On 11 February 2015, the pilot of a Robinson R22 helicopter, registered VH-APP, departed from a campsite north of Kalbarri, Western Australia, with a passenger on board. The purpose of the flight was to conduct a reconnaissance of an area where goats were to be mustered that day. Following the reconnaissance, the pilot landed at another site where the passenger disembarked.

When they landed, the passenger disembarked the helicopter under the supervision of the pilot, but the pilot still had some important points that he needed to clarify with the passenger. Rather than shut down the engine, the pilot elected to leave the helicopter running, and after applying cyclic and collective control friction, he disembarked the helicopter to follow the passenger. Just as the pilot and passenger concluded their conversation some distance from the helicopter, the pilot heard the engine RPM increase and noticed that the helicopter was lifting clear of the ground.

The helicopter climbed to a height of about 3 to 4 m above the ground and yawed through about 80 degrees to the left. The helicopter travelled backwards for a distance of about 8 m, remaining laterally level, and sank back to the ground with a significantly nose-high attitude. The tail of the helicopter struck the ground first, followed by the rear end of the skids. Although the helicopter remained upright, it was substantially damaged. The pilot and passenger were both uninjured.

The pilot believed that despite the application of control frictions, the vibration of the helicopter over the following couple of minutes was enough to allow the collective to vibrate up with a commensurate application of engine power.

Leaving any vehicle with the engine running with nobody at the controls carries considerable risk. Pilots are encouraged to exercise extreme caution when considering the circumstances, and not allow perceived time pressure or other external factors to affect their judgement. The company Operations Manual allowed pilots to leave a helicopter unattended with the engine running under specific conditions, but the Robinson R22 Pilot’s Operating Handbook cautions pilots to the contrary.

Aviation Short Investigations Bulletin - Issue 42

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