Landing and Engine Cool-Down
A pilot landed a turbine-powered helicopter equipped with high skids at a remote construction site. The site contained several bags of cement that were covered by a plastic tarp and secured with a nylon strap. After landing near the bags, the pilot reduced the engine throttle to flight idle to initiate the mandatory 2-minute engine cool-down procedure.
Vibration and Emergency Shutdown
During the cool-down, the pilot sensed a sudden airframe vibration. In response, he immediately closed the engine throttle and performed an emergency engine shutdown.
Postflight Inspection
A postflight inspection revealed that the plastic tarp had dislodged from the nylon strap and become entangled in the tail rotor hub and blade assembly. As a result of the entanglement, the helicopter sustained substantial damage to the tail rotor drive system and tail boom.
Pilot Statement
The pilot reported that there were no preaccident mechanical problems with the helicopter.