757 防腐手册 CORROSION PREVENTION MANUAL(52)

1. General

A. The wing  trailing edge consists of the fixed wing trailing edge as well as
removable trailing edge airfoils such as flaps and attach/attached fit-tings. The flap tracks, links, and roller assemblies are in an exposed loca-tion and subject to corrosion. Inadequate lubrication of the moveable
components may lead to excessive wear, corrosion, and possible seizure
shortening the expected service life.

B. Delamination and damage to the trailing edge wedge of both the inboard and
out board flaps may occur. Refer to SB 757-57-0043 for inspection, repair,
and replacement.

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. Refer to Volume 1, 20-60-00 for details on
the application of corrosion inhibiting compound.

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, do
corrosion prevention treatment on the flap tracks, links and roller
assemblies of all removable trailing edge airfoils.

(2)Periodically  inspect the flap roller mechanism and lubricate the flap
rollers and bearings with MIL-G-23827 grease.

(3)
Do not apply corrosion inhibiting compounds on grease joints or sealed
bearings. These compounds dissolve grease and other lubricants. They are
penetrating compounds and can get around the seals and into the bear-ings.

E.
Frequency of Application

(1)
Periodic inspection is required to areas identified as susceptible to
corrosion and should be consistent to the schedules specified in the
Maintenance Planning Document. Operators must be aware of reported prob-lems and areas of occurrences.

(2)
Periodic application of BMS 3-23 compounds is necessary to areas identi-fied and should be consistent to the schedule specified in the Mainte-nance Planning Document.

Volume 2-757

57-50-01
Page 1 OCT 01/00
CORROSION PREVENTION MANUAL
TRAILING EDGE AND TRAILING EDGE DEVICES

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Volume 2-757