Pacplyer,
It was a long distant memory trying to chase leaks on a B747. It is hard enough finding them on a B757! I would fire toolbox up now, to look for leak rates, but if any of my mates were reading this thread from work, it would be the biggest flame in history on my return!
I was called back to top up crew O2 the other day, that was 80psi above min dispatch, because of the possibility of flying over high terrain, so I find it hard that QANTAS would release a leaky aircraft on a long sector. Unless, because of the leak, they filled the tanks upto max. In my previous life, 1750 to 1800psi was max and now we will top up at 1300ish to about 1700psi. If they had a known problem and it was on a long sector, you would be inclined to get as much as you could in, which, if there was a problem somewhere in the system, would increase the chance of a failure to a weak point.
I still find it hard to believe that a bottle would let go without some external force, other than dropping from its mount, influencing a rupture of the bottle.
As I have said before, they are solid lumps!
******DISCLAIMER******** something within the cargo pallet went off and through the sidewall panel, hit the bottle/regulator at speed and caused the rupture.*********SPECULATION OVER**********