On August 16, 1989, a Hiller UH-12E (registration N7086) operated by Moseley Aviation, Inc. was involved in an aviation accident near Tolleson, AZ. Investigators recorded the probable cause as: AN ENGINE FAILURE DUE TO WATER CONTAMINATION IN THE FUEL SUPPLY WHICH PRECEDED AN AUTOROTATION AND COLLISION WITH THE GROUND DURING NIGHT TIME CONDITIONS. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A spray helicopter experienced an engine failure after takeoff from a refueling stop. The aircraft autorotated into a field, bounced, and rolled onto its side. A fuel sample taken the same day showed approximately 15% water content.
Accident Sequence
The pilot of a spray helicopter was conducting a takeoff from a refueling stop when the engine failed. The pilot initiated an autorotation, and the aircraft descended into an open field. Upon touchdown, the helicopter bounced and then rolled over onto its side.
Post-Accident Investigation
On the same day as the accident, a fuel sample was taken from the helicopter. Analysis of the sample revealed that approximately 15% of the fuel was water. A subsequent test of the fuel conducted by the company indicated that the contamination level was two quarts to five gallons of fuel. The pilot reported that there were no mechanical problems with the aircraft prior to the accident.
Pilot Statement
The pilot did not report any mechanical issues with the helicopter before the engine failure.