Accident Details
A pilot took off with an 800-pound sling load and used 100% torque to expedite clearing power lines. After clearing the lines, the pilot started a climbing turn and reduced torque to about 80%. At approximately 300 feet above ground level and 50 to 60 knots, the engine began surging, causing the helicopter to yaw repeatedly. Subsequently, the engine lost power. The pilot released the load and made a forced landing in a wooded area, using the collective to extend the flight to an open area. The pilot reached the intended touchdown spot but "ran out of pitch and made a hard landing." The helicopter rolled to the right, and the main rotor blades struck the ground.
Investigation Findings
Examination of the helicopter and engine revealed no reason for the loss of power. The density altitude at the crash site was computed to be 11,093 feet. The helicopter was equipped with an Allison 250-C30P engine, which had recently been installed under STC SH296NM. The flight manual warned that with this engine installed, both fuel boost pumps should be on during engine operation. The engine operated normally during a functional check.