CORROSION PREVENTIONMANUAL
FUSELAGE -SECTION 46
2. Corrosion Prevention
A. Following cleaning of suspected areas, a thorough inspection as described in
Volume 1, 20-20-00 is effective to ensure that protective finishes provided
during manufacture remain intact.
B. Where corrosion exists (noticeable bulges of the skin or white deposits of
corrosion products at fastener heads or joint edges), refer to the index
column in 53-00-01 for reference rework chapter.
C. For minor corrosion, to minimize the downtime of the airplane, the corrosion
products should be cleaned off, followed by the application of a corrosion
inhibiting compound into the affected area to retard the corrosion process
(Ref Volume 1, 20-60-00). The finish system should be restored at the first
opportunity consistent with the maintenance schedule.
D. Prevention Treatment
(1)At first opportunity consistent with scheduled maintenance activity,
corrosion prevention treatment should be accomplished in the external
drains and drain paths, cargo door area, and door openings.
(2)External Drains:
(a)
Clean out drains and drain paths.
(b)
Check that drain valve is free to open and close.
CAUTION: OBSERVE DRAIN VALVE TORQUE LIMITS. EXCESSIVE TIGHTENING OF
PLUNGER TYPE DRAIN VALVE WILL CAUSE VALVE FLANGE TO CRACK OR
BREAK.
(c) If required, remove plunger type drain valve from outside the fuse-lage, clean out obstructions and reinstall valve until flange con-tacts skin. Tighten to 15 lb-in. maximum.
(3)No. 2 and 3 Cargo Compartment
(a)
Remove sidewall lining and insulation blankets in the cargo compart-ment beneath the main deck entry and cargo doors to expose frame,
stringer, doubters and skin.
(b)
Remove floor liners to gain access to bilge areas, if any.
(c)
Remove ceiling lining for access to main deck floor beams and inter-costals.
(d)
Replace broken or damaged finishes. Refer to Volume 1, 20-60-00 for
protective finish systems.
(e)
Replace or repair broken or damaged leveling compounds used for
drainage.
Volume 2-757
53-60-01
Page 2
OCT 01/00
CORROSION PREVENTION MANUAL
FUSELAGE -SECTION 46
(f)
Apply water displacing corrosion inhibiting compound to all exposed
structure under the cargo floor and to the sidewalls beneath the
upper lobe entry and cargo doors. The use of spray equipment with
nozzle directed into faying surfaces is recommended. Do not apply
excessively.
(g)
Allow solvent to evaporate before reinstalling insulation blankets.
(h)
Install blankets so they are taut.
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