Hughes 369D crash near Kammenniemi, Pirkanmaa, Finland

The Hughes 369D was flying at about 60 metres on an aerial sawing flight, clearing branches near power lines, when the engine lost power and the pilot made an emergency landing. The pilot suffered minor injuries and the helicopter was destroyed. The Safety Investigation Authority traced the loss of power to a maintenance error that left a B-nut loose in the compressor delivery air pressure sensing lines.