Volume 1
20-10-00
Page 8
OCT 01/01
MOVEMENT DUE TO
FUSELAGE PRESSURIZING FRETTING DUE TO WING FLEX
WING FUEL TANK ACCESS PANELS
FRETTING WITH WING MOVEMENT
Example of Fretting Corrosion
Figure 7 (Sheet 1)
Volume
20-10-001
Page 9
OCT 01/01
Example of Fretting Corrosion
Figure 7 (Sheet 2)
Volume 1
20-10-00
Page 10
OCT 01/01
Example of Microbial Corrosion
Figure 8
Volume 1
20-10-00
Page 11 OCT 01/01
Example of Galvanic Corrosion
Figure 9
Volume 1
20-10-00
Page 12
OCT 01/01
CORROSION PREVENTION MANUAL
GENERAL INFORMATION
INSPECTION AND DETECTION
1. Inspection for Corrosion
A. General
The regular maintenance program should include inspection for corrosion
followed by correct treatment of affected areas. The areas should be
inspected for not only actual corrosion damage but also for conditions that
could cause corrosion (such as damaged finishes or blockage of drain holes).
Because corrosion is a problem that will not go away, frequent inspection of
the problem areas is recommended. Unusual environmental conditions in some
geographical locations could make changes necessary to the frequency of
inspections. Refer to 20-30-00 for more details.
B. Where to look. Because all parts of the airplane can get corrosion, each of
the areas on the airplane must be examined regularly. Refer to Volume 2 for
details of possible areas of corrosion and recommended frequencies of
inspection and treatment. Here are some examples:
(1)Interior surfaces and lap joints. Be sure to include areas where drain
holes could become clogged. Fittings, braces, component parts inside the
airplane and structural shapes such as gussets, stiffener webs and mate-rial hog-outs can catch unwanted material and moisture to cause corro-sion.
(2)Exterior skin areas, painted or not. Carefully examine skin areas on the
fuselage, wing and tail. Be sure to include fastener locations and panel
edges. If you find corrosion around fastener locations, be sure to
remove the fasteners and look for corrosion under the fastener heads and
in the holes. Corrosion removal around such fasteners without fastener
removal will not stop the corrosion under the fasteners.
(3)Exposed fittings. Fittings and brackets open to wear or damage to sur-face finish can get corrosion. Such parts are in areas such as:
(a)
Horizontal stabilizer and vertical fin fittings
(b)
Engine mount fittings
(c)
Hydraulic and electrical brackets in the wheel well areas
(d)
Hydraulic and electrical brackets in the open areas of the front and
rear spars of the wing.
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