The ATSB's final report into the terrain proximity caution
incident to the south-south-east of Canberra at 0544 am on 24 July
2004 has found that the flight crew of the Boeing 737 were affected
by fatigue and they misinterpreted the instrument approach chart
and entered incorrect data into the flight management computer.
The aircraft was being operated on an overnight service from
Perth to Canberra, when it proceeded beyond the limits of the
Church Creek Holding pattern, 10.9 NM south of Canberra. In doing
so the crew manoeuvred the aircraft closer to terrain than
intended. As a consequence the aircraft received a 'Caution
Terrain' message from the aircraft's enhanced ground proximity
warning system.
The crew had commenced a right turn back to the north towards
Canberra shortly before the 'Caution Terrain' message. They then
climbed the aircraft to a higher altitude.
The flight crew's fatigue was partly the result of an
airconditioning fault that led to hot cockpit conditions from Perth
to Canberra. Normal air traffic assistance was unavailable in
Canberra until 40 minutes after the scheduled 0530 am opening
time.
The aircraft operator has amended its procedures to require a
higher altitude for aircraft holding to the south of Canberra and
the chart publisher is amending charts to reduce the likelihood of
misinterpretation.
The ATSB initiated a category 3 investigation, which was
subsequently noted on the ATSB website in early August. The Bureau
released a preliminary report on this occurrence on 22 September
2004.
The final ATSB investigation report (
Aviation Safety Investigation Report 200402747) can be
downloaded from the website, or obtained from the ATSB by
telephoning (02) 6274 6478 or 1800 020 616.