Lomapaseo. .. .Sorry, but you are wrong.. .. .Obviously one tries top keep the pax alive, but decompression does not affect the max altitude. There is always sufficient O2 on-board to deal with pax oxygen requirements for an amount of time. The amount of time varies from operator to operator as a function of the routes they fly and the amount of time they may need to operate above 10,000ft (at which point pax usually come off oxygen following a cabin altitude excedance.. .. .The operator I fly for has extra O2 on board to allow operation over routes with extended operation over the Hindu Kush, for example.. .. .The factors determining max alt capability are the ones mentioned in previous posts.. .. .TB