Loss of control involving Cessna 172L, VH-ROA, Cape Barren Island, Tasmania

The pilot indicated prior to departure that his intention was to track from Launceston directly across Bass Strait to Tyabb, rather than via the Bass Strait Islands. The aircraft departed Launceston with an air traffic control clearance appropriate to that intention.

After being airborne for about one and a half hours, the aircraft approached over Cape Barren Island, although the pilot had not indicated that he was diverting from the planned track. Two very low circuits were flown in the vicinity of the airstrip and while still flying low, the pilot asked the front seat passenger to tell him what he could see below the aircraft.

The survivor, who was sitting in the right rear seat, gained the impression that the pilot could not see and that he was unwell, although apparently not in pain. He did not respond when she spoke to him. She undid her seat belt, leant over the pilot and asked if the passengers could do anything to assist. The pilot did not reply and his eyes appeared glazed. She shook him, but almost immediately the aircraft descended steeply to the ground.

From the damage sustained by the aircraft and the lack of any significant ground slide, it was assessed that the aircraft had stalled from probably no higher than 150 feet and had impacted the ground in a steep nose down and left wing low attitude. Both wing flaps were found to be extended, suggesting that the aircraft was in a landing configuration.

Medical tests and examination were unable to substantiate any cardiac or cerebral event which might have accounted for the pilot's incapacitation. There are indications, however, which suggest that the incapacitation was as a result of an insulin related condition. The pilot had successfully passed his last Civil Aviation medical examination in December 1991.

Significant Factors

The following factor was considered relevant to the development of the accident:

1. The pilot apparently suffered a subtle form of incapacitation which progressively reduced his ability to control the aircraft.