Casualties unknown

1985-06-30: Piper PA-12 (N3081M) — Chugiak, AK

Chugiak, AK, US

On June 30, 1985, a Piper PA-12 (registration N3081M) was involved in an aviation accident near Chugiak, AK. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

An aircraft crashed in a wooded residential area after losing power on takeoff. Investigation revealed use of automotive fuel, degraded by high temperatures, and a carburetor float that had absorbed fuel and sunk.

Accident Summary

An aircraft crashed in a wooded residential area after experiencing a loss of engine power during takeoff. The accident sequence began shortly after departure, when the engine failed to maintain thrust. The aircraft subsequently descended and impacted terrain in a residential zone characterized by wooded surroundings.

Investigation Findings

Post-accident examination of the airframe and powerplant was conducted. Inspection disclosed that automotive-grade fuel had been used in the aircraft, contrary to typical aviation fuel specifications. Laboratory analysis of the fuel sample indicated that it had been subjected to high temperatures, which caused evaporation of approximately 50 percent of the fuel volume. The remaining substance consisted primarily of fuel additives, with the volatile components largely removed.

Carburetor Examination

Further inspection focused on the carburetor, which was found to be equipped with a molded cellular fibre float. Laboratory tests on this float component demonstrated that it was capable of absorbing fuel and had apparently done so during operation. As a result of the fuel absorption, the float lost buoyancy and sank within the carburetor bowl. This condition likely impaired proper fuel metering and contributed to the power loss, though the investigation did not explicitly establish a causal chain.

The findings highlight the presence of degraded automotive fuel and a malfunctioning carburetor float, both of which were identified during the post-accident analysis.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X36632. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.