CHI95LA029

The pilot left the helicopter unattended with the engine at idle and the rotor system disengaged. While unattended, the engine accelerated, and the rotor system drive belts engaged. The unpiloted helicopter moved across the ground, struck a pole and was substantially damaged. Post-crash inspection revealed the collective in the full up position.

On November 2, 1994, at 1515 hours central standard time (CST), a Hughes 269-C helicopter, N9294F, operated as a business aircraft by Henkle Drilling and Supply, Inc., of Garden City, Kansas, contacted a pole with its rotor blades at the owner's facility one mile west of Garden City, Kansas. The helicopter turned on its side and was substantially damaged. There were no persons on board the helicopter during the accident and no injuries. Visual meteorological conditions existed at the time of the accident and no flight plan was filed.

The flight was operating under 14 CFR Part 91 and had originated from the Garden City Regional Airport at approximately 1445 CST. The airline transport rated pilot had repositioned the helicopter and was awaiting a part to transport to a company site in Sublette, Kansas. After landing at 1450 hours CST, the engine was placed at idle (approximately 1400 RPM), the rotor disengaged, and the pilot exited the helicopter. Winds were 10 knots gusting to 20 knots. The rotors engaged with no persons on board, and the helicopter struck a building.

Post-crash inspection revealed that the belt tensioner was still in the disengaged position, and the collective was in the full up position. Witnesses stated that the gusting winds were causing the static rotor blades to flap vertically. As rotor blade pitch is increased, the engine anticipator tends to increase engine speed. Maintenance and operations personnel stated that as engine speed increases, the drive belts are able to grab the drive pulleys. Witnesses described hearing the engine operating at a high speed during the accident.