
The post-crash examinations of both engines did not reveal any anomalies consistent with a loss of engine power.
Emergency procedures outlined in the pilot’s operating handbook noted that when securing an engine, the propeller should be feathered. Performance data provided in the POH for single-engine operations were predicated on the propeller of the inoperative engine being feathered, and the wing flaps and landing gear retracted. Thus, the pilot did not follow the emergency procedures outlined in the POH for single-engine operation.
Probable cause: The pilot’s failure to maintain adequate airspeed after shutting down one engine, which resulted in an inadvertent aerodynamic stall and impact with terrain. Contributing to the accident was the pilot’s failure to follow the guidance contained in the pilot’s operating handbook, which advised feathering the propeller of the secured engine and retracting the flaps and landing gear.
NTSB Identification: CEN12FA100
This December 2011 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.