The parts, including fan blades, discs and a rotor shaft, could help explain why the engine failed.

At the same time it is possible to control the rotor by tilting the rotor shaft (helicopter) in the desired direction of flight.

The steel frame also carries the engine, semi-exposed behind the accommodation and connected to the main rotor shaft by a belt drive.

All the engine accessories, like the fuel pump and electrical alternator, ran directly off the rotor shaft.

Three of the lines caught and wrapped around the rotor shaft before the tired old material gave way and shredded.

Its engine mangled, the rotor shaft seized and one blade snapped off.

The vibrations resulted when the rotor shafts were moved 17 degrees forward from vertical.

Instead, the rotor shaft is attached directly to the generator, which spins at the same speed as the blades.

The hub is fixed to the rotor shaft which drives the generator through a gearbox.

This system is normally composed of two blades that meet just under a common flapping, or teetering hinge at the rotor shaft.