Before servicing any aircraft, consult the specific aircraft maintenance manual to determine the proper type of servicing equipment to be used. Two persons are required to service an aircraft with gaseous oxygen. One man should be stationed at the control valves of the servicing equipment and one man stationed where he can observe the pressure in the aircraft system. Communication between the two men is required in case of an emergency. Aircraft should not be serviced with oxygen during fueling, defueling, or other maintenance work which could provide a source of ignition. Oxygen servicing of aircraft should be accomplished outside hangars.
Gaseous oxygen is chemically stable and is nonflammable; however, combustible materials ignite more rapidly and burn with greater intensity in an oxygen rich atmosphere. In addition, oxygen combines with oil, grease, or bituminous material to form a highly explosive mixture which is sensitive to impact. Physical damage to, or failure of, oxygen containers, valves, or plumbing can result in explosive rupture, with danger to life and property. It is imperative that the highest standard of housekeeping be observed in handling oxygen and that only authorized persons be permitted to service aircraft.
In addition to aggravating the fire hazard, liquid oxygen will cause severe "burns" (frostbite) if it comes in contact with the skin because of its low temperature. (It boils at -297° F.)
Only oxygen marked "Aviators Breathing Oxygen" which meets Federal Specification
BB-0-925a Grade A or equivalent may be used in aircraft breathing oxygen