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Casualties unknown

Helicopter Hard Landing Following Loss of Main Rotor RPM During Training Maneuver (N1348Z)

Porterville, CA, US

On September 6, 1995, a Hiller UH-12C (registration N1348Z) was involved in an aviation accident near Porterville, CA. Investigators recorded the probable cause as: the flight instructor's inadequate supervision of the flight; the dual student's improper use of the flight controls; and improper remedial action. 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 2026-07-04Data APIEditorial standards

A dual student inadvertently applied aft cyclic, then raised the collective abruptly, causing the helicopter to climb and lose main rotor RPM. The CFI's autorotation resulted in a hard landing.

Incident Sequence

During a training flight, a dual student attempted to bring the helicopter to a hover. The student inadvertently applied aft cyclic input, causing the helicopter to begin moving rearward. To correct this, the student abruptly raised the collective. The helicopter climbed to approximately 18 feet above ground level, and the main rotor RPM began to decay.

The certified flight instructor (CFI) assumed control of the helicopter and lowered the collective in an effort to regain main rotor RPM, but was unsuccessful. The CFI then performed an autorotation. Due to the decaying main rotor RPM, the helicopter sustained a hard landing during the autorotation.

Findings

The helicopter did not experience any preimpact malfunctions or failures.

Frequently asked questions

What happened in the 6 Sept 1995 Hiller UH-12C accident near Porterville, CA?

A dual student inadvertently applied aft cyclic, then raised the collective abruptly, causing the helicopter to climb and lose main rotor RPM. The CFI's autorotation resulted in a hard landing.

What aircraft was involved and where did it happen?

The accident on 6 Sept 1995 involved a Hiller UH-12C, registration N1348Z, at Porterville, CA.

What was the probable cause of the accident?

the flight instructor's inadequate supervision of the flight; the dual student's improper use of the flight controls; and improper remedial action.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001207X04521. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.