Par 1006 Page 189 Exposed areas such as terminal posts, toggles, push buttons, or rotary switches should be cleaned and preserved as follows:
(1) Remove contamination with fresh water while scrubbing with an acid brush.
Thoroughly rinse with fresh water.
(2) Blow off excess liquid from component with not more than 10 psi dry air pressure or dry nitrogen. Wipe with a clean cloth to help reduce drying time.
(3) Use Dry Cleaning Solvent, MIL-PRF-680, Type II, applied with an acid brush, to remove stubborn oil and grease stains and clean sliding contacts, contact points, and circuit breaker points. Rinse with Dry Cleaning Solvent, MIL-PRF-680, Type II. Ensure removal of any contamination from sliding contacts, contact points, and circuit breaker points. Wipe with a clean cloth.
(4) Dry in accordance with one of the methods described in subparagraph 1005b. Do not apply Water-Displacing Corrosion Preventive Compounds as directed in that paragraph.
(5) If required, preserve exterior of switch in accordance with Chapter 4, paragraph 407.
g. Antennas. Antennas should be cleaned and preserved as follows:
(1) Remove the antenna in accordance with OEM maintenance instructions.
(2) Visually examine antennas, insulators, and electrical connectors for damage. Repair or replace as required.
(3) Brush or spray a mixture of one part Aircraft Cleaning Compound conforming to MIL-PRF-85570, Type I, to nine parts of fresh water. Clean surfaces with a clean cloth dampened with cleaning solution.
(4) Rinse with clean fresh water. Wipe excess water with a dry, clean cloth.
(5) Preserve antenna in accordance with Chapter 4, paragraph 407.
h. Mounting Racks and Shock Mounts. Mounting racks and shock mounts should be cleaned and preserved as follows:
(1) Remove the mounting racks, shock mounts, and associated hardware in accordance with the OEM maintenance instructions.
(2) Clean the detailed parts or components in accordance with subparagraph 1004b.
(3) Dry the mounting racks, shock mounts, and associated hardware in accordance with one of the methods described in subparagraph 1005b.
Par 1006 Page 190
(4) Tag the equipment to be forwarded to the avionics repair station. The tag should indicate date, cleaning and drying method, and preservation type applied. Include any additional notes that may be helpful.
i. Non-removable Avionics Equipment. Non-removable avionics equipment exposed to saltwater or fire extinguishing agents should be cleaned and preserved as follows:
(1) Ensure aircraft or equipment is electrically grounded.
WARNING: Ensure that all electrical power sources, including batteries, are disconnected from the aircraft or equipment and all other powered systems (hydraulic, pneumatic, and mechanical) are deactivated.
(2) Ensure all external electrical power and batteries are disconnected. Remove hydraulic and pneumatic power and install safety struts in hydraulic, pneumatic, and mechanic actuated devices.
(3) Open all equipment bay doors.
(4) After all removable components have been removed in accordance with the OEM maintenance instructions and in the order determined by the priority established in the emergency reclamation list or Table 10-1, examine all non-removable components for evidence of saltwater, fire extinguishing agents, smoke, oily films, etc.
(5) Contaminated items should be cleaned in accordance with subparagraph 1004b whenever possible. Ensure that areas behind and under mounting structure and components are thoroughly cleaned. When the primary cleaning method cannot be accomplished, use one of the alternate cleaning methods described in subparagraph 1004c.
(6) For all non-removable avionics components and electrical connectors, dry and preserve in accordance with subparagraph 1006k.
j. In-place Cleaning. Where access is limited, use a backpack hand pump for one of the cleaning methods described in subparagraph 1004c, except the solvent method described in subparagraph 1004c(1). Dry and preserve limited-access components in accordance with subparagraph 1006k.
k. Drying and Preservation of Non-removable Avionics Equipment. Dry and preserve non-removable avionics components as follows:
(1) Blow off excess liquid from component with not more than 10 psi dry air pressure or dry nitrogen. Deflect the jet of air off interior, back, and sides of enclosure to diffuse.
(2) Where authorized, dry the equipment with a hot air gun. Where the hot air gun is not authorized, wipe the area with a dry, clean cloth and allow to air dry.
