On 25 July 2008, at 0922 local time, a Boeing Company 747-438 aircraft (registered VH-OJK)
with 365 persons on board, departed Hong Kong International airport on a scheduled passenger
transport flight to Melbourne, Australia. Approximately 55 minutes into the flight, while the
aircraft was cruising at 29,000 ft (FL290), a loud bang was heard by passengers and crew,
followed by the rapid depressurisation of the cabin. Oxygen masks dropped from the overhead
compartments shortly afterward, and it was reported that most passengers and crew commenced
using the masks. After donning their own oxygen masks, the flight crew carried out the 'cabin
altitude non-normal' checklist items and commenced a descent to a lower altitude, where
supplemental breathing oxygen would no longer be required. A MAYDAY distress radio call was
made on the regional air traffic control frequency. After levelling the aircraft at 10,000 ft, the
flight crew diverted to Ninoy Aquino International Airport, Manila, where an uneventful visual
approach and landing was made. The aircraft was stopped on the runway for an external
inspection, before being towed to the terminal for passenger disembarkation.
Subsequent inspection of the aircraft by the operator's personnel and ATSB investigators,
revealed an inverted T-shaped rupture in the lower right side of the fuselage, immediately beneath
the wing leading edge-to-fuselage transition fairing (which had been lost during the event). Items
of wrapped cargo were observed partially protruding from the rupture, which extended for
approximately 2 metres along the length of the aircraft and 1.5 metres vertically.
After clearing the baggage and cargo from the forward aircraft hold, it was evident that one
passenger oxygen cylinder (number-4 from a bank of seven cylinders along the right side of the
cargo hold) had sustained a sudden failure and forceful discharge of its pressurised contents into
the aircraft hold, rupturing the fuselage in the vicinity of the wing-fuselage leading edge fairing.
The cylinder had been propelled upward by the force of the discharge, puncturing the cabin floor
and entering the cabin adjacent to the second main cabin door. The cylinder had subsequently
impacted the door frame, door handle and overhead panelling, before falling to the cabin floor and
exiting the aircraft through the ruptured fuselage.
The investigation is continuing.
Download preliminary report [PDF
2.5 MB]
Aviation Safety Advisory Notice [ AO-2008-053-SAN-006 ] [ AO-2008-053-SAN-007 ]
