NAVAIR 01-1A-509-3
01 March 2005
TM 1-1500-344-23-3
TO 1-1-689-3
be maintained, because there is, currently, no known
method of preserving the internal surfaces of a
waveguide without adversely affecting the electrical
Compound, Corrosion Preventive
3
characteristics, except by plating the surfaces with
Water Displacing
another metal, such as gold or silver, in production.
MIL-C-81309
This process is very expensive and seldom applied to
waveguide sections used in aircraft. The integrity of a
h. Preserve all exposed areas and hardware with a
waveguide system is degraded every time a waveguide
spray coating of Water Displacing Corrosion Preventive
seal is broken for maintenance. Waveguides that must
Compound, MIL-C-81309 Type II (Volume IV or V,
be opened for maintenance shall be sealed at the ends
Chapter 2). Connecting surfaces shall be coated with
(flanges) with the appropriate protective cap or with
Water Displacing, Corrosion Preventive Compound,
Pressure Sensitive Tape, SAE AMS-T-22085 Type II
MIL-C-81309 Type III (Volume IV or V, Chapter 2).
(Volume IV or V, Chapter 2). It is important that all
residues from the pressure sensitive tape are removed
6-3.4. WAVEGUIDE FEED HORNS. Waveguide feed
from all mating flange surfaces prior to reassembly of
horns, attached to some antenna dishes, are subject
the waveguide. Remove corrosion, clean, and preserve
to corrosion attack at the open end of the waveguide.
external surfaces of waveguides as follows:
To protect this open-end area from corrosion, perform
the following:
a. Ensure ends of waveguides are sealed as
described above.
b. Remove external corrosion with Abrasive Mat,
Alcohol, Isopropyl
6
A-A-58054 Type I (Volume IV or V, Chapter 2). Scrub
TT-I-735
affected areas until all corrosion and contaminants are
loosened.
a. Clean with a Cleaning Cloth, CCC-C-46 Class 7
(Volume IV or V, Chapter 2), dampened with Isopropyl
Alcohol, TT-I-735 (Volume IV or V, Chapter 2).
Alcohol, Isopropyl
6
b. Allow to air dry.
TT-I-735
c. Using a Cleaning Cloth, CCC-C-46 Class 7
(Volume IV or V, Chapter 2), dampened with Isopropyl
Compound, Corrosion Preventive
3
Alcohol, TT-I-735 (Volume IV or V, Chapter 2), wipe
Water-Displacing
the affected areas clean.
MIL-C-81309
d. Remove seals that had been applied to ends of
c. Spray the outer throat area of waveguide opening
waveguides.
with an ultra-thin coat of Water Displacing, Corrosion
P r e v e n t i v e Compound, MIL-C-81309 Type III
e. With a clean Cleaning Cloth, CCC-C-46 Class 7,
(Volume IV or V, Chapter 2). Direct the spray across
dampened with Isopropyl Alcohol, TT-I-735 (Volume IV
the throat so that it hits the opposite side and does not
or V, Chapter 2), clean the mating flange surfaces,
enter the waveguide past the flared throat area.
being especially careful to ensure all tape residue is
removed.
6-3.5. LIGHTING SYSTEMS AND ASSEMBLIES.
External formation lights, wing tip lights, rotating
f. Allow to air dry.
beacons, and lower fuselage anti-collision lights are
highly susceptible to corrosion. This can be due to
g. Reconnect all waveguides and plumbing.
poor seals, exposure to the elements in flight, or water
intrusion. In most cases corrosion is heaviest at the
base of the bulb because of dissimilar metal contact
between the bulb and socket. Treat corrosion as follows:
6-25