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Casualties unknown

Helicopter crash during aerial application takeoff (N62391)

Winters, CA, US

On May 4, 1988, a Hiller UH-12E (registration N62391) operated by Pingrey Bros. was involved in an aviation accident near Winters, CA. Investigators recorded the probable cause as: The pilot's failure to maintain adequate airspeed and altitude during takeoff from a loading truck, which resulted in a collision with the terrain. 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 2026-06-19Data APIEditorial standards

A helicopter descended into ground effect and collided with terrain while attempting takeoff from a loading truck for an aerial application flight.

What happened

The pilot was conducting his 16th aerial application mission of the day when he attempted to launch the helicopter from a loading truck. Prior to the takeoff attempt, the pilot reduced the chemical load from 90 gallons to 70 gallons because the wind conditions had become variable. As the helicopter lifted off, it descended into ground effect, which is the zone where the aircraft normally begins to attain translational lift. The helicopter subsequently collided with the terrain and was destroyed in a post-impact fire.

The investigation

During the investigation, the pilot stated that he was unable to stop the descent despite applying full power. This suggests that the aircraft lacked sufficient performance to climb out of ground effect under the prevailing conditions.

Probable cause

The pilot's failure to maintain adequate airspeed and altitude during takeoff from a loading truck, which resulted in a collision with the terrain.

Frequently asked questions

What happened in the 4 May 1988 Hiller UH-12E accident near Winters, CA?

A helicopter descended into ground effect and collided with terrain while attempting takeoff from a loading truck for an aerial application flight.

What aircraft was involved and where did it happen?

The accident on 4 May 1988 involved a Hiller UH-12E, registration N62391, operated by Pingrey Bros., at Winters, CA.

What was the probable cause of the accident?

The pilot's failure to maintain adequate airspeed and altitude during takeoff from a loading truck, which resulted in a collision with the terrain.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X25711. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.