Accident Summary
During a familiarization flight, a commercial pilot was entering the airport traffic pattern for landing. He reported turning on the carburetor heat and switching the fuel tank selector to the right fuel tank. Shortly after these actions, the engine experienced a total loss of power. The pilot attempted numerous times to restart the engine but was unsuccessful. Realizing he would not be able to reach the runway, he chose to perform a forced landing in a small field. During the landing approach, the airplane contacted a power line, nosed over, and came to rest inverted. The event resulted in substantial damage to the wings and fuselage.
Postaccident Examination
Following the accident, an examination of the airplane revealed about 16 ounces of water were removed from the fuel system. Water was present in the lower gascolator, the fine fuel filter (upper gascolator), and the subsequent fuel line leading to the carburetor inlet. A brass screen at the carburetor inlet and two carburetor fuel bowl thumb screens contained corrosion, water, and rust. The fine fuel filter was noted to be not easily accessible and could not be drained during a preflight inspection.
Maintenance History
The approved aircraft inspection checklist required washing the carburetor and main fuel filter every 50 hours, and cleaning or replacing the fine fuel filter every 100 hours. The mechanic who completed the most recent inspection stated that he did not drain or check the fine fuel filter. The last logbook entry that specifically indicated the fuel filters were cleaned was approximately four years before the accident.
Probable Cause
The probable cause of the accident was determined to be the mechanic's failure to inspect the fine fuel filter gascolator as required during the most recent inspection, which resulted in a total loss of engine power due to fuel contamination.