Helicopter crash during pinnacle landing demonstration

Casualties unknown • Emmett, ID, US

A helicopter instructor and student pilot were involved in an accident while practicing off-airport landings near a plateau, resulting in a loss of control and a rollover.

What happened

A training flight involving an instructor and a student pilot was underway with the intent to practice off-airport landings. During the flight, the instructor maneuvered the helicopter toward a plateau characterized by cliffs on three sides to demonstrate a pinnacle landing.

As the maneuver was initiated, the instructor observed a change in wind and the development of an excessive sink rate. In an attempt to correct these conditions, the pilot applied collective and throttle. During this correction, the throttle reached its stop, causing the engine RPM to decay.

In response to the decaying RPM, the instructor lowered the collective. The rotorcraft struck the ground with significant force, bouncing approximately 10 to 12 feet into the air before a second impact occurred. During this second strike, the tail rotor made contact with the ground. This resulted in a loss of directional control, causing the aircraft to roll over the edge of the plateau and descend down a steep embankment.

At the time of the accident, the instructor pilot had logged only 3 hours of flight time in this specific aircraft make within the previous 90 days. Weather observations from Caldwell airport, located 11 nm south of the site, indicated winds from 110 degrees at 9 knots with gusts up to 14 knots. The instructor reported that no mechanical malfunctions occurred during the flight.

Probable cause

The pilot's attempt to correct an excessive sink rate and wind change led to reaching the throttle stop and subsequent decay of engine RPM, resulting in a loss of control during a pinnacle landing maneuver.

Frequently asked questions

What happened in the 1998-04-10 Hughes 269A accident near Emmett, ID?

A helicopter instructor and student pilot were involved in an accident while practicing off-airport landings near a plateau, resulting in a loss of control and a rollover.

What aircraft was involved and where did it happen?

The accident on 1998-04-10 involved a Hughes 269A, registration N5161E, operated by Clark, Ron. A, at Emmett, ID.

What was the probable cause of the accident?

The pilot's attempt to correct an excessive sink rate and wind change led to reaching the throttle stop and subsequent decay of engine RPM, resulting in a loss of control during a pinnacle landing maneuver.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X09959. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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