Monday, November 22, 2010

ATSB Final Report: July 2008 Qantas Boeing 747 depressurization accident

by B. N. Sullivan

The Australian Transport Safety Bureau (ATSB) has issued a final report on the sudden decompression in flight of a Qantas Boeing 747-400 on July 25, 2008.  The accident happened during the cruise phase of Qantas Flight QF30, which was en route from Hong Kong to Melbourne.  The flight diverted to Ninoy Aquino International Airport, Manila where it landed safely.  There were no serious serious injuries to those on board, however the aircraft's fuselage ruptured over an area measuring approximately 2 x 1.5 m (6.6 x 4.9 ft).

The ATSB investigation determined that the fuselage rupture "had been induced by the forceful bursting of one of a bank of seven oxygen cylinders located along the right side of the cargo hold," of the oxygen cylinders that provide the emergency supplementary oxygen supply for passengers.
An analysis of the damage produced by the ruptured cylinder showed that the force of the failure had projected the cylinder vertically upward into the aircraft's cabin, where it had impacted the R2 door frame, handle and the overhead panelling and structure, before presumably falling to the cabin floor and being swept out of the aircraft during the depressurisation. No part of the cylinder body was located within the aircraft, despite a thorough search.
The ATSB investigation "was unable to identify any particular factor or factors that could, with any degree of probability, be associated with the cylinder failure event."
Despite the inconclusive outcome of the investigation as to contributing factors, the associated engineering study did confirm that the cylinder type was fit-for-purpose.  There was no individual or broad characteristic of the cylinders that was felt to be a threat to the safety or airworthiness of the design.  Similarly, there was no aspect of the batch of cylinders produced with the failed item, which deviated from the type specification, or provided any indication of the increased potential for the existence of an injurious flaw or defect within that particular production lot.
In other words, in the opinion of the ATSB investigators, the rupture of the oxygen cylinder on Qantas Flight 30 was "a unique event and highly unlikely to happen again."

Here is the link to the full report: ATSB: Oxygen cylinder failure and depressurisation - 475 km north-west of Manila, Philippines, 25 July 2008, Boeing 747-438, VH-OJK

The report includes a number of photos showing the extent of the damage to the aircraft.

RELATED: Click here to view all posts about Qantas Flt 30 on Aircrew Buzz.