Helicopter accident during canyon maneuvering

6 fatalities • Mt Steens, United States of America • Flight

A helicopter crashed into rising terrain while attempting to reverse direction inside a gorge, resulting in the deaths of all six people on board.

What happened

During a flight mission, the pilot navigated an aircraft into a canyon, flying at a low altitude that deviated from the intended mission profile. As the pilot proceeded upslope toward rising terrain, an attempt was made to reverse the direction of the flight. During this maneuver, the aircraft entered a stall and subsequently transitioned into a spin. This resulted in an uncontrolled descent and a collision with the ground.

All six occupants on board were killed in the accident. The pilot's background included significant experience in helicopters, but at the time of the event, they had accumulated only approximately 13 hours of flight time specifically in this make/model.

Findings

Several contributing factors were identified following the investigation. The aircraft was operating slightly above its maximum gross weight, and the flight took place under conditions of high density altitude. Investigators determined that the pilot misjudged the necessary clearance and failed to maintain adequate airspeed during the turn. Additionally, the decision to fly at low altitudes within the gorge was deemed improper in-flight planning. Ultimately, the stall/spin maneuver led to the loss of control and the fatal impact with the terrain.

Probable cause

The pilot lost control of the aircraft during a reversing maneuver due to a stall and spin caused by excessive weight, high density altitude, and insufficient airspeed.

Frequently asked questions

What happened in the 1986-08-21 Cessna 207 Skywagon/Stationair accident near Mt Steens, United States of America?

A helicopter crashed into rising terrain while attempting to reverse direction inside a gorge, resulting in the deaths of all six people on board.

Were there any fatalities in the 1986-08-21 Cessna 207 Skywagon/Stationair accident?

The accident was fatal, resulting in 6 fatalities.

What aircraft was involved and where did it happen?

The accident on 1986-08-21 involved a Cessna 207 Skywagon/Stationair, registration N73569, operated by Idaho Helicopters, at Mt Steens, United States of America.

What was the probable cause of the accident?

The pilot lost control of the aircraft during a reversing maneuver due to a stall and spin caused by excessive weight, high density altitude, and insufficient airspeed.

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