Par 1006 Page 191
(3) For all avionics components and electrical connectors, apply (by spraying) a coat of Water-Displacing Corrosion Preventive Compound, Ultra-Thin Film, conforming to MIL-PRF-81309, Type III. Wipe off excess preservative with a dry, clean cloth.
l. Terminal Boards, Junction Boxes, Relay Boxes, and Circuit Breaker Panels.
Terminal boards, junction boxes, relay boxes, and circuit breaker panels not normally removed from the aircraft or equipment should be cleaned as follows:
(1) Ensure aircraft or equipment is electrically grounded.
WARNING: Ensure that all electrical power sources, including batteries, are disconnected from the aircraft or equipment and all other powered systems (hydraulic, pneumatic, and mechanical) are deactivated.
(2) Ensure all external electrical power and batteries are disconnected. Remove hydraulic and pneumatic power, and install safety struts in hydraulic, pneumatic, and mechanic actuated devices.
(3) Remove covers and access panels.
(4) Examine all components for evidence of saltwater, fire extinguishing agents, smoke, oily films, etc.
(5) Contaminated components should be cleaned in accordance with the primary cleaning method described in subparagraph 1004b whenever possible. Ensure that all areas behind and under mounting structure and components are thoroughly cleaned. When the primary cleaning method cannot be accomplished, use one of the alternate cleaning methods described in subparagraph 1004c.
(6) For all non-removable avionics components and electrical connectors, dry and preserve in accordance with subparagraph 1006k.
m. Electrical Connectors and Receptacles. Electrical connectors and receptacles require special procedures for cleaning and preserving. Connectors and receptacles that cannot be opened and separated for cleaning should be cleaned, inspected, and preserved in place as follows:
(1) Disconnect and disassemble connector and receptacles to the extent possible to release entrapped contaminants.
(2) Thoroughly rinse connector and receptacles with fresh water.
(3) Blow off excess liquid from connector and receptacles with not more than 10 psi dry air pressure or dry nitrogen. Wipe with a clean cloth to help reduce drying time.
(4) To remove stubborn oil and grease contaminants, use Dry Cleaning Solvent, MIL-PRF-680, Type II, applied with an acid brush, followed by wiping with a solvent-dampened cleaning cloth.
Par 1006 Page 192
(5) Apply (by spraying) a light coating of Water-Displacing Corrosion Preventive Compound, Ultra-Thin Film, conforming to MIL-PRF-81309, Type III, to remove any trapped liquid. Wipe off excess preservative with a dry, clean cloth.
(6) Dry and preserve in accordance with one of the methods described in subparagraphs 1005b(1) through (5). Whenever these drying methods are not applicable, allow connector to air dry.
n. Wire Harnesses and Cables. Wire harnesses and cables exposed to saltwater, fire extinguishing agents, smoke, etc., should be cleaned and preserved as follows:
(1) Remove cable clamps, straps, hangers, wire ties, etc., to allow wire harness and cable wiring to be separated.
(2) Separate wiring, open and separate connectors. Rinse with fresh water to wash away entrapped contaminants. If the wire harness, cables, or connectors are encased, the exteriors should be rinsed with fresh water.
(3) Blow excess water from wiring and connectors with not more than 10 psi dry air pressure or dry nitrogen. Wipe with a clean cloth to help reduce drying time.
(4) Wire harnesses and cables that can be readily removed from the aircraft or equipment should be dried by one of the methods in subparagraph 1005b.
(5) Wire harnesses and cables that cannot be readily removed from the aircraft or equipment should be dried using a hot air gun.
(6) Apply (by spraying) to metal components a light coating of Water-Displacing Corrosion Preventive Compound, Ultra-Thin Film, conforming to MIL-PRF-81309, Type III.
