Engine Power Loss During Vertical Takeoff Leads to Helicopter Rollover After Skid Strikes Fuel Jug (N8306F)

Accident Sequence

The pilot reported lifting off vertically and turning the helicopter downwind toward the first sling load. As the helicopter reached an altitude of 70 to 80 feet above ground level, the engine lost power. The pilot immediately initiated a hovering autorotation. Just before touchdown, the left side landing skid collided with a 17-gallon fuel jug. The impact caused the helicopter to roll to the right, and the right side landing skid struck the ground and collapsed. The helicopter continued rolling until it came to rest on its right side.

Post-Accident Investigation

A post-accident examination of the engine revealed that the pneumatic line at the fuel control unit was disconnected. The fuel control had been replaced two days prior to the accident. The mechanic who performed the replacement stated that all B-nuts had been properly torqued. Investigators inspected the pneumatic line, its B-nut and threads, and the mating connection on the fuel control for damage. No evidence of damage was found that would indicate how the B-nut could have backed off the fuel control connection if it had been properly torqued.