Hi BOAC
I would, however, take issue with Nigel on the prospects of "survive for a long time on Oxy Masks at cruise altitude" since the partial pressure of oxygen at that altitude is too low to support consciousness for very long on a pax mask and hence the need to get down PDQ
I did say "survive"
Not necessarily conscious
My point was not that anybody should or would stay @ Cruise Alt, but there is no massive urgency for those on Oxy.
Thanks for your reply to 'Tourist'... I would add that:
I am unable to refrain from pointing out that your quote of 3 mins above 20k is total re brain damage.
is not what I said... I said:
...at cruise altitude, ... and 3mins to possible brain damage. Very roughly, once below 20K' the brain damage issue has gone. So you can see the priority...
i.e. at a Cruise Alt (maybe >40K') and ~3mins, Brain Damage starts becoming a factor. I am not talking the young, fit or steely eyes fighter jock like BOAC, but the old / sick who might already be on supplementary oxygen at 8K' cabin alt. Thanks for the link anyway which I shall read...