CASA Orders Audit To Airline's Maintenance Procedures

It's official. Investigators with Australia's Civil Aviation Safety Authority have ruled an exploding oxygen bottle was behind an incident onboard a Boeing 747-400 flying for Qantas, in which a two-meter-long hole was blown out the side of the plane's fuselage.

As ANN reported, Flight 30 from Hong Kong to Melbourne diverted to Manila July 25 after those onboard heard a loud bang, and the plane's flight crew noticed the cabin was losing pressure at FL290. The jetliner later made a safe landing, with no reported injuries to those onboard.

As the flight's 346 passengers and 19 crewmembers exited the plane, those on the ground discovered the 747's right leading edge wing-to-body fairing was missing, and a five-foot hole was present in the cargo area fuselage wall behind it. Luggage could be seen jutting from the hole.

Within days, investigators said they suspected an oxygen bottle was behind the explosion... noting one of the canisters stowed onboard the airliner, and near the damaged area, was missing. Last week, officials with CASA and the Australian Transport Safety Bureau -- which oversaw the investigation -- issued their preliminary report, stating an O2 bottle "sustained a failure," according to The Wall Street Journal.

The account of what came after that "failure" is interesting. According to the ATSB report, the explosion propelled the bottle into the floor of the passenger cabin, as the blast itself created the hole in the fuselage. The bottle then impacted the top of the cabin's ceiling, and fell back down... first through the hole in the cabin floor, then the larger hole in the fuselage skin.

The rupture also damaged several cables, including the control cables running from the co-pilot's yoke to the ailerons on the jumbo jet's right wing. Control of the aircraft was not compromised, however, due to duplicate controls on the pilot's side of the plane that were not affected by the blast.

The bottle that exploded was one of 13 carried onboard the 747, used to stow oxygen for emergency use in the event of cabin depressurization. A number of passengers said they were unable to use their cabin oxygen masks while the plane made its emergency descent.

One question remains for investigators, as they work to make this "preliminary" report a definitive one: what caused the oxygen bottle to fail?

For now, investigators aren't saying.... but the ATSB has issued two related safety advisories, calling for operators to pay close attention to the circumstances listed in the report, and to keep up on mandatory O2 bottle inspections and repairs.

Qantas told the WSJ it welcomed the ATSB's report. "Our own investigations agree with the ATSB's preliminary conclusions," Qantas CEO Geoff Dixon said, adding the airline has already inspected the oxygen systems on its other 747-400s.

And more inspections are probably coming. On Monday, CASA announced the results of a formal review of maintenance practices at Qantas... noting a review conducted over the past month "uncovered signs of emerging problems" in Qantas's maintenance procedures, and that the authority will audit the carrier.

"The review found maintenance performance within Qantas is showing some adverse trends and is now below the airline's own benchmarks," continued Mick Quinn, CASA's deputy chief executive officer of operations.

CASA added none of its findings were tied to the July 25 O2 bottle incident, and none of the problems led to an increase in the number of safety-related incidents. Still, the findings are a blemish against the airline's reputation as a safe carrier; Qantas has never suffered a fatal accident since it switched to an all-jet fleet in the 1960s.

Dixon took steps Monday to remind the flying public of that fact. "These issues are not about safety or compliance and we are working to bring our network performance back to the standards which have earned us a reputation as one of the best and most reliable airlines in the world," he said.

He conceded the airline's performance standards were "significantly impacted" by a labor dispute between the carrier and its 1,500 aircraft mechanics, which was settled last month.

The audit is expected to last three months, and will include full onsite inspections of one plane type each from Qantas' fleet of Boeing 737, 747 and 767s. Inspectors will also thoroughly review the maintenance documentation for each checked aircraft.

CASA said the audit will show "whether the existing lines of authority and control over maintenance within the airline are delivering the best possible outcomes."

FMI: www.qantas.com, www.casa.gov.au, www.atsb.gov.au/