1007. AVIONICS REPAIR STATION EMERGENCY CLEANING PROCEDURES.
a. General. The initial emergency salvage and reclamation steps taken by the operator or unit level are designed to prevent further corrosion damage. Immediate induction of avionics equipment into an avionics repair station for cleaning, drying, inspection, preservation, repair, and functional testing after an accident can be delayed for many reasons. These can include the delayed access due to an ongoing accident investigation, field disassembly problems, shipping distance, and work contracts. It is, therefore, essential that the avionics repair station be ready to provide services when the equipment does arrive.
b. Emergency Reclamation Team. Each avionics repair station that operates, stores, maintains, or repairs avionics equipment should have a team identified to handle emergency reclamation situations. The team should be composed of a team leader and the necessary number of avionics technicians required to accomplish the assigned task. The primary goal of the emergency reclamation team is to accomplish those tasks that are necessary to salvage the affected equipment and perform appropriate corrosion control efforts to minimize damage and, where possible, return the equipment to usable service. Repairable equipment damaged beyond the capability of the avionics repair station may be returned to the OEM for disposition.
Par 1007 Page 193 NOTE: Units or components that will be returned to the OEM for cleaning, inspection, and repair should be tagged to indicate date of cleaning, cleaning method and materials used, and type of preservation applied.
c. Initial Screening Procedure. Avionics equipment that is damaged beyond the capability of the operator or operating unit to clean, inspect, repair, test, and preserve will normally be forwarded to an avionics repair station for disposition. Upon receipt, the avionics repair station should screen the affected equipment and records to determine the following:
(1) Extent of damage (reported or observed),
(2) Local repair capability,
(3) Cleaning methods used at operator/unit activity,
(4) Drying methods used at operator/unit activity, and
(5) Preservation methods used at operator/unit activity.
d. Cleaning Priority. After initial screening, the cleaning priority needs to be established by the emergency reclamation team leader. Table 10-1 will aid in determining the cleaning priority.
e. Disassembly Inspection Procedures. The extent of damage from saltwater, fire extinguishing agents, smoke, fire, heat, etc., must be determined. Most avionics equipment contains dissimilar metals and particular attention should be given to those dissimilar metal couples. Avionics equipment exposed to saltwater, fire extinguishing agents, smoke, fire, heat, etc., should be cleaned, disassembled, and visually examined as follows:
(1) Remove Corrosion Preventive Compounds, dirt, and grime with Dry Cleaning Solvent, MIL-PRF-680, Type II, to facilitate inspection.
(2) Remove all covers, access panels, modules, and normally removed components.
(3) Visually examine the individual items thoroughly for evidence of saltwater intrusion, fire extinguishing agents, smoke, fire, heat damage, etc.
(4) Visually examine the individual items for evidence of corrosion. Particular attention should be focused on areas of dissimilar metal couples.
(5) Visually examine encapsulated and conformal-coated laminated circuit boards for damage caused by saltwater intrusion, fire extinguishing agents, and cleaning solvents. Pay particular attention to conformal coatings and circuit board laminates that are discolored, softened, or deformed.
(6) Visually examine electrical cables, wires, and harnesses for signs of damage and deterioration from cleaning solvents. Pay particular attention to any signs of discoloration, softening, or cracked wire coating.
Par 1007 Page 194
(7) Disassemble and inspect electrical connectors and receptacles for damage and signs of corrosion. Pay particular attention to seals and gaskets.
(8) Visually examine hermetically sealed components for signs of broken seals and corrosion damage. Units with broken seals should be disassembled for further inspection or forwarded to the OEM for disposition.
(9) Visually examine electrical motors, generators, inverters, miniature synchro transmitters, and receivers for damage. Pay particular attention to lubricated fittings and sealed bearings.
(10) Visually examine control boxes and instruments for damage and corrosion. Pay particular attention to areas around switch toggles and knobs, hardware, interior components, and under faceplates, rubber boots, and mounting areas.
(11) Visually examine component identification and modification plates for evidence of corrosion. Pay particular attention to the condition of the fillet seal around the periphery of the plates.
