Read the aircraft maintenance manual for procedures on servicing the aircraft's oxygen system. Strictly follow the manual's aircraft-specific directions. The maintenance manual provides the location of the aircraft's oxygen filler valve and pressure-temperature chart.
Locate the oxygen service cart near the aircraft. Oxygen bottles are painted green and have "Aviators' Oxygen" stenciled on the bottles' sides.
Open necessary aircraft panels to access the filler valve. Remove the filler valve's cap.
Uncoil the oxygen fill hose. Remove the plug from the hose's end fitting.
Purge the fill line of any contaminants. Choose the service cart bottle with the lowest pressure. Slowly open the oxygen bottle's valve by rotating it counter-clockwise until oxygen flows through the fill line. Close the valve.
Connect the fill line to the aircraft's filler valve. Tighten the connection carefully.
Slowly open the valve on the service cart oxygen bottle with the lowest reading pressure. Gradually let the oxygen flow from the cart into the aircraft until the pressures equalize. Close the valve. The aircraft's oxygen system will get excessively hot if the oxygen is allowed to flow too quickly (See References 3).
Slowly open the valve on the service cart oxygen bottle with a higher pressure. Let the oxygen flow into the aircraft's system. Close the service cart bottle's oxygen valve when the aircraft's oxygen system pressure equals that specified by the maintenance manual.
Remove the oxygen fill line from the aircraft's filler valve. Re-install the filler valve cap. Install the fill line plug.
Re-install the aircraft access panels.
Enter the oxygen fill information into the aircraft's maintenance record.
