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 take-off, 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 take-off. 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 air-conditioning 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.