On September 10, 1995, a Cessna P210N (registration N3674P) was involved in an aviation accident near Black Diamond, WA. Investigators recorded the probable cause as: improper maintenance which led to oil starvation due to a inadequately tightened B-nut in an oil line. A factor was the lack of suitable terrain for a forced landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot reported a loss of power while conducting aerial photography near Mt. Rainier and attempted a glide to a suggested airstrip. The engine then failed completely, resulting in a crash into trees near a river. Investigation revealed oil starvation due to a loose B-nut on a turbocharger oil line that had recent maintenance.
Incident Overview
During aerial photography operations over mountainous terrain near Mt. Rainier, the pilot advised Air Traffic Control that the aircraft had experienced a loss of power. The pilot elected to attempt a glide from an altitude above 10,500 feet mean sea level to an airstrip suggested by ATC as a possible forced landing site. During the descent, the engine lost total power. The aircraft subsequently crashed into trees on the north side of a river. A paved road ran along the south shore of the river, and the crash site was within about a mile of an abandoned airstrip.
Investigation Findings
Disassembly and inspection of the engine revealed an internal failure due to oil starvation. A B-nut on an oil line to the turbocharger was found to be loose. Maintenance records indicated that this oil line had been subject to recent maintenance performed by company personnel.