Beechcraft A36, VH-PGG, Canberra Airport, Australian Capital Territory, on 30 October 1988

Circumstances:

About 45 minutes after DEPARTURE the radio communications, and radio navigation aid signals became weak, and a squeal was heard through the audio system. The pilot realised that he had an electrical problem, but he did not check the ammeter, or the positioning of the alternator switch believing that he had turned the switch on after start. Approaching Canberra, the pilot was given an airways clearance to maintain 4000 feet. All communications were then lost. He squawked code 7600, and proceeded as per the flight plan to Canberra, maintaining VMC as all his navaids had now ceased to operate. On arrival, the pilot observed that emergency services were being positioned along Runway 30. He commenced an approach from 4000 feet, (2112 feet above ground level), approximately 1000 feet above normal circuit height. The pilot now felt under a great deal of stress and was becoming task saturated. On downwind he placed the landing gear selector in the down position but failed to check if the gear had extended. Turning onto final approach he selected the flaps down, which failed to operate. He then noticed that the landing gear position lights were not illuminated, but he did not verify the landing gear position with the manual extension handle. The Tower directed a green light at the aircraft which convinced the pilot that his landing gear must be down. Shortly after touchdown the partially extended landing gear collapsed. The aircraft was found to have a completely discharged battery. The engine was started using ground power and the alternator operated normally, which recharged the battery. The electrical and radios systems were also found to function normally.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The pilot did not notice that the alternator was not supplying charge to the battery.

2. The aircraft suffered a loss of electrical power in flight.

3. The pilot did not carry out appropriate trouble checks to determine the cause of the electrical problem.

4. The pilot became task saturated and failed to ensure that the landing gear was down and locked.