(12) Visually examine shock mounts, mounting racks, cases, chassis, and cover plates for corrosion. Pay particular attention to evidence of buckling and heat damage. Check painted surfaces for cracks, nicks, and peeling. Pay particular attention to the condition of rubber shock mounts.
f. Undamaged Items. Avionics components that show no visual signs of damage should be functionally checked in accordance with the OEM maintenance instructions. The avionics component may be returned to the operator level in accordance with established procedures.
g. Damaged Items. Avionics components that show signs of damage should be repaired and functionally checked per the OEM maintenance instructions in accordance with established procedures.
h. Emergency Cleaning and Preservation Procedures. Cleaning and preservation procedures are as follows:
(1) Avionics equipment exposed to saltwater, fire extinguishing agents, smoke, fire, heat, field-applied cleaning solutions, etc., and cleaned and decontaminated at the operator or unit level should be inspected for damage in accordance with subparagraph 1007e. Corrosion removal, treatment, restoration of protective finishes, and preservation should be in accordance with Chapters 4 and 5.
(2) Avionics equipment exposed to saltwater, fire extinguishing agents, smoke, fire, heat, etc., that were not cleaned and decontaminated at the operator or unit level should be cleaned, inspected, repaired, and preserved as follows:
(a) Clean using the primary cleaning method detailed in subparagraph 1004b.
Par 1007 Page 195
(b) Inspect for damage in accordance with subparagraph 1007e, and the OEM maintenance instructions.
(c) Disposition in accordance with established procedures and the OEM maintenance instructions.
(d) Preserve in accordance with Chapter 4, paragraph 407.
(3) Avionics equipment that requires disposition and repair by the OEM should be cleaned, dried, preserved, and tagged in accordance with paragraphs 1004b, 1005, and 1006a(9).
1008. through 1100. RESERVED.
Appendix 1 APPENDIX 1. CONSUMABLE SUPPLIES AND MATERIALS
1-1. INTRODUCTION.
This appendix lists many of the acceptable type consumable supplies and materials available for avionics corrosion control.
1-2. SCOPE.
Table 1-1 provides consumable supplies and materials used for avionics cleaning and corrosion control. The table contains the product nomenclature/specification, application, and manufacturer’s designation. Items in this table are located by function in the following groupings:
Grouping Page(s)
a. Abrasives2
b. Cleaning compounds, solvents, and thinners3-4
c. Corrosion preventive compounds4
d. Lubricating oils and greases4-5
e. Cleaning cloth5-6
f. Sealants6
g. Potting compounds6-7
h. Masking materials and tapes7
i. Conformal coatings7-8
j. Neutralizing agents8
k. Chemical conversion coatings8
l. Paint, primers, and strippers8-9
m. Packaging materials9-10
n. Tracers10
Appendix 1 TABLE 1-1. AVIONICS CLEANING AND CORROSION REMOVAL CONSUMABLE
MATERIALS ITEM NO.
NOMENCLATURE/PRODUCT
SPECIFICATION
APPLICATION
ABRASIVES
1. Abrasive Mat. Aluminum Oxide Abrasive, A-A-58054, Grade A, Class 1 (Very Fine), or A-A-58054, Grade B, Class 1 (Fine) Removal of dirt and corrosion products from external avionics chassis, covers, mountings, hardware, antennas, electrical connector shells, etc.
2. Cleaning and Polishing Pad, Nonabrasive Removal of dirt and contaminants from internal avionics structures, laminated circuit boards, wave-guides, TR tubes, cavities, circuit components, relay contacts, control box face plates, etc.
3. Cloth, Abrasive Aluminum Oxide A-A-1048, 320-Grit, Type 1, Class 1 Removal of heavy corrosion products from steel, iron, aluminum, and magnesium structures, mountings, racks, chassis, covers, etc. Scuff sanding of avionics boxes prior to painting, etc.
CAUTION: Do not use Silicon Carbide Abrasive Cloth, A-A-1048.
4. Eraser, Magic Rub, Plastic, A-A-132-14, 2-1/4 x 7/8 x 7/16", (Block Shape, Beveled Ends) Removal of light tarnish on silver. Removal of light corrosion on copper, zinc, nickel, etc. For brightening of gold.
CAUTION: Use only on components that are sufficiently rigid to resist rubbing motion.
5. Eraser, Ruby Red A-A-132-3, 2-3/4 x 3/4 x 1/4 inch, (Rectangular Shape, Beveled Ends) Removal of light tarnish on silver. Removal of medium corrosion on copper, zinc, nickel, etc. For brightening of gold.
