Bell OH 58A N109PD accident near Omaha, Nebraska

Probable cause

A partial loss of engine power for reasons that could not be determined based on the available evidence.

NTSB analysis

Shortly after takeoff and while climbing through 200 to 250 ft above ground level in a left turn, the pilots of the helicopter noted an audible horn, low main rotor rpm, and a loss of altitude” indicating a loss of rotor RPM and engine power." The flying pilot entered an autorotation to recover rotor rpm, and the pilots located a forced landing location. Upon touchdown, the forward landing gear skids dug into the soft terrain, and the helicopter rocked forward and backward, resulting in the main rotor contacting the tail boom.

An examination of the helicopter revealed no preimpact mechanical anomalies that would have precluded normal operation. The engine was removed and placed in a production test cell for an engine test run. The engine responded normally to all power demands without surging or hesitation. Based on the available evidence, the reason for the partial loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for CEN19LA121 for the full record.