Incident Overview
A helicopter on a maintenance test flight was operating at an altitude of approximately 300 to 400 feet above ground level. The flight crew, consisting of the pilot and two mechanics, had begun tracking the rotor blades at a speed of 130 to 140 miles per hour when they experienced a sudden left yaw. Simultaneously, an engine-out warning light and audio alert activated.
Emergency Maneuver
The pilot initiated an autorotation and landed in an open field. During touchdown, the tail skids made contact with the ground, causing the main rotor blades to strike and sever the tail boom.
Post-Incident Examination
Following the incident, the engine was run up and performed satisfactorily. The fuel system was disassembled and inspected, revealing no evidence of contamination or obstruction. Investigators drained 10 gallons of fuel from the helicopter's fuel tanks, including one gallon of fuel classified as unusable.
Manufacturer's Assessment
According to the helicopter manufacturer, the total fuel quantity found is considered a low level. They stated that under such conditions, the pilot should have been planning to land as soon as practical.