Supplemental oxygen - pressurised aeroplanes not certified above 25 000ft

[Luckystar77]

Hi everyone,

I was looking at CAT.IDE.A.235(e) which says "oxygen supply (...) in the case of aeroplanes not certified to fly at altitudes above 25 000 ft, may be reduced to the entire flying time between 10 000ft and 13 000ft cabin pressure altitudes for all required cabin crew members and for at least 10% of the passengers if, at all points along the route to be flown, the aeroplane is able to descend safely within 4 min. to a cabin pressure altitude of 13 000ft."

Let's say my route (and aircraft) meets the requirement of emergency descend within 4 minutes and the aeroplane (without oxygen system installed) requires 2 cabin crew members, how many portable supplemental oxygen bottles would I have to carry in passenger compartment in order to comply with the regulation?

Does it have to be one per each required crew member plus at least the additional bottle for passengers who might need it? Or is it enough to have one bottle appropriately charged with one or more outlets for masks?

Any comments appreciated...

[No Fly Zone]

It requires accommodation for ALL crew and 10% of PAX. Depends upon the O2 bottle size, where located, how connected etc. The implied, but unspoken question is whether you can (Safely get down to Cabin Altitude 13,000 Ft. within four minutes. I can think of several places in Europe where a quick dive down to 13,000 Ft. would be a Very Bad idea. Perhaps the better answer is to plan your route to avoid the extremes when possible and carry a good bit more O2 than the absolute minimum required. (Flying with minimums of anything will eventually hurt you.) You may also want to increase your personal knowledge of cabin crew's training and their ability to pass O2 to those who most need it. And as the head Safety Representatives on any given flight in those possibly limiting conditions, the pilots (and then the cabin crew) must have full access to 100% O2 at all times. Think it through... A slightly hypoxic passenger for slightly more than four minutes probably will not die and certainly cannot crash the airplane. A hypoxic pilot can and probably will, unless s/he gets a good O2 supply, quickly. The flight deck needs alert, well oxygenated pilots at all times, not slap-happy campers who 'think' they can out-climb that mountain just ahead. Ouch!