Accident Overview
The pilot was flying a 40-year-old airplane to another airport for routine maintenance. Approximately 10 minutes after takeoff, while cruising at 5,000 feet, the pilot reported a cabin heater fire. The flight ended when the airplane collided with trees after maneuvering at low altitude.
Witness Observations
Witnesses observed the airplane circling close to the ground, as if the pilot was searching for a suitable landing area. After several minutes, the airplane made an abrupt left turn and struck trees.
Examination Findings
Post-accident examination revealed that a cabin fire had occurred, centered around the cabin fuel heater (CFH) located beneath the aft passenger seat. The most severe fire damage was concentrated in the vicinity of the heater fuel control unit, which was largely melted away. Investigators found no evidence of a fuel safety valve installed in the supply line to the CFH. Additionally, the use of vibration loops and flexible lines in the fuel system was not evident.