A Royal Australian Air Force (RAAF) Hercules aircraft was forced to make an emergency landing at Richmond Air Base when one of its engines caught fire.

The aircraft, with eight crew, was performing flight training near Lake Cargelligo when its second engine shut down and its flaps deployed at a 50% position.

Aircrew put on oxygen masks due to smoke and fumes inside the aircraft and were taken to military hospitals for precautionary checks, according to the Sydney Morning Herald.

An investigation is expected to be conducted into the incident.