- (a) If certification with supplemental oxygen equipment is requested, the equipment must meet the requirements of this section and §§ 25.1443 through 25.1453.
- (b) The oxygen system must be free from hazards in itself, in its method of operation, and in its effect upon other components.
- (c) There must be a means to allow the crew to readily determine, during flight, the quantity of oxygen available in each source of supply.
- (d) The oxygen flow rate and the oxygen equipment for airplanes for which certification for operation above 40,000 feet is requested must be approved.