Primary finding
Probable cause
A ruptured oil line, which resulted in oil exhaustion and subsequent loss of engine power.
Investigator assessment
Analysis narrative
The pilot said that as he was departing north from the airport, he 'noticed a puff of smoke.' He headed back to the airport. While en route to the airport, the engine began to run rough, then quit. The pilot elected to force land the airplane on a road. When he determined that he would not reach the road, he turned to land the airplane in an adjacent field. On approach to the field, the airplane struck an electrical wire. The airplane subsequently impacted on the field and came to a stop. Examination of the wreckage revealed that an oil line running from oil cooler to the engine case had ruptured near the back of the engine.
Source record
Factual narrative
On March 31, 1996, at 1558 central standard time (cst), a Piper, PA-28-140, N5932U, operated by a private pilot, sustained substantial damage when during a forced landing, the airplane struck an electrical wire. The airplane subsequently impacted the terrain. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under 14 CFR Part 91. No flight plan was on file. The pilot reported no injuries. The local flight originated at Thief River Falls, Minnesota, at 1545 cst. In his written statement, the pilot said that as he was departing north from the airport, he "noticed a puff of smoke." He headed back to the airport. While en route to the airport, the engine began to run rough, then quit. The pilot elected to force land the airplane on a road. When he determined that he would not make the road, he turned so he could land the airplane in an adjacent field. On approach to the field, the airplane struck an electrical wire. The airplane subsequently impacted on the field and came to a stop. The Federal Aviation Administration (FAA) inspector who examined the wreckage at the scene found the airplane resting upright in a snow-covered field. The airplane's forward fuselage, from the cowling aft to the crew compartment was bent. The airplane's nose wheel and firewall were bent up and aft into the underside of the engine cowling. The propeller exhibited bending. Both main landing gear were sheared off. Flight control continuity was confirmed. Fuel was noted in both wing tanks, and the smell of fuel was evident at the scene. No oil was found on the engine dipstick. The examination of all other airplane systems revealed no anomalies. The engine was removed and examined at AIC Maintenance, Inc., Castleton, North Dakota, on April 17, 1996. The examination revealed that the oil line running from oil cooler to the engine case had ruptured near the back of the engine. -