(a)
213 Forward Cargo Compartment
(b)
214 Mix Manifold Bay
(c)
215 Aft Cargo Compartment
(2)
Access Panels
(a)
4404R, Forward Cargo Door
(b)
4504R, Aft Cargo Door
D. Prepare for Cleaning
(1)
Open this circuit breaker and attach a DO-NOT-CLOSE tag:
(a) Circuit Breaker Panel P6 or P18:
1) CARGO FIRE EXT 1
(2)
Open 4404R Forward Cargo Door, or 4504R Aft Cargo Door.
(3)
Gain access to the discharge nozzles in the forward or aft cargo compartment.
(4)
Remove the lining at the aft end of the forward cargo compartment, to gain access to the cargo fire bottle (AMM 25-52-131/401).
(5)
If required, remove the air conditioning duct in front of the cargo fire bottle (AMM 21-21-11/401).
(6)
Disconnect the appropriate discharge tube from the cargo fire bottle discharge head.
(7)
Remove discharge nozzles from the discharge tubing in the applicable cargo bay (Fig. 701).
(a)
Remove four screws securing pan cover retainer to ceiling bracket.
(b)
Remove cargo compartment ceiling panel as required to gain access to discharge tubing connection (AMM 25-52-111/401).
(c)
Remove the two discharge nozzle screws. Retain discharge nozzle spacer, pan cover assembly, pan cover spacer and discharge nozzle.
(d)
Remove lockwire and discharge nozzle from discharge tube.
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E. Procedure
(1)
Ensure discharge nozzle is free of unwanted debris.
(2)
Connect air pressure source to selected cargo fire bottle discharge tube.
(a) Ensure air is flowing from all discharge nozzles in the selected cargo compartment.
(3)
Remove the pressure source from the selected cargo fire bottle discharge tube.
F. Return Airplane to its Normal Condition
(1)
Connect discharge tubing to discharge head on cargo fire bottle.
(a)
Apply a layer of BMS3-27 compound to outlet threads, outlet end, and outlet inner diameter where tube assembly attaches to discharge head.
(b)
Connect tube assembly to discharge head.
NOTE: Yellow indicates the plumbing that supplies halon to the forward cargo compartment. Blue indicates the plumbing that supplies halon to the aft cargo compartment.
(c)
Remove any excess BMS3-27 compound.
(d)
Tighten discharge tubes to 266-294 pound-inches for the FWD (1/2 inch) connector and 342-378 pound-inches for the AFT (5/8 inch) connector.
(2)
If removed, install air conditioning duct in front of cargo fire bottle (AMM 21-21-11/401).
(3)
Install lining at the aft end of forward cargo compartment (AMM 25-52-131/401).
(4)
Install discharge nozzles on the discharge tubes.
(a)
Install discharge nozzle, spacers and pan cover assembly on discharge tube and hand tighten.
NOTE: Ensure pan cover assembly holes and pan cover spacer line up with those in ceiling bracket. Ensure holes in discharge nozzle and discharge nozzle spacer line up with those in pan cover assembly.
(b)
Torque discharge tube nut to 45-55 pound-feet, and install lockwire.
(c)
Secure discharge nozzle to pan cover assembly with two mounting screws.
(d)
Align pan cover spacer and retainer, secure with four mounting screws.
(e)
Install cargo compartment ceiling panel (AMM 25-52-111/401).
(f)
If removed, install air conditioning duct in front of cargo fire bottle (AMM 21-21-11/401).
(5)
Close this circuit breaker and remove DO-NO-CLOSE tag:
(a) Circuit Breaker Panel P6 or P18:
1) CARGO FIRE EXT 1
(6)
Close 4404R, Forward Cargo Door, or 4504R, Aft Cargo Door.
550
26-25-0 Page 702 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. May 01/99
K13406
550 Cargo Bay Fire Extinguishing System Tubing Cleaning
May 01/99 Figure 701 26-25-0
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