Arrow Falcon Exporters Inc OH-58A+ N298CP accident near Myrtle Creek, Oregon

Probable cause

A partial loss of engine power during takeoff for undetermined reasons.

NTSB analysis

The helicopter was equipped with aerial application equipment, however, the chemical tanks were empty at the time of the accident. As the helicopter departed the landing zone, the pilot sensed that more power than usual was being required to clear the 10- to 12-foot trees at the edge of the takeoff zone. He checked the engine instruments, which indicated normal readings, and 100 percent torque. Following his instrument check he heard "popping sounds coming from the engine." The pilot said that once over the trees, between 20 and 30 knots airspeed, the helicopter would not accelerate and settled into the trees despite applying full collective. On scene documentation of the rotor blades indicated leading edge damage and upward bending of the blades, indicative of low rotor energy at the time of rotor blade impact with the trees and terrain. Examination of the engine identified leading edge damage to the compressor blades; however, a functional test cell run of the engine revealed it was capable of producing rated horsepower. No airframe anomalies were identified during the airframe examination that could explain the loss of power.

Text from the NTSB. Open the NTSB docket for WPR09LA471 for the full record.