Flight and Weight Information
The helicopter departed for a low altitude power line inspection flight. It was approximately 100 pounds above its maximum gross weight at takeoff. The flight lasted about one and a half hours.
GPS Data Analysis
A hand-held GPS receiver recovered near the wreckage contained data from the entire flight. The final 23 seconds of recorded data showed the helicopter initially heading 088 degrees. It then began a left turn to a heading of 285 degrees. During this turn, the ground speed decreased from 30.4 knots to 3.6 knots before the data recording ended.
Impact and Wreckage Examination
The helicopter descended vertically through trees and came to rest on its right side. Examination of the collective control revealed it was in the full-up position. The low rotor RPM warning light filament showed significant stretching and deformation, consistent with a hot impact.
Pilot Information
The pilot held 417 total flight hours, with 370 hours specifically in Robinson R-22 helicopters.
Relevant Safety Information
The Robinson R-22 Pilot Operating Handbook, Safety Notice #SN-10, states that a primary cause of fatal accidents in light helicopters is failure to maintain rotor RPM.