Le forum des ULM, et des ELA, LSA, VLA, et de tous les autres aéronefs biplaces et monoplaces légers

hv74 a écrit :....Nous sommes tous deux plongeurs , qualifiés nitrox !....

The FAA requires that all pilots flying their aircraft above 12,500 feet for 30 minutes or longer or at 14,000 feet or above during the entire flight must use supplemental oxygen - ref FAR 91.211. Passengers must have oxygen available (but don't need to use it) above 15,000ft. The amount required (reference: FAR 23.1447) is 1 liter of oxygen per minute for every 10,000 feet. For example, at 18,000 feet there should be a flow of 1.8 liters per minute of oxygen available via a standard breathing device. The FAA requires there should be a device so attached to each breathing device that visually shows the flow of oxygen. The FAA also recommends that oxygen be used at night at altitudes over 5,000 feet.

A mask (rather than a cannula) is mandatory above 18,000 feet (FAR 23.1447). However, this regulation start with the words "If oxygen dispensing units are installed" which most likely means it was written to cover installed systems, whose operating limitations are in the Aircraft Flight Manual and legally must be followed. Portable systems appear to be unregulated, as is the vast majority of "portable" aviation equipment applicable to Part 91 (private flight) operations. I have tested cannulas to 20,000 feet and they worked fine, delivering a ~ 95% oxygen level , but one needs to breathe very deliberately and this would not be recommended for children and other potentially "not responsible" passengers.