Helicopter ground impact during low altitude auto-rotation demonstration

Casualties unknown • Hillsboro, OR, US

A flight instructor experienced a helicopter ground impact while demonstrating a low altitude auto-rotation maneuver over soft terrain.

What happened

During a flight instruction session, the instructor began a demonstration of a low altitude auto-rotation. The maneuver was performed while moving forward in a hover at a speed described as a "brisk walk." The intended touchdown location was a grassy area situated slightly east of the runway environment.

Upon touchdown, the helicopter's skids encountered soft terrain, causing them to dig into the ground. This caused the aircraft to rock forward onto the toes of the skids. Immediately following this movement, the main rotor blades made contact with the ground, and the aircraft came to rest on the forward skid toes and the main rotor mast.

The investigation

The instructor reported that there was no mechanical malfunction with the helicopter at the time of the event. The investigation noted that the terrain at the selected site for the auto-rotation was soft.

Probable cause

The helicopter skids dug into soft terrain during touchdown, causing the aircraft to rock forward and the main rotor blades to strike the ground.

Frequently asked questions

What happened in the 2003-10-26 Hughes 269C accident near Hillsboro, OR?

A flight instructor experienced a helicopter ground impact while demonstrating a low altitude auto-rotation maneuver over soft terrain.

What aircraft was involved and where did it happen?

The accident on 2003-10-26 involved a Hughes 269C, registration N7452F, at Hillsboro, OR.

What was the probable cause of the accident?

The helicopter skids dug into soft terrain during touchdown, causing the aircraft to rock forward and the main rotor blades to strike the ground.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20031103X01856. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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