On May 19, 1987, a Hiller UH-12E (registration N4034T) operated by Robert L. Leverton was involved in an aviation accident near Tolleson, AZ. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter landed on a platform atop a chemical tank truck. While loading liquid chemical, the tail dropped and the helicopter fell 12 feet to the ground, where it was destroyed by fire.
Incident Details
A pilot landed a helicopter on a platform mounted on top of a chemical tank truck. The truck was parked on a slight slope, with its left side six inches lower than the right side. After landing, the pilot reduced engine power to idle, and a loader began transferring liquid chemical into the helicopter.
Sequence of Events
As the loading progressed, the helicopter's tail began to drop. The pilot attempted to increase power to resume flight, but before he could do so, the helicopter fell off the platform. The platform was at a height of 12 feet. Upon impact with the ground, the helicopter was destroyed by fire.