Accident Overview
A helicopter pilot was hover taxiing the helicopter in a confined area after refueling. According to the pilot, there was a large tree to the southwest and a light pole to the northeast of his position. He recalled beginning to taxi to the northwest, away from the light pole, but a significant left quartering wind of about 9 knots gave him difficulty controlling the tail.
Pilot Actions
The pilot reported that he did not feel he could turn the nose into the wind in the confined area and decided to climb vertically to avoid obstacles. As he ascended, he encountered a wind gust, and the tailboom yawed to the right and struck the light pole. The helicopter then descended, impacted the ground, and came to rest on its left side.
Damage
The helicopter sustained substantial damage to the fuselage, the main rotor system, and the tail rotor system.
Mechanical Status
The pilot reported that there were not any mechanical anomalies or malfunctions with any portion of the helicopter that would have prevented normal flight operations.
Weather Information
The nearest weather reporting station was two miles north-northwest. The meteorological aerodrome report around the time of the accident indicated the wind was out of 160 degrees true at 11 knots.
Reference to FAA Helicopter Flying Handbook
FAA-8083-21A, Chapter 11-20, paragraph 2, describes weathercock stability in the region of 120–240 degrees. In this region, the helicopter attempts to weathercock its nose into the relative wind. Unless a resisting pedal input is made, the helicopter may start a slow, uncommanded turn. If the pilot allows a right yaw rate to develop and the tail of the helicopter moves into this region, the yaw rate can accelerate rapidly. The handbook emphasizes the importance of maintaining positive control of the yaw rate and devoting full attention to flying the helicopter to avoid the onset of loss of tail rotor effectiveness (LTE) in downwind conditions.