No fatalities

Helicopter Substantial Damage After Inflight Engine Fire During Pipeline Patrol (N8662F)

Cheyenne, WY, US

On August 6, 1985, a Hughes 369D (registration N8662F) was involved in an aviation accident near Cheyenne, WY. No fatalities were reported. Investigators recorded the probable cause as: An inflight engine compartment fire that led to an unsuccessful autorotation and substantial damage to the helicopter. 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 2026-06-22Data APIEditorial standards
Aircraft registered N8662F
Aircraft registered N8662F. Photo: Alan Wilson from Stilton, Peterborough, Cambs, UK / CC BY-SA 2.0, via Wikimedia Commons

A helicopter suffered substantial damage after an unsuccessful autorotation caused by an engine compartment fire during a pipeline patrol flight. No injuries were reported.

What happened

The flight was conducted as a pipeline patrol operation. While airborne, smoke was observed entering the cabin from the engine compartment. The pilot attempted an autorotation to land safely but was unable to complete it successfully. This resulted in substantial damage to the helicopter.

The investigation

Post-accident examination revealed that the smoke originated from a fire within the engine compartment during flight.

Findings

The primary factor leading to the accident was an inflight engine compartment fire, which necessitated an emergency landing attempt. The pilot's subsequent autorotation was unsuccessful, causing substantial damage to the aircraft.

Probable cause

An inflight engine compartment fire that led to an unsuccessful autorotation and substantial damage to the helicopter.

Frequently asked questions

What happened in the 6 Aug 1985 Hughes 369D accident near Cheyenne, WY?

A helicopter suffered substantial damage after an unsuccessful autorotation caused by an engine compartment fire during a pipeline patrol flight. No injuries were reported.

Were there any fatalities in the 6 Aug 1985 Hughes 369D accident?

No fatalities were recorded in this accident.

What aircraft was involved and where did it happen?

The accident on 6 Aug 1985 involved a Hughes 369D, registration N8662F, at Cheyenne, WY.

What was the probable cause of the accident?

An inflight engine compartment fire that led to an unsuccessful autorotation and substantial damage to the helicopter.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X37445. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.