Casualties unknown

1985-07-06: Cessna 170B (N2432D) — Swan Lake, MT

Swan Lake, MT, US

On July 6, 1985, a Cessna 170B (registration N2432D) was involved in an aviation accident near Swan Lake, MT. 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

A pilot reported an estimated 14 gallons of fuel before departure; after 30 minutes of flight, engine power was lost. A forced landing in a mountainous creek bed resulted in the aircraft striking a tree and overturning. Post-crash examination revealed only trace fuel and an unapproved, deteriorated fuel line.

Overview

A pilot reported that prior to departure, there was an estimated 14 gallons of fuel on board. After approximately 30 minutes of flight, the engine lost all power, necessitating a forced landing in a mountainous creek bed.

Sequence of Events

During the landing roll, the aircraft struck a tree and overturned. The pilot stated that he used a stopwatch to track fuel consumption because the fuel gauges were inaccurate.

Post-Accident Examination

Post-crash examination of the aircraft revealed only trace amounts of fuel in the fuel tanks, lines, carburetor bowl, and accelerator pump. No fuel was found in the gascolator. The engine was later test-run and operated satisfactorily.

The fuel line between the firewall and carburetor was identified as a rubber vacuum line, which was an unapproved installation. The line was so deteriorated and brittle that it broke into several pieces while being removed for examination.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X37091. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.