CAUTION: Use only on components that are sufficiently rigid to resist rubbing motion.
6. Eraser, Wood or Paper Encased, A-A-132-13, 6 inch x 3/16 inch diameter, (Pencil Shape) Removal of medium tarnish and corrosion products in tight areas.
CAUTION: Care should be taken not to remove thinly plated surfaces.
7. Eraser, Typewriter A-A-132-9, 7 inch x 3/16 inch diameter, (Pencil Shape) Removal of heavy tarnish on silver. Removal of heavy corrosion on copper, zinc, nickel, etc.
CAUTION: Care should be taken not to remove thinly plated surfaces.
Appendix 1 ITEM NO.
NOMENCLATURE/PRODUCT
SPECIFICATION
APPLICATION
CLEANING COMPOUNDS, SOLVENTS, AND THINNERS CAUTION: Cleaning solvents may react with coatings and circuit components. When in doubt as to the reaction, test the affected area prior to wholesale application of solvent.
NOTE: Local air pollution regulations may restrict the use of the listed solvents. Comply with all local air pollution regulations.
8. Detergent, Liquid Nonionic, MIL-D-16791, Type I For cleaning and polishing transparent plastic and glass.
Note: Mix per manufacturer’s instructions or not more than 1 oz. per gal. of water. Also used for detergent in aqueous ultrasonic cleaners and aqueous spray cleaning booths.
9. Cleaning Compound, MIL-PRF-85570, Type II General cleaning. For removal of soil and fire extinguishing chemicals. Excellent cleaner for light oils and hydraulic fluids.
10. Cleaning Compound, Solvent, Trichlorotrifluoroethane, MIL-C-81302, Type II For use only in vapor degreasers.
11. Cleaning Compound, Solvent Trichlorotrifluoroethane, MIL-C-81302, Type I (Ultra-clean) For use only in vapor degreasers.
12. Dry Cleaning Solvent, MIL-PRF-680, Type II For general purpose cleaning of structural hardware, cases, covers, mountings, etc. For removal of heavy dirt, smoke damage, contaminants, fire extinguishing chemicals, and water-displacing preservatives.
WARNING: MIL-PRF-680, Type I has a lower flash point of 100 °F (38 °C) and is not authorized for avionics cleaning.
13. Naphtha, Aliphatic, TT-N-95B, Type II For removal of polychlorinated biphenyl and silicone contaminants.
WARNING: Aliphatic Naphtha has a flash point of
60.8 °F (16 °C).
14. Isopropyl Alcohol, TT-I-735 For removal of fungus and bacteria. For removal of Van Waters and solder flux residue. For removal of contaminants on microminiature circuit components.
For general cleaning and removal of salt residue and contaminants from circuit components.
WARNING: Isopropyl Alcohol has a flash point of 53 °F (12 °C).
15. Spray Cleaning Lubricating Compound, MIL-PRF-29608, Type I Cleaner and lubricant for use on small switches and potentiometers where a residual lubricant is required after cleaning. Contains 5% silicone.
Appendix 1 ITEM NO.
NOMENCLATURE/PRODUCT
SPECIFICATION
APPLICATION
16. Thinner, Acrylic Nitrocellulose Lacquer, MIL-T-19544 Thinner for Lacquer, Acrylic Nitrocellulose MIL-L-19538C, MIL-C-22750, epoxy topcoats, Item No. 59 and 60, and MIL-P-23377 primer, Item No. 58.
17. Thinner, Paint, Petroleum Spirits TT-T-291, Type III Removal of preservative compounds.
CAUTION: Do not use on lacquers or synthetic resin base enamels.
18. Thinner, Synthetic Resin, Enamels A-A-3007 Used for thinning varnish, MIL-V-173C, Item No. 51.
CAUTION: Do not use in lacquers.
19. Thinner, Aliphatic Polyurethane Coating, MIL-T-81772, Type I (Polyurethane) Type II (Epoxy) Type III (Lacquer) For thinning urethane and polyurethane topcoats, MIL-C-83286B, and MIL-PRF-85285, Item No. 61 and 63; epoxy polyamide coatings, MIL-C-22750, Item No. 60; acrylic nitrocellulose lacquers, MIL-L-19538C, Item No. 59; and primer, MIL-P-23377, Item No. 58.
