On April 15, 2006, a Central Copters LANCAIR IV-P (registration N671) operated by Mark W. Duffy was involved in an aviation accident near Belgrade, MT. Investigators recorded the probable cause as: The quill shaft between the reduction gear box and the power section of the engine decoupled during final approach. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.
During a night visual approach, the quill shaft between the reduction gearbox and engine power section decoupled, causing loss of propeller drive. The aircraft executed a forced landing on rough terrain, followed by a fire that consumed it.
Event Description
While on final approach for a night visual landing, the quill shaft connecting the reduction gearbox to the power section of the engine decoupled. This failure resulted in a loss of drive input to the propeller, leading to a forced landing off the airfield on rough and uneven terrain.
Landing and Post-Crash Sequence
The initial touchdown was successful; however, during the rollout, the aircraft impacted the terrain. After the aircraft came to a stop, a small fire developed near the engine exhaust. The occupants attempted to extinguish the fire but were unsuccessful. The fire eventually consumed the entire aircraft.
Probable cause
The quill shaft between the reduction gear box and the power section of the engine decoupled during final approach.