Aviation safety investigators said on Aug. 29 that an exploding oxygen cylinder ripped a large hole in a Qantas Boeing 747 on July 25, but said they still don’t know why the air tank failed, according to the Australian Transport Safety Bureau’s (ATSB) preliminary report on the in-flight emergency over the South China Sea. The crew was able to make an emergency landing at Manila’s airport with no injuries among the passenger and crew. One of 13 emergency oxygen cylinders installed on the jumbo jetliner. The investigation is now focused on pinpointing the cause. The explosion blew a hole in the fuselage 6.5 feet wide and 5 feet high. Qantas said the ATSB report confirmed the air carrier’s suspicions. "We will continue to assist the ATSB to ensure that factors that may have contributed to the incident are understood and that any corrective actions ultimately identified are implemented,” said Qantas. The air carrier completed an inspection of the oxygen systems across its B747-400 fleet on Aug. 1, confirming there were no additional safety issues with the oxygen cylinders.