What happened
On 6 November 2015, the pilot of a Robinson R22 helicopter, registered VH-NCL, prepared to conduct a private flight with one passenger on board, from Newman Airport in Western Australia.
At about 0830 Western Standard Time (WST), the helicopter lifted off to about 10 ft above ground level, and the pilot commenced hover-taxiing. As the helicopter started to move forwards, it encountered a gust of wind from behind and sank rapidly. The helicopter landed heavily, then bounced and rotated rapidly to the right. During the accident sequence, the main rotor blade severed the tail, and the helicopter sustained substantial damage (Figure 1). The pilot and passenger were not injured.
Figure 1: Accident site showing damage to VH-NCL
Source: Airservices Australia - Aviation Rescue Fire Fighting
Loss of tail rotor effectiveness
Loss of tail rotor effectiveness (LTE) causes a yaw to the right in helicopters with a counter-clockwise rotating main rotor. When operating at airspeeds below 30 kt, a tailwind may result in an uncommanded turn, if the tail rotor is unable to provide adequate thrust to maintain directional control. To reduce the onset of LTE, the United States Federal Aviation Administration (FAA) Helicopter Flying Handbook, advises pilots to:
Avoid tailwinds below an airspeed of 30 knots. If loss of translational lift occurs, it results in an increased power demand and additional anti-torque pressures.
To recover from LTE:
If the rotation cannot be stopped and ground contact is imminent, an autorotation may be the best course of action. Maintain full left pedal until the rotation stops, then adjust to maintain heading.
Aviation Short Investigations Bulletin Issue 46
Purpose of safety investigationsThe objective of a safety investigation is to enhance transport safety. This is done through:
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