Robinson Helicopter R22 N7020U accident near Las Vegas, Nevada

Probable cause

The loss of helicopter control as a result of the loss of tail rotor effectiveness.

NTSB analysis

The student pilot was conducting approach and departure practice in the single main rotor helicopter. The practice area was a flood control basin located in the desert about 3 miles east of mountainous terrain. The basin was bounded on its east side by a 1-mile-long concrete levee oriented approximately north-south, which rose about 50 ft above the basin floor. The west-facing wall of the levee was sloped about 25 degrees to the horizontal and was topped by a level road. After an uneventful approach to the road from the north, the pilot slowed to a hover-taxi, and then, without touching down, he added power and control inputs to begin his departure straight ahead. The helicopter began to yaw to the right, and the pilot was unable to correct the rotation. The helicopter drifted west over the sloped part of the levee, continued to rotate while descending, and the pilot then attempted to land. The tail rotor struck the levee, and the helicopter landed hard on the sloped wall, facing uphill.

Postaccident examination of the helicopter and several components did not reveal any deficiencies or failures that would have precluded normal operation. The only definitive wind information was from the pilot's departure airport about 9 miles away from the basin, which reported that the wind was about 6 knots from the east-southeast, and the pilot reported that the wind at the basin was similar. The late-morning timeframe, combined with the local topography and desert environment, led to unpredictable wind and/or gusts at the accident site. The pilot's description of the accident circumstances and events were consistent with a loss of tail rotor effectiveness that occurred as the pilot was attempting the transition from the hover-taxi to the departure segment.

Text from the NTSB. Open the NTSB docket for WPR16LA056 for the full record.