K. Make sure it has not been more than three years since the replacement oxygen cylinder had its last hydrostatic test.
NOTE: The last hydrostatic test date will be on a label near the top of the oxygen cylinder.
L. Remove cap, if installed, from airplane connection and examine to ensure fittings are clean and free of contaminants, thread chips, etc.
Feb 20/94 12-15-21 Page 202A/202B BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
M. Remove any lockwire or cotter pin which may be used to secure cap on fully charged oxygen cylinder. Slowly unscrew cap from cylinder and allow any trapped gas to bleed off before final disengagement of threads.
WARNING: FULL CYLINDER PRESSURE MAY EXIST INSIDE PRESSURE-TYPE CAP. CAP MAY BE BLOWN OFF WITH SOME FORCE IF UNSCREWED TOO RAPIDLY TO ALLOW FOR VENTING OF TRAPPED GAS.
NOTE: Pressure-type caps are used on oxygen cylinders having metal seats in the shutoff valves and are usually retained to cylinder with a short length of chain. Do not cut or detach chain after removal of cap.
N. Place fully charged cylinder assembly in mounting position.
NOTE: Ensure that high pressure outlet aligns with high pressure line connection.
O. Connect high pressure oxygen line. Tighten nut to a torque of 650 to 700 pound-inches. Connect overboard discharge line. Ensure connection is tight.
WARNING: NO OIL, LUBRICANT OR GASKETS SHALL BE USED IN MAKING THESE CONNECTIONS.
P. Clamp cylinder assembly in position.
Q. Open all oxygen cylinder shutoff valves slowly to prevent sudden pressure rise. This will minimize the possibility of fire due to resultant temperature rise. Ensure that valves are also open fully. Do not exceed 25 pound-inches (finger-tight). Then close valves one-fourth turn. Lockwire valve in this position when you restore the system to normal.
WARNING: VALVES MUST BE OPENED SLOWLY OR EXCESSIVE TEMPERATURES MAY RESULT.
CAUTION: IF GIVEN TORQUE IS EXCEEDED, VALVE MAY BE DAMAGED.
NOTE: Use the 0.020-inch diameter copper lockwire.
R. Check that no leakage exists at cylinder connections using leak test solution specified in Chapter 20. Test solution shall be wiped off with a clean cloth immediately after testing.
S. Check that system pressure is within required range.
T. If oxygen cylinders have pressure caps retained to cylinders by chains, snap cap in stowed position.
U. Restore system to normal by closing oxygen cylinder access.
5C9
May 01/99 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 12-15-21 Page 203
EFFECTIVITY
AIRPLANES WITH EXTERNAL SERVICING PANEL
3. Servicing Oxygen System (External Fill Method) (Airplanes with External Servicing Panel)
A. General (Fig. 201)
(1)
Servicing the crew oxygen systems may be accomplished by replenishing the oxygen from externally located oxygen ground servicing equipment. The oxygen servicing is accomplished at a servicing panel located on the right side of the airplane. The servicing panel filler port is approximately 6 feet above the ground and servicing is accomplished by standing on the ground. The oxygen enters through a common filler valve that controls the rate of filling and the final pressure. The following information and requirements should be reviewed and carefully considered prior to the servicing operation.
(2)
Servicing Personnel
(a) The oxygen servicing operation shall be performed by qualified personnel. The qualified person must understand the operation of the airplane oxygen servicing panel, the operation of the oxygen ground servicing equipment, and connection of ground servicing equipment to the airplane servicing panel filler port. Servicing personnel should also be alert to emergency situations during oxygen system servicing.
Oxygen System Servicing Panel 5C8
12-15-21 Figure 201 Jun 20/85
Page 204
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