The Australian Transport Safety Bureau (ATSB) released its Preliminary Factual report on the depressurisation of Boeing 747-438, VH-OJK, 475 km northwest of the Philippines.
On the basis of the physical damage to the aircraft’s forward cargo hold and cabin, it was evident that the number-4 passenger oxygen cylinder sustained a failure that allowed a sudden and complete release of the pressurised contents. The rupture and damage to the aircraft’s fuselage was consistent with being produced by the energy associated with that release of pressure. Furthermore, it was evident that as a result of the cylinder failure, the vessel was propelled upward, through the cabin floor and into the cabin space. Damage and impact witness marks found on the structure and fittings around the R2 cabin door showed the trajectory of the cylinder after the failure. (ATSB)