20150803016289A

08/03/2015 1600 Local time.

Pilot stated that during approach to a landing spot from the southeast, with winds light and variable from the northwest, at about 300 feet AGL and ½ mile out of the intended landing point, after he cleared a 100 ft. tall tree, he felt flight controls difficult to move indicating to him a hydraulic failure. The helicopter had heavy collective, so any time it was released it would drift downward letting him lose altitude. While he unsuccessfully intended to move the hydraulic switch to the ?off? Position he lost control of the helicopter. At about 30-50 ft. AGL he regained control of the helicopter. He stated that during the late stages of the approach the flight controls were getting increasingly more difficult to move. He was able to shut off the engine but unable to move the collective at all. The cyclic was virtually locked in position and he could not move it at all. While he was reducing approach speed the left spray boom hit weeds and small vegetation about 5 ft. above ground which caused 10-20 degrees yaw to the left. Then the right side dropped slightly. There was a 12-15 inch tall mound of dirt not visible to him because of the vegetation. He stated that the heel on the left skid contacted something which caused the helicopter to have a very tail high slight tilt to the right attitude. During ground contact and the unusual attitude, the main rotor blades struck the tail boom causing the helicopter to roll to the left and come to rest on its left side. He was able to exit the aircraft through the broken windscreen just as the helicopter erupted into flames. There was fuel spilling from the right tank splashing onto the engine. The flight was started with 40-42 gallons of fuel on board and had flown for 35 minutes, so there was approximately 30 gallons of fuel remaining. The helicopter was destroyed and consumed by post-accident fire. Verbal counseling was completed on 08/26/2015.