Primary finding
Probable cause
The pilot's failure to remove all water from the fuel tank, which resulted in fuel contamination and a subsequent partial loss of engine power.
Investigator assessment
Analysis narrative
Before the day of the accident, the nose fuel tank cap had been dislodged during a snowstorm, which allowed snow to enter the fuel tank. During preflight inspection, the pilot drained fuel from the fuel tank and discovered water in the fuel. He continued to drain the fuel until no water was visible. The pilot took off and during cruise flight the engine began to run rough so he performed a precautionary landing on a road. He drained fuel from the fuel tank again and once again found water in the fuel. He continued to drain fuel until there was no more sign of water. The pilot’s mechanic responded to the site to assist the pilot. The mechanic drained all of the fuel from the carburetor to ensure there was no water. They started the engine, and it ran normally again so the pilot decided to take off. Shortly after departure from the road, the engine began to run rough again. The pilot landed back on the road. During the landing roll, the right wing impacted a street sign, and the airplane came to rest in a ditch. Postaccident examination of the engine revealed water in fuel samples drained from the gascolator and carburetor. Other than the presence of water, no anomalies were noted with the engine that would have precluded normal operation.
Source record
Factual narrative
On January 13, 2023, about 1530 Alaska daylight time, a Taylorcraft BL-65 airplane, N29886, was substantially damaged when it was involved in an accident near Point Mackenzie, Alaska. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, last month after a heavy snow fall, the nose fuel tank cap was found dislodged, allowing snow to accumulate into the tank. On the day of the accident, during the airplane preflight inspection, the pilot sampled fuel from the fuel tank and found water in the fuel. He drained fuel until there was no more sign of water. He departed from Lake hood Airport (LHD) and during cruise flight the engine began to run rough. He performed a precautionary landing to a road. The pilot drained fuel from the fuel tank again and found water in the fuel. He drained fuel until there was no more sign of water. His mechanic responded to the site to assist the pilot. The mechanic drained all the fuel from the carburetor to ensure there was no water. They started the engine, and it ran smoothly for 10 minutes. The pilot departed from the road to fly back to LHD and shortly after departure the engine began to run rough again. The pilot performed a precautionary landing back on the road. During the landing roll the right wing impacted a street sign, and the airplane came to rest in a ditch. The airplane sustained substantial damage to the right wing. Postaccident examination of the engine revealed water in fuel samples drained from the gascolator and carburetor. Other than the presence of water, no anomalies were noted with the engine that would have precluded normal operation.