(2)
One to two crew oxygen cylinder - wire change
B. A small change to the electrical wires is necessary on the voltage averaging unit. This is necessary when you change from two to one or from one to two crew oxygen cylinders. This will make sure the correct system pressure will show on the EICAS status page.
C. The voltage averaging unit is installed in the ceiling beam on the right side of the forward cargo compartment. More specifically it is also aft of the cargo door at approximately Sta 720. Access is through the access panels in front of the passenger oxygen cylinders which is attached by snaps and velcro tape.
TASK 35-11-00-862-001
2. Two to One Crew Oxygen Cylinder - Wire Change_____________________________________________
A. References
(1)
24-22-00/201, Manual Control
(2)
35-00-00/201, Oxygen
(3)
35-11-00/501, Crew Oxygen System
(4)
IPC 35-11-12 Fig. 1
(5)
SSM 35-11-01
(6)
WDM 35-11-13
B. Access
(1) Location Zone 124 Forward Cargo Container Compartment, Aft Half Right
C. Procedure
S 912-023
(1)
Read and obey the safety precautions and general instructions before you do the maintenance (Ref 35-00-00/201).
S 862-002
(2)
Open this circuit breaker and attach a DO-NOT-CLOSE tag:
(a) P7 Overhead Circuit Breaker Panel
1) 7D4 OXYGEN VALVE & IND
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
S 012-003
(3)
Open the access panels to the passenger oxygen cylinders which are attached by snaps and velcro tape.
S 032-004
(4)
Disconnect the electrical connector DM992 from the voltage averaging unit,M992 for the crew oxygen system.
S 862-005
(5)
Cut, seal with a cap and, keep the jumper wire (P/N W1092-106-22) on the electrical connector which connects pins 11 and 12.
NOTE: The crew oxygen pressure on the EICAS status page will show
____ one-half the correct system pressure if the jumper is not cut.
S 432-006
(6)
Connect the electrical connector on the voltage averaging unit and install a safety wire.
S 862-007
(7)
Supply the electrical power (Ref 24-22-00/201).
S 862-008
(8)
Remove the DO-NOT-CLOSE tag and close this circuit breaker:
(a) P7 Overhead Circuit Breaker Panel
1) 7D4 OXYGEN VALVE & IND
S 782-009
(9) Do the task: "Crew Oxygen Pressure Indication Test" (Ref 35-11-00/501).
NOTE: This will make sure the pressure for the crew oxygen system
____
is shown on the EICAS status page.
S 412-010
(10)
Close the access panels to the passenger oxygen cylinders which are attached by snaps and velcro tape.
S 862-011
(11)
Remove the electrical power if it is not necessary (Ref 24-22-00/201).
TASK 35-11-00-862-012
3. One to Two Crew Oxygen Cylinder - Wire Change
_____________________________________________
A. References
(1) 24-22-00/201, Manual Control
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35-11-00
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
(2)
35-00-00/201, Oxygen
(3)
35-11-00/501, Crew Oxygen System
(4)
35-11-12/401, Voltage Averaging Unit
(5) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 氧气 OXYGEN(15)
