KEY POINTS:
An air safety investigator says it appears shrapnel from an oxygen cylinder explosion aboard a packed Qantas jetliner sheared off part of a door handle and knocked it half-way out of position.
The explosion last Friday during a flight from Hong Kong to Melbourne blew a large hole in the side of the Boeing 747-400.
Australian Transport Safety Bureau official Julian Walsh says "there was never any danger of the door opening" because it was designed never to open while the plane was in the air.
