TASK 53-11-37-600-804
4. Galley and Lavatory Areas - Corrosion Prevention
Figure 203
A. General
(1) Areas under galleys and lavatories are susceptible to corrosion because of spillage of fluids or
food. Leakage from plumbing lines also contributes to corrosion. Seat tracks in galley or
lavatory areas are particularly susceptible because of exposure to traffic debris and spillage
which collect inside the track. Corrosion has also been reported on the forward lavatory
bulkhead-to-floor area and door post, aft of the lavatory door.
(2) Corrosion of the aluminum faced floor panels under galleys and lavatories has been alleviated
by using fiberglass faced balsa panels.
(3) Insulation blankets are provided on cabin interiors for passenger comfort and to minimize the
condensation of warm cabin air on cold skins and stringers. Corrosion has been experienced in
areas where the blankets are not installed taut and wrap around stringers or lie on the skins.
Reports of water soaked blankets have been common in these instances.
(4) Unsealed covers permit water to enter the blanket and drain. The blankets serve as drain
paths into the lower lobe drain masts. Water repellent blanket filler is used.
(5) A water dam and seal has been added to the outboard side of the forward lavatory floor, and
between the aft lavatories. Floor drains have been added to the aft lavatories and a drain
installation to the forward lavatory.
(6) For improved corrosion protection, a production change has been made to apply sealant,
A00247, class F, to inboard flanges of stringers and to portions of frames that contact
insulation blankets.
(7) Severe corrosion and corrosion cracking have been reported on the lower ten inches of the
bulkhead forward face. Corrosion of the bulkhead web can result in severe cracks and rapid
cabin depressurization. The corrosion, has been attributed to fluids from galleys and lavatories.
A plugged drain hole in the station 1016 frame chord assembly can trap these fluids and
thereby accelerate the corrosion process. See Figure 203 for aft pressure bulkhead.
(8) Apply corrosion inhibiting compound corrosion inhibiting compound, G00009 to wet areas
(doorways, galleys and lavatories) of the main cabin Ref. (Figure 203).
(9) Refer to CORROSION PREVENTION, SECTION 51-00 of this manual for a discussion of the
Aging Airplane Corrosion Prevention and Control Program and related documentation.
Structural items within this section are subject to the unique requirements of the mandatory
Corrosion Prevention and Control Program.
B. References
Reference Title
51-00 CORROSION PREVENTION
51-00-59 STANDARD PREVENTIVE MAINTENANCE PROCEDURES
SRM 737-678 Structural Repair Manual
C. Consumable Materials
Reference Description Specification
A00247 Sealant - Pressure And Environmental -
Chromate Type
BMS5-95
D00633 Grease - Aircraft General Purpose BMS3-33
G00009 Compound - Organic Corrosion Inhibiting BMS3-23
737-600/700/800/900
AIRCRAFT MAINTENANCE MANUAL
53-11-37
Page 214
D633A101-ILF Oct 15/2015
ECCN 9E991 BOEING PROPRIETARY - Copyright © Unpublished Work - See title page for details
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