Event Summary
During cruise flight in the vicinity of an airport, the propeller separated from the aircraft. The pilot was provided vectors to the airport and subsequently entered the traffic pattern for landing. The downwind leg was extended due to a strong tailwind. On final approach, a strong headwind caused the aircraft to land short of the runway. During the landing roll, the aircraft collided with two fences.
Examination Findings
Post-accident examination of the aircraft revealed that six propeller mount bolts had failed due to fatigue. The fatigue failure resulted from improper placement of the propeller mounting shim. The correct placement of the shim is between the propeller flange and the starter gear flange. However, the shim had been installed between the engine crankshaft flange and the starter gear flange. The aircraft manual states that propeller mount bolts may fail due to relative movement between the two flanges if the shim is not installed in the proper location.
Maintenance History
Approximately 45 hours before the accident, the aircraft experienced a sudden engine stoppage. That event led to the removal, overhaul, and reinstallation of the propeller. The improper shim placement likely occurred during this maintenance.