Pilot's Account
The helicopter pilot reported that after preflight checks and a normal hover at 3 feet, he rotated 180 degrees to transition out. With everything in the green, he added full power, lowered the cyclic, and slightly raised the collective to begin forward movement. As the helicopter climbed to about 15-17 feet, a coughing sound was heard, followed by silence as the engine quit. The pilot stated, "I tried to get it back on the ground as flat and level as possible. You can not auto[rotate] at 17 feet."
Height/Velocity Considerations
A Federal Aviation Administration publication explains that a height/velocity (H/V) diagram, published for each helicopter model, shows critical combinations of airspeed and altitude should an engine failure occur. Operating within the crosshatched or shaded areas of the diagram may not allow sufficient time for the transition from powered flight to autorotation.
Wind Effects Guidance
The helicopter flight manual emphasizes that wind effects on takeoff and landing are important factors. In planning critical operations, winds can assist landings and takeoffs from unobstructed areas. However, if a gust decreases during final approach or initial takeoff, the helicopter may rapidly settle. The manual also notes the 'lee' effect of wind over hills, ridges, and obstacles, which produces downdrafts that particularly affect the initial phase of takeoff or the final phase of landing.
Postaccident Examination
A postaccident examination of the helicopter and the accident site revealed the helicopter facing north in an open, flat, unobstructed field. Buildings were present to the south of the field. No anomalies were found with respect to the helicopter. Winds reported at the time were from 200 degrees at 17 knots, gusting to 22 knots, with a peak wind of 210 degrees at 26 knots.