3. Repeat procedure for each tank.
4. When all tanks are flushed, clean all filters.
CONDITIONS AFFECTING CORROSION
Some conditions affecting corrosion are:
l. Heat and humidity.
2. Different metals and their relative sizes.
3. Frequent contributing factors to corrosion:
a. Soil and atmosphere dust.
b. Oil, grease and exhaust residues.
c. Salt water and salt moisture condensation.
d. Spilled battery acids and caustic cleaning solution.
e. Welding, brazing and soldering flux residue.
A clean aircraft will resist corrosion better than a dirty one. Cleaning frequency depends on geographical
location, type of operation, etc. Remove soil as soon as possible, especially when on a high temperature area.
After cleaning, ensure that no cleaning solution remains in holes, crevices, or joints that may lead to
increased corrosion. All exposed areas (landing gear, flap tracks, control surface, hinge parts, etc.) must be
lubricated after cleaning.
INSPECTION
Check for corrosion at every inspection. In trouble areas, inspection frequency must be increased.
In addition to routine inspections:
l. Aircraft operating around a marine environment must be given special inspections on a weekly basis.
2. Aircraft operating in semi-acid conditions must be inspected monthly. Semi-acid conditions are likely
to occur in industrialized areas. Sulphur-bearing particles in dust, smoke, and smog attack painted
surfaces.
3. Inspection for corrosion must be performed by personnel familiar with corrosive problems and
remedies.
a. Daily and preflight inspection must include engine frontal areas, all intake vents, engine
compartments, gaps, seams, faying surfaces in exterior skins, wheel and wheel well areas, battery
compartment, fuel cell and all other drains, and any bilge areas not requiring extensive removal of
inspection access covers.
b. Detailed inspection must include above referenced areas along with areas requiring removal of
inspection plates and panels to thoroughly inspect internal cavities of aircraft.
4. Paint tends to hide corrosion in its initial stages. However, the results of corrosion can sometimes be
seen as blisters, flakes, chips, and other irregularities in paint.
CORROSION REMOVAL AND CONTROL
Corrosion cannot be prevented or eliminated on aircraft; it can only be reduced to an acceptable level by
proper control methods.
All corrosion products must be removed prior to refinishing. If not removed, corrosion will begin again,
even though affected area is refinished.
20 - 24 - 00
Page - 20 - 11
Reissued: August 1, 1986
1E14
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
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