Incident Overview
A helicopter being flown by a student pilot from the left seat, with a certified flight instructor (CFI) who was also the owner, experienced a gradual loss of power while flying over high terrain at approximately 70 mph. The CFI took control and attempted an airstart, which was unsuccessful. The pilot then attempted to arrest the descent, but the aircraft impacted the ground with such force that it broke up on impact.
Damage Details
The impact caused both left and right skids to collapse. The tail boom and rotor were separated at approximately the station 180 point and were found about 25 feet from the main wreckage.
Control Configuration
Dual controls were installed in the helicopter. However, on the right side, there were no torque pedals attached to the torque control stubs.
Engine and Magneto Inspection
Inspection of the aircraft and engine revealed that one magneto was off in its timing and had lost approximately 43% of its magnetism. Both magnetos were found to contain oil and showed carbon brush wear.