CORROSION PREVENTIVE COMPOUNDS (PRESERVATIVE)
WARNING: Do not use Corrosion Preventive Compounds around oxygen, oxygen fittings, or oxygen regulators, since fire or explosion may result.
20. Corrosion Preventive Compound, Water-Displacing, Ultra-Thin Film, Avionics Grade, MIL-PRF-81309, Type III, Class 2 (Aerosol) For use on highly critical electrical connectors’ metal surfaces. For use in interior areas. Not intended for exterior areas exposed to the elements.
21. Corrosion Preventive Compound, Water-Displacing, Ultra-Thin Film, MIL-PRF-81309, Type II, Class 2 (Aerosol), Class 1 (Bulk) For use on all exposed metal and hardware on external chassis, covers, etc. Not intended for exterior areas exposed to the elements.
22. Corrosion Preventive Compound, Water-Displacing, Clear, MIL-DTL-85054, Type I (Aerosol) Water-displacing corrosion preventive. For use on all external surfaces exposed to elements and moisture. For use on chassis, mounting racks, terminal boards, hardware, bus bars, ground straps, etc.
23. Corrosion Preventive Compound, Solvent Cutback, Cold Application MIL-PRF-16173, Grade 4 (Transparent Film) For use on equipment racks, mounts, exposed hardware, etc. For use on exterior surfaces of electrical plugs and connectors. Not intended as a water-displacing compound.
LUBRICATING OILS AND GREASES
24. Lubricating Oil, General Purpose, Preservative (Water-Displacing), MIL-PRF-32033 General lubricating and protection of avionics components, hinges, and quick release devices. Suitable for use where a general purpose lubricating oil with low temperature and corrosion preventive properties is desired.
Appendix 1
25. Grease, Instrument, Ultra-clean, MIL-G-81937 For lubrication of bearings in instruments and related components such as synchros and gyros. Ideally suited for bearings having small tolerances with respect to clearance.
26. Lubricating Oil Instrument, Ball Bearing, High Flash Point, MIL-L-81846 For use in precision instruments and miniature ball bearings. Temperature range of -65 °F (-54 °C) to 302 °F (150 °C).
27. Grease, Aircraft, General Purpose, Wide Temperature Range, MIL-G-81322 For use on blower motors, servomotors, and gyro spin motors.
28. Lubricating Solid Film, Air-Cured, Corrosion Inhibiting, MIL-L-23398 For use on aluminum alloys, copper and copper alloys, steel, stainless steel, titanium, and chromium and nickel bearing surfaces. For use on sliding motion applications such as locks, small internal cables, plain and spherical bearings, tracks, hinges, threads, and cam surfaces. For use in mechanisms that are lubricated for life, and in mechanisms operated at infrequent intervals.
CAUTION: Not to be used in operations consisting of rotary motion over 100 revolutions per minute (rpm) under heavy loads where the possibility of conventional fluid lubricant contamination exists.
Not to be used on bearings containing rolling elements.
CLEANING CLOTH
29. Cloth, Cleaning, Non-Woven Fabric, CCC-C-46, Class 7 No lint, extra heavy duty, moderate wet strength, good absorbency, and disposable. For use when good wet strength and short term rewetting is required, and for wiping critical avionics equipment.
WARNING: Not approved for use in wiping plastic and acrylic surfaces with solvents having a flash point of less than 100 °F (38 °C).
30. Cloth, Cleaning, Lint-Free, MIL-C-85043, Type I or Type II Very low lint, relatively low absorbency, good wet strength, intended for wash and reuse. For use on critical surfaces where low contamination levels are required. Type I preferred for clean room applications.
CAUTION: Not authorized for use with solvents having a flash point of less than 100 °F (38 °C).
31. Cloth, Cheesecloth, Cotton, CCC-C-440, Type II, (28 x 24 weave), Class 1, Unbleached, or Class 2, Bleached Moderate lint, high absorbency, high wet strength, reusable after washing, and disposable. For general cleaning on exterior surfaces of avionics equipment.
For use as a tack rag and final wipe prior to painting.