01 March 2005
2-5.3.1. General. Contamination is responsible for
a. Cleaning solvents or materials can be trapped in
corrosion problems in avionic equipment. Cleaning
crevices or seams. This may interfere with later
can prevent many of these problems and is the first
applications of protective coatings as well as causing
logical step following inspection. Cleanliness is very
important in maintaining the functional integrity and
b. Vigorous or prolonged scrubbing of laminated
conductive or insulating. As a conductor, it may provide
circuit boards can cause damage to the boards.
undesired electrical paths, while as an insulator it may
interfere with proper operation.
c. Certain cleaning solvents soften conformal
coatings, wire coverings, acrylic panels, and some
2-5.3.2. Cleaning Methods Selection Criteria. The
selection of the cleaning method is a decision to be
made by the work center supervisor or equipment
2-5.3.4. When to Clean. The immediate removal of
operator. Certain circuit components can be damaged
corrosion on avionic equipment and surrounding
by support equipment. This paragraph is intended to
structure is always a high priority in corrosion control.
emphasize the limitations involved in using support
Therefore, immediate cleaning shall be accomplished
e q u i p m e n t on certain avionic equipment and
after avionic equipment has been exposed to any of
components. The method used shall be based on:
the following conditions:
a. Adverse weather conditions or salt-water spray
(open canopy, equipment door, or panel).
Always select the mildest method of cleaning
that will accomplish the task.
b. Fire-extinguishing agents.
c. Spilled electrolyte or corrosion deposits around
battery terminals and the general vicinity of the battery
d. Corrosion removal or component repair.
c. Type of avionic equipment.
2-5.3.5. Precleaning Treatment.
a. Disconnect power supply.
b. Ensure drain holes are open.
Acid cleaners shall not be used on avionic
c. Remove covers or panels.
d. Disassemble where practical.
Deionized or distilled water is required in
e. Use only authorized materials.
some conformal coating applications. If
f. Ensure compatibility of materials prior to use.
deionized or distilled water is not available
locally, distilled water may be procured under
g. Mask and protect accessories or components to
the stock number listed in Volume IV or V,
prevent entrance of water, solvents or cleaning
2-5.3.3. Hazards of Cleaning. It is a good maintenance
practice to use the mildest cleaning method that will
2-5.3.6. Cleaning and Drying Restrictions. Certain
ensure proper decontamination. It is also important
circuit components create potential problems during
that the correct cleaning solution and cleaning materials
cleaning and drying. In most cases, the problems can
are used to avoid damaging avionic equipment and
be overcome prior to cleaning the equipment. The
components. The following emphasizes some of the
greatest potential for problems is the circuit component
hazards of cleaning: