Primary finding
Probable cause
The partial loss of engine power for reasons that could not be determined due to impact and fire damage.
Investigator assessment
Analysis narrative
The airplane was departing the local airstrip to perform an aerial application. About 50 feet above ground level, the pilot noticed a partial loss of engine power and felt a vibration from the engine. The pilot performed a forced landing in a wheat field, and a postimpact fire ensued, which consumed the airplane. Based on his observations during the engine failure, the pilot suspected a cylinder or magneto failure. However, the engine was not disassembled for further examination and the cause of the partial loss of engine power was not determined.
Source record
Factual narrative
On June 7, 2012, approximately 1315 central daylight time, a Grumman G-164B agricultural airplane, N779EF, sustained substantial damage during a forced landing following a partial loss of engine power near Higginson, Arkansas. The commercial pilot, who was the sole occupant, was not injured. The airplane was registered to and operated by J.P. Freppon Flying Service, LLC, of Bald Knob, Arkansas, under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual flight rules (VFR) conditions prevailed for the flight, which did not operate on a VFR flight plan. The local flight was originating at the time of the accident.According to the pilot, he was departing the local airstrip to perform an aerial application when the accident occurred. Approximately 50 feet above ground level (agl), the pilot noticed a partial loss of engine power and felt a vibration from the engine. The pilot attempted to dump the load of fertilizer and performed a forced landing to a field. The airplane came to rest upright in a wheat field and a postimpact fire ensued. The fire consumed the airplane. Post accident examination of the airplane by a Federal Aviation Administration inspector revealed a small crack in the number five cylinder on the Pratt & Whitney R-1340 engine. The engine was not disassembled for further examination, and it could not be determined if the crack was a result of the impact. The pilot thought that a magneto may have failed; however, due to the fire damage, the magnetos and accessories could not be tested. The reason for the partial loss of engine power was not determined.