Overview
A training flight involving a simulated autorotation ended with the helicopter impacting terrain. The incident occurred while the operator's pilot was conducting training under the supervision of the operator's flight instructor.
Sequence of Events
During the training session, the pilot performed a simulated autorotation. While recovering from the autorotation maneuver, the helicopter experienced a total loss of engine power, leading to the impact with terrain.
Maintenance and Procedural Issues
The helicopter's aircraft checklist specifies that engine idle speed should be checked after the last flight each day and prior to engine shutdown, with an acceptable range of 1,400 to 1,600 rpm. However, the operator was not performing these checks. Following the incident, inspection of the engine idle speed revealed it to be between 700 and 800 rpm, well below the prescribed range.
Findings
The investigation documented that the operator failed to conduct the required daily idle speed checks as stipulated in the aircraft checklist. The measured idle speed of 700–800 rpm was substantially lower than the checklist's specified range of 1,400–1,600 rpm.