Originally Posted by
Lake1952
I would prefer that my cockpit crew test their oxygen supply to assure it works.
At my airline a functional check of all cockpit masks is required on the first flight of the crew day (i.e. not repeated at each turnaround). While the check is conducted "in container" i.e. the mask is not actually removed and donned, I have full confidence in the check other than it confirming that the gas being delivered is actually O2. I have to rely on ground servicing integrity for that.
To answer another poster's query, an additional pax mask is installed above every set of seats.
Regarding failure to use supplemental O2 in the case of depressurisation I'm going to go out on a limb and say that during even the worst case scenario, i.e. explosive depress at FL450 followed by a poorly flown emergency descent to an intermediate altitude due terrain followed by a further descent to 10000' within 30 minutes of initial depress, the risk of serious or lasting effects is very low except, perhaps, for physical injury due to unrestrained pax movements while unconscious, or rarer cases where an underlying medical condition is triggered by the resulting hypoxia.
My rationale:
While Time of Useful Consciousness at FL450 is quoted as 9-15 seconds (it may be less in affected people, think seriously unfit or heavy smokers) and is reduced by activity, think walking back to your seat, the time to actual unconsciousness is much longer. And the time to actual deleterious effects of hypoxia on brain or other cells is even longer still.
There are reports of passengers failing to refusing to don masks with no long-term or serious after-effects provided that the cabin altitude was reduced in the previously mentioned timely manner.
Now, I am not defending the position challenged by the OP. Safety-sensitive systems such as supplemental O2 systems should not be experiencing 25% failure rates and manufacturers and regulators should not be brushing aside genuine reports of such failures. O2 systems are installed for very good reasons but I get the feeling we are overstating the risk a little.
Ok, let the howling begin....