On 17 November 2007 a Boeing Company 737-7Q8 aircraft,
registered VH-VBC, with two flight crew, four cabin crew and 145
passengers was being operated on a scheduled passenger service from
Coolangatta, Queensland to Melbourne, Victoria. During the takeoff,
the Master Caution system activated and the right BLEED TRIP OFF
light illuminated. The pilot in command, who was the pilot flying,
elected to continue the takeoff. Once airborne the Bleed Trip Off
non-normal checklist was actioned. The right engine bleed could not
be reset with the effect that, when above flight level (FL) 170
(17,000 ft above mean sea level), only the left engine bleed air
was available for airconditioning and cabin pressurisation.
At FL318 during the climb, the flight crew observed the left PACK
TRIP OFF light illuminate, followed by a rapid loss in cabin
pressure and the cabin rate of climb indicator showing a rate of
climb of about 2,000 ft/min. The crew fitted their emergency oxygen
masks, commenced the Emergency Descent checklist and began a rapid
descent to 10,000 ft. During the descent, the cabin altitude
exceeded 14,000 ft, at which time the passenger oxygen masks
deployed automatically. The aircraft was diverted to Brisbane for
landing. There were no reported injuries to passengers or crew and
no damage to the aircraft.
The investigation found that a combination of technical faults
contributed to the loss of pressurisation and identified a number
of other safety factors relating to operational procedures and
cabin crew knowledge of the passenger oxygen system.
The operator conducted an internal investigation of the incident
and carried out a number of safety actions as a result. Those
actions included the enhancement of a number of the operator's
manuals and the amendment of the operator's cabin safety recurrent
training. In addition, the operator's passenger oxygen use in-cabin
brief was enhanced to include advice that oxygen would flow to
passengers' masks even if the associated bag was not inflated.