The Australian Transport Safety Bureau has issued a caution about fatigue today coincident with releasing the final investigation report into a Piper PA-31 incident in Bass Strait.
Navajo VH-TWU was on a freight run from Devonport to King Island in November last year when the pilot fell asleep, causing the aircraft to overshoot the island by 42 nm.
The pilot had left Moorabbin at 2300 the previous night and flew to Devonport, where he helped unload the freight before starting a three-hour rest. He began preparing for the next leg of the run at 0500 and departed at Devonport at 0620.
"The Piper PA-31-350 aircraft had reached top of descent into King Island when the pilot, who was the only person on board, started to feel tired and quickly fell asleep," the report states. "After several unsuccessful attempts by ATC and other pilots in the area to contact the pilot, he awoke and advised ATC operations were normal and that he was turning back to King Island.
"The aircraft landed without further incident. However, after talking with the operator, the pilot then flew from King Island to Moorabbin to complete his shift."
The pilot had been awake for around 24 hours and had been unable to sleep during a scheduled rest period before the flight. ATSB analysis showed the pilot’s fatigue level was high enough to effect performance and that even if the pilot had been able to sleep during his rest period he still would have been fatigued to a similar degree.
"This investigation highlights the need for pilots to assess their level of fatigue before and during their flight,” said ATSB Executive Director Nat Nagy. “Before commencing night operations pilots are encouraged to modify their usual sleep routines to ensure they are adequately rested.”
The ATSB also singled out the aircraft operator, VortexAir, for attention, saying "the operator did not put in place measures to ensure the pilot was fit to continue the shift. This resulted in the pilot continuing to fly the aircraft while still being fatigued to a level known to affect performance."
“Just as it is the pilot’s responsibility to use rest periods to get adequate sleep and to remove themselves from duty if they feel fatigued," Nagy said, "it is also incumbent on operators to implement policies and create an organisational culture where flight crew can report fatigue and remove themselves from duty in a supportive environment."
The full investigation report is on the ATSB website.