K. The wing-to-body fairing is constructed of nonmetallic sandwich material
and is attached by an aluminum frame to the fuselage. The wing-to-body fair-ing frame has a corrosion protective finish that consists of chemical finish
(alodine) on clad aluminum parts, anodize surface treatment of nonclad
parts, a coat of BMS 10-11, type I primer and BMS 10-11, type II white
enamel. All fairing structure permanently attached to the outside of the
body skin is fay sealed with BMS 5-95 sealant. The outside of the body skin
covered by the fairing is primed with BMS 10-79, type II, and a coat of BMS
10-60, type II gray enamel. Where removable fairings contact the body skin,
the body skins are coated with BMS 10-86 teflon coating. All fairing struc-ture receives BMS 3-23 after assembly and installation. Beginning with line
number 37, the surface contacted by the fairing access doors when in the
closed position is coated with BMS 10-86, type 1 teflon filled coating (Ref
53-40-05, Fig. 1).
L. Airplane, line number 707 and on; SRP 53-0052 applies BMS 3-29 Corrosion
Inhibiting Compound on top of floor beams and moisture barrier tape on top
of floor panels in all wet areas (galleys, lavatories, and doors).
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. There 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, wheel well opening, door opening and wing to body fairing.
(2)External Drains:
Volume 2-757
53-40-01
Page 2
OCT 01/00
CORROSION PREVENTION MANUAL
FUSELAGE -SECTION 44
(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 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：757 防腐手册 CORROSION PREVENTION MANUAL(32)
