ROBINSON HELICOPTER R22 BETA near Prescott, AZ — 2011-06-18

Probable cause

The pilot's inadequate compensation for the wind conditions and failure to maintain directional control of the helicopter during taxi, resulting in a loss of tail rotor effectiveness and a subsequent hard landing.

NTSB narrative

The instructor reported that his student was taxiing the helicopter in a north direction along a taxiway parallel to the runway with a near direct tailwind of 10 knots with gusts to 19. The student started to lose tail rotor authority over the helicopter. At this time the instructor took control of the helicopter and proceeded to apply full left pedal until he regained tail rotor authority and directional control. Because of the strong wind from the south, the instructor opted to keep control of the helicopter until they were airborne and he proceeded to continue their taxi to the displaced threshold of the runway. Upon reaching the displaced threshold, the instructor started a 220 degree turn to the left in order to line up with a takeoff direction to the south into the wind. The instructor reported that half way through the turn the helicopter violently yawed to the left, and he applied full right pedal to cancel the yaw but was unable to arrest the helicopter's left yawing moment. The helicopter landed hard on the skids, damaging the main rotor and severing the tail boom aft of the tail rotor blades hazard guard and before the tail rotor transmission. The pilot reported no mechanical issues with the helicopter prior to the flight. The wind limitation listed in the Pilot's Operating Handbook for the helicopter is 25 knots including any gust factor.

Analysis

Primary failure mode

Loss of control

First missed decision gate

Instructor could have aborted the taxi due to wind conditions.

NTSB coding

• Loss of tail rotor effectiveness · Taxi-into takeoff position

Evidence available

• Photos
• 4 docket documents

Docket documents4

• Pilot Operator Report, NTSB Form 6120.1/2form
• Pilot Statementinterview
• Wtness Statementinterview
• Photo 1. Helicopter on runwayphotos