The man's amateur-built Twinstar aircraft came down in a paddock about 800m from the Bombala Airstrip.

Emergency crews received a triple-0 call, saying a plane had crashed west of the airport, a NSW Ambulance Service spokesman said.

Police, fire and ambulance service personnel arrived to find the pilot had freed himself.

He was taken to Bombala Hospital, where he was assessed before the NSW Ambulance rescue helicopter was called from Albion Park.

A doctor and paramedic on board stabilised the patient at Bombala Hospital before he was airlifted to hospital in Canberra. He was being treated for internal chest injuries and suspected spinal injuries and was in a serious but stable condition.

His injuries were not thought to be life threatening, police said.

While an investigation into the crash scene, at a Bombala property called Cascade, began, eyewitnesses said they believed the aircraft's engine had failed.

A police spokesman said the man was flying the light aircraft over Bombala when its engine failed. He glided the plane towards the air-strip but crash-landed short of the runway.

A spokeswoman for the Australian Transport Safety Bureau said it would not be investigating the incident.