On March 18, 1991, a Mooney M20D (registration N1921Y) operated by Marlyn R. Taylor was involved in an aviation accident near Herlong, CA. Investigators recorded the probable cause as: The separation of a propeller blade due to a fatigue crack originating from a corrosion area on the camber side of the blade. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A propeller blade separated during cruise flight at 7500 feet. The pilot secured the engine and landed safely on a road. Investigation revealed a fatigue crack from corrosion.
What happened
The aircraft was operating in cruise flight conditions at an altitude of 7500 feet mean sea level (MSL). After approximately two and a half hours of uninterrupted flight, a blade detached from the fixed pitch propeller. The pilot immediately secured the engine to stop the rotation of the propeller and executed a landing on a nearby road without further incident.
The investigation
A post-accident analysis of the failed propeller revealed that a fatigue crack had emanated from a corrosion area located on the camber side of the blade. This structural failure was identified as the primary cause of the blade separation.
Probable cause
The separation of a propeller blade due to a fatigue crack originating from a corrosion area on the camber side of the blade.