Pilot Report
The pilot of a Hughes 369D reported that the helicopter was cruising at an altitude between 300 and 500 feet above the surface. He heard a loud 'pop' and then the engine spooled down rapidly. According to the pilot, there was no prior indication of a problem until the engine abruptly lost power.
Autorotation and Landing
Upon the loss of engine power, the pilot initiated an autorotation and landed on a sloped portion of a highway. After touchdown, the right skid dropped approximately 20 inches, causing the main rotor blades to strike the tailboom.
Post-Accident Examination
No preimpact mechanical discrepancy was found during the examination of the helicopter. The engine and other components did not exhibit any failure or malfunction that could have caused the power loss.