Originally posted by MajIssue
Hypoxia... Lack of O2 to the brain causes a progressive loss of cognative function culminating in loss of consciousness and eventually DEATH. In the RW the FAA requires oxygen equipment on unpressurized aircraft that fly at altitudes above 10K MSL (I seem to remember that the actual figure is 14K but I could be wrong).
AR 95-1 states the following as to the use of O2. Not sure what the FAA rules are. but are probably the same.
8–7. Oxygen system
See FM 3–04.301 for restrictions on use of oxygen. Approved oxygen systems will be used as follows:
a. Unpressurized aircraft. Oxygen will be used by aircraft crews and occupants for flights as shown below:
(1) Aircraft crews.
(a) On flights above 10,000 feet pressure altitude for more than 1 hour.
(b) On flights above 12,000 feet pressure altitude for more than 30 minutes.
(2) Aircraft crews and all other occupants.
(a) On flights above 14,000 feet pressure altitude for any period of time.
(b) For flights above 18,000 feet pressure altitude, oxygen prebreathing will be accomplished by aircrew members.
Prebreathing may utilize either 100 percent gaseous aviator’s oxygen from a high pressure source, or an onboard oxygen generating system (OBOGS) that supplies at least 90 percent oxygen in the inspired gas. Prebreathing will be for not less than 30 minutes at ground level and will continue while en route to altitude. In those extraordinary cases where mission requirements dictate rapid ascent, commanders may authorize shorter prebreathing times on a case-bycase basis, with the realization that such practice increases the risk for developing altitude decompression illness.
Return to NORMAL OXYGEN (pressure demand regulator, gaseous oxygen-equipped aircraft) is authorized on descent below 18,000 feet pressure altitude, provided continued flight will not exceed this altitude.
b. Pressurized aircraft.
(1) In flight, cabin pressure altitude will be maintained at or below 10,000 feet.
(2) As a minimum, a 10-minute emergency supply of oxygen will be available to all occupants when the aircraft is above 14,000 feet pressure altitude. Additional emergency oxygen will be on board when factors such as terrain, weather, or fuel consumption prevent descent to 10,000 feet cabin pressure altitude, in the event of depressurization.
Above 25,000 feet pressure altitude, oxygen masks will be connected and readily available.
(3) If pressurization is lost in flight above 14,000 feet pressure altitude, descent will be made immediately to a cabin pressure altitude of 10,000 feet or below. Thereafter, the provisions of paragraph a above apply.
