Casualties unknown

Helicopter crashes during agricultural spraying due to contaminated fuel (N527HA)

Dows, IA, US

On August 21, 1992, a Hiller HILLER UH-12E (registration N527HA) operated by Bonanza Valley Aviation was involved in an aviation accident near Dows, IA. Investigators recorded the probable cause as: The pilot's failure to ensure the fuel was free of contamination, which resulted in engine failure and a subsequent collision with terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 3 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-22Data APIEditorial standards

A helicopter sustained engine failure while conducting aerial application of agricultural chemicals, resulting in a forced landing collision with a ditch caused by fuel contamination.

What happened

The pilot of the accident helicopter reported that an engine failure occurred while he was performing aerial application of agricultural chemicals. The helicopter collided with a ditch during the forced landing.

The investigation

Post accident inspection revealed contaminated fuel in the helicopter fuel system and in the fuel tank used to service the aircraft.

Probable cause

The pilot's failure to ensure the fuel was free of contamination, which resulted in engine failure and a subsequent collision with terrain.

Frequently asked questions

What happened in the 21 Aug 1992 Hiller HILLER UH-12E accident near Dows, IA?

A helicopter sustained engine failure while conducting aerial application of agricultural chemicals, resulting in a forced landing collision with a ditch caused by fuel contamination.

What aircraft was involved and where did it happen?

The accident on 21 Aug 1992 involved a Hiller HILLER UH-12E, registration N527HA, operated by Bonanza Valley Aviation, at Dows, IA.

What was the probable cause of the accident?

The pilot's failure to ensure the fuel was free of contamination, which resulted in engine failure and a subsequent collision with terrain.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X15331. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.