Accident Narrative
The pilot reduced the helicopter's airspeed to 30 knots indicated airspeed using 50 to 60 percent power at an altitude of 700 feet above ground level. Shortly thereafter, the pilot heard two beeps from the engine out warning horn and observed the illumination of engine out annunciator lights. The pilot also noted that the turbine needle was dropping. In response, the pilot lowered the collective fully and lowered the nose of the helicopter. Despite these actions, the helicopter descended while yawing left and right until it contacted a creek bed.
Inspection Findings
Examination of the aircraft revealed that the PC line was broken just past the 90-degree bend where it connects to the gas producer fuel control. The other end of the break was concealed by a B-nut. Metallurgical testing determined that the line had failed due to fatigue. Additionally, areas of fretting and dimpling were found on the line.
Previous Removals
The engine in the helicopter, which bore registration N99TV, had been removed from the aircraft on November 14, 1983, and again on September 6, 1984. Each removal required unfastening and fastening of the PC line.