20110131003209A

Aircraft crashed while landing on a pinnacle to drop off personnel to assess site for a new antenna location. Arrived at base of peak of scene of accident and made contact with local law enforcement (pima county sheriffs department, pcsd). Weather and daylight was diminishing, postponed climb to accident site until following day. Following day, personnel from FAA, NTSB MD helicopters and pcsd climbed peak and evaluated wreckage and accident site. Wreckage was located n, NE of watermen peak. Fuselage was located approximately 125' below a pinnacle on an approximately 40 degree slope. Only main rotor blade pieces were located on pinnacle, the remaining wreckage was spread down the slope. One main rotor blade was imbedded in a rock outcropping on edge of pinnacle and slope. Evaluation of wreckage revealed that outside of breaks in airframe and engine controls determined to be caused during accident, flight and engine control continuity was established. In addition, tail rotor and main rotor gearboxes rotated freely. Continuity of main rotor gearbox to engine N2 was verified. Wreckage was then recovered and moved to a secured location. Joined by rolls royce investigator and previous parties, an in-depth examination of the airframe revealed no discrepancies that would indicate an airframe related failure. The tail rotor pedal interconnect tube was fractured between the pilot side and the bellcrank that goes aft to the tail rotor controls. These pieces were evaluated by a metallurgical lab that confirmed all suspect fractures were overload. Engine and related accessories was removed from aircraft and taken to 3rd party engine facility. At facility, the engine outside combustion chamber and right side air tube were changed due to both being dented badly from accident. Following this, engine was placed in the test cell and ran. Engine made rated power and had satisfactory accel check. Passengers interviewed after the accident stated that although aircraft flew through some rain en-route to location, that peak was clear and did not appear to be windy based on vegetation. Witness and/or passengers stated aircraft was landing when aircraft bounced forward or possibly pilot tried to inch aircraft forward. Following this, aircraft began to spin clockwise followed by aircraft impacting ground. Based on available records, aircraft appeared within CG range and was not overweight.3-8-2011VISITED crash site again with MD helicopters representative. Found numerous small fragments of the aircrafts tail rotor blades. These fragments indicate a definite plane that tail rotor was facing when tail rotor blades contacted an unknown object. No evidence of tail rotor failure prior to the strike was evident.