Australian pilot falls asleep mid flight | Flies 60 miles past destination

The Australian Transport Safety Bureau (ATSB) said in an investigation report released today that mild hypoxia likely played a part in an incident when the pilot of a Cessna Caravan fell asleep at the controls in July last year. The pilot was ferrying C208B VH-DQP at 11,000 feet from Cairns to Redcliffe when it overflew its destination and failed to respond to ATC radio calls for 40 minutes. An RFDS King Air, FlyDoc 425, was sent to intercept the aircraft east of Brisbane, where the RFDS crew tried to trigger the Caravan's TCAS, but the pilot remained unresponsive.

After flying 60 nm past Redcliffe, the pilot regained consciousness, but appeared confused in communications with ATC. Eventually, ATC guided the pilot to land the aircraft at Gold Coast Airport. The pilot had earlier requested a climb to 11,000 feet from 10,000 due cloud, and had begun to use the Caravan's supplemental oxygen intermittently, whereas pilots of unpressurised aircraft flying above 10,000 are required to be on oxygen constantly.

The ATSB found that inadequate sleep likely produced fatigue and that intermittent oxygen use at 11,000 feet likely caused mild hypoxia, which exacerbated the fatigue and contributed to the pilot falling asleep.

Sources

• ATSB: Final report AO-2020-032
• ATSB: Aviation investigations index

“The pilot was likely experiencing a level of fatigue due to inadequate sleep the night before and leading up to the incident.”

Accident Facts

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