01 March 2005
a. Verify installation of fasteners. Replace as
i. System Fluids. The coolant of high power radar
produces a black substance called "black plague" that
adheres to immersed metal surfaces and adversely
b. Inspect form-in-place gasket. Repair or replace
affects heat transfer properties. Waveguides are
as required in accordance with the applicable structural
susceptible to this black plague.
j. Corrosion Effects of Solder Flux. Solder flux
c. Verify water drains are open and clear.
residues may be conductive as well as corrosive. They
are often "tacky", collecting dust which can absorb
d. Prepare compartment with "witness material"
moisture and create current leakage paths. Solder flux
such as blotter paper, paper towels, etc. The "witness
resin appears as an amber-colored globule, drip, or
material" shall be placed in a manner that will indicate
tail, at or near, the solder joint. Ultraviolet light may be
a leakage path during the water test.
used to detect the flux resin residue. Under the
Ultraviolet light, traces of flux appear as a fluorescent
e. Secure compartment doors.
yellow to light brown residue.
f. Where fresh water is in adequate supply, apply
water with a hose to the exterior surface for
approximately 5 minutes. Where water is in short
Specific inspection criteria for individual types
supply, slowly pour a bucket of fresh water over the
of avionic subsystems, equipment, and
g. Allow 3 to 5 minutes for water to drain.
3-2.3. GENERAL INSPECTION PROCEDURE. The
following general procedures shall be used for avionic
h. Open compartment doors and examine "witness
material" for signs of water.
a. Clean area or component by wiping with cleaning
cloth, CCC-C-46, Class 7 (Vol IV or V, Chapter 2) to
remove interfering soil or contaminant.
Adhesive/Sealant, Silicone RTV,
b. Use a 10X magnifying glass (Vol IV or V, Chapter
3) to inspect for evidence of corrosion and determine
extent of damage. In the case of miniature or
microminiature circuit boards and components, use
the appropriate microscope, as necessary.
Sealing and Coating Compound
c. Refer to the applicable service directives for
3-2.4. WATER INTRUSION INSPECTION. The
i. If leaks are observed, they shall be sealed with
avionic technician should routinely inspect the interior
MIL-A-46146 or MIL-PRF-81733 (Vol IV or V, Chapter
of equipment bays for evidence of water intrusion. Any
2). MIL-PRF-81733 shall be used when sealant will be
evidence of corrosion damage should be reported so
in contact with fluids such as coolants, fuel, or hydraulic
that appropriate maintenance action can be scheduled.
To determine and eliminate the source of water