This October 2008 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.
Aircraft: Beech Bonanza. Injuries: None. Location: Houston, Texas. Aircraft damage: Substantial.
What reportedly happened: While in cruise flight the propeller’s rpm unexpectedly increased to approximately 2,900. The pilot attempted to reduce the rpms via the propeller governor but it didn’t work so the pilot reduced the engine throttle. Seconds later the engine began to make a knocking noise, then engine power was lost. The pilot performed a forced landing in a rough field. The airplane caught fire.
The post-accident examination of the engine revealed that the oil filter adapter housing had a fracture that allowed the engine oil to escape, resulting in oil starvation and a subsequent engine seizure. The accident flight was the first flight since the airplane’s annual inspection which included the last oil filter change. Due to thermal damage to the oil filter adapter and oil filter, the reason for the fractured oil filter adapter could not be determined.
Probable cause: The total loss of engine power due to a fracture in the oil filter adapter housing.
For more information: NTSB.gov