The pilot was conducting a night freight operation, carrying newspapers from Darwin to Alice Springs via Tindal and Tennant Creek. The flight from Darwin to Tindal was uneventful and the aircraft subsequently departed Tindal at 0219 am local time.
On departure, the pilot reported that he mistakenly established the aircraft on a track 30 degrees right of the correct track. After the pilot had levelled the aircraft at the intended cruising altitude, he fell asleep. As the flight progressed, the pilot occasionally woke up and made slight corrections to the heading, but he did not identify the 30 degree error. When the pilot realised that he should be on descent to Tennant Creek, he selected the appropriate frequencies, however the aircraft's navigation instruments did not provide any directional information. Believing that the aircraft was west of Tennant Creek, the pilot turned the aircraft and flew east, climbing to 14000 ft in an attempt to improve the range of the aircraft's navigation instruments. The instruments still did not show where Tennant Creek was, so the pilot decided to continue to Alice Springs at his flight planned altitude. At the time that the aircraft should have been approaching Alice Springs, the pilot selected the appropriate frequencies for the Alice Springs navigation aids. The aircraft's navigation instruments did not indicate the direction of Alice Springs, even though the pilot again climbed the aircraft to 14000 ft. The pilot reported that as the aircraft was now running low on fuel, the pilot decided to conduct a precautionary search and landing. The pilot advised Adelaide Flight Service on high frequency radio that he intended to land the aircraft on a dry salt lake.
The aircraft sustained minor damage during the landing however the pilot was not injured. He then activated the Emergency Locater Transmitter, and the aircraft was subsequently located 370 km WSW of Alice Springs. The company reported that its roster for night freight pilots has operated satisfactorily for around four years, with no reported serious fatigue problems. The pilots usually operate a one night shift every eight days, and the three days before the night shift are either days off or standby days. The pilot involved in this incident had done no flying on his rostered standby day, and therefore had had three full days off prior to signing on late in the evening of the day before the accident. He stated that he normally tried to sleep in on the morning before the night shift, and then get a couple of hours sleep in the afternoon. However, on the morning before he signed on for the night flight he was unable to sleep in and was then also unable to sleep in the afternoon. Consequently, by the time he signed on for the flight, the pilot had been awake for approximately 13.5 hours. The aircraft was not equipped with GPS. It is probable that the pilot's lack of sleep prior to signing on for the flight resulted in an increased level of fatigue. The increased fatigue may have contributed to the pilot selecting the incorrect heading on departure from Tindal and his subsequent lapses into sleep. Once the aircraft was out of range of the Tennant Creek and Alice Springs navigation aids and because of the lack of terrain features visible at night, there was no information available to the pilot to help him identify his position. The company is currently ensuring that flight crews have access to GPS equipment. The company is also drafting detailed standard operating procedures regarding sleep management, and these procedures will be included in the operations manual.