The Cessna 170 had not been flown for about eight months.
Before departing to practice landings at the airport in Ridgely, Maryland, the owner added aviation gasoline to the fuel tanks, which also contained automotive gasoline that had been added about six to eight months previously.
While on the downwind leg of the traffic pattern, the plane experienced a sudden total loss of engine power. The pilot was not able to restart the engine or land on the runway, so he performed a forced landing to a field.
During the landing, the airplane hit a ditch and sustained substantial damage to the fuselage.
The plane had been operated for about six hours since its most recent documented annual inspection, which was performed about three years before the accident.
The pilot reported that he found water in the fuel system the day before the accident, but that fuel samples taken before the flight were not contaminated.
Examination of the engine did not reveal evidence of any catastrophic engine malfunction, however at the time of the examination, the engine and wings had been removed from the fuselage, which precluded an examination of the airplane’s fuel system.
The NTSB determined the probable cause as a total loss of engine power for reasons that could not be determined based on the available evidence.
NTSB Identification: ERA14LA050
This October 2013 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.