148_Z-R901_77751_NULL_F_0001_F_NULL_0001_441_U_N_Y_N_N_N_D.PDF

77751 Z-R901 Revision F

04 August 2011

(NGAS CAGE 26512)

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TABLE OF REVISIONS

iii

FOREWORD

This specification presents the protective finish requirements for the A-10 Weapons System and is intended for use by design personnel as a source of information and a means of specification. Engineering drawings and pertinent items’ specifications for subcontractor bids shall call out the appropriate protective finishes in accordance with the requirements of this document.

This document describes the materials, procedures and finish codes that will be used for the surface preparation, surface treatment and finishes required on the A-10 Weapons System.

This specification has been reviewed for EPA 17 toxic chemicals, SARA 313-listed pollutants, as well as ozone depleting substances. No ozone depleting substances were found.

Hazardous air pollutants and toxic materials have been eliminated or minimized to comply with the Air Force Pollution Prevention Program, AFT 32-7080. A reasonable effort has been made to eliminate rather than minimize pollutants and to use environmentally acceptable substitutes.

Certain substitutions, however, have not been made due to their potential unknown deleterious effects on the A-10 weapon system.

It must be understood that the materials, methods, applications and processes can contain toxic and hazardous materials. It is the responsibility of the user to ensure safe and proper use in accordance with all applicable OSHA, EPA, Federal, state and local regulations.

The materials below could not be replaced with alternate environmentally acceptable materials due to the lack of test data or qualified environmentally acceptable alternative materials.

Aerospace industry practice requires that only fully qualified materials be used to assure high reliability or safety of flight considerations.

Material EPA-17 Effort Made to Find Substitute

AMS-QQ-C-320

(was QQ-C-320)

Chromium/Compounds

Surveyed vendors and found no qualified alternative available. Alternative materials have not been fully tested/qualified for wear, hydrogen embrittlement, etc.

AMS-QQ-N-290

(was QQ-N-290)

Nickel Compounds

Surveyed vendors and found no qualified alternative available. Alternative materials have not been fully tested/qualified for wear, corrosion resistance, etc.

AMS-QQ-416

(was

QQ-P-416)

Cadmium/Compounds

Surveyed vendors and found no qualified alternative materials. Candidate materials such as IVD or nickel/zinc plating have not been fully evaluated for corrosion control and dissimilar metals for A-10 part configurations. Procedures and criteria for use of IVD or zinc/nickel plating on A-10 parts must be determined.

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Material EPA-17 Effort Made to Find Substitute

MlL-PRF-85582 and Mll-PRF-23377

Chromium/Compounds

Alternative non-chromated primers are available and supplied by PPG and Deft Chemical.

However, they were not qualified at the time of OEM production and therefore not baselined. It is known that chromated primers generally perform better than non-chromated primers with respect to corrosion protection. Therefore the use of chromated primers is recommended at this time, as the corrosion potential can be greater for an aging such as the A-10.

MIL-STD-865 Cadmium/Compounds

Alternate brush platings are available, but not qualified to original A-10 design requirements.

Cadmium plating is used for rework on high-strength steel and dissimilar metal protection.

Low hydrogen embrittlement alternatives must be evaluated for cadmium replacement.

Dichromate Seal for Sulfuric Acid Anodize, MIL-A-8625

Chromates

Required for enhanced corrosion resistance and paint adhesion to sulfuric acid anodize. Boric-sulfuric acid is a candidate, but must be tested for corrosion resistance to meet original A-10 design requirements.

MIL-STD-1500 Cadmium/Compounds

Alternatives require testing for hydrogen embrittlement in high strength steel (180 ksi UTS and over). Candidates include zinc/nickel, SermeTel, and IVD-type coatings. Bolt Torque- Tension relationships need to be investigated.

MlL-DTL-5541

Chromates, Trichloroethylene.

Methylene Chloride

Chromates are used for corrosion resistance and Adhesion of paints. Alternatives are available, but not qualified to MIL-DTL-5541 requirements as required by the A -10. Additionally, many aerospace companies and chemical supply companies are in the process of looking for alternates to chemical film treatments. To date, no acceptable alternative has been found for A-10 program production parts including spares.

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TABLE OF CONTENTS

TABLE OF REVISIONS .................................................................................................... II

FOREWORD ..................................................................................................................... III

LIST OF TABLES ............................................................................................................. VIII

1.0 SCOPE

1.1 Classification

2.0 APPLICABLE DOCUMENTS

2.1 Government Documents

3.0 REQUIREMENTS

3.1 Instructions

3.1.1 MIL-F-18264 D(1)

3.1.2 Contractor's Finish Specification

3.1.3 Selection of Specifications and Standards Applicable

3.1.4 Material and Processes

3.1.5 Workmanship

3.1.6 General Precautions

3.2 Surface Treatment

3.2.1 Surface Preparation

3.2.2 Plastic Media (abrasive descaling)

3.3 General Exterior Finishes

3.4 Special Exterior Finishes

3.4.1 Wheel and Brake Assemblies

3.5 General Interior Finishes

3.6 Special Interior Finishes

3.6.1 Areas Subject to Corrosive Liquids

3.6.2 Surfaces Subject to Exhaust Gases

3.6.3 Surfaces Exposed to High Temperatures (over 350°F)

3.6.4 Surfaces Exposed to Synthetic Lubricants or Fluids

3.6.5 Decorative Finishes. — Not applicable

3.7 Special Item Finishes

3.7.1 General

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3.7.2 Faying Surfaces. Joints and Seams

3.7.3 Slip Fits and Press Fits

3.7.4 Firewalls

3.7.5 Omission of Paint Coatings

3.7.6 Control Cables and Fittings

3.7.7 Springs

3.7.8 Surfaces Immersed in Oil or Grease

3.7.9 Heat Duct Surfaces

3.7.10 Interior Surfaces of Tanks

3.7.11 Tubing

3.7.12 Attaching Parts

3.7.13 Hinge Surfaces

3.7.14 Electrical Bonding and Electrical Parts

3.7.15 Wood Surfaces

3.7.16 Molded Plastics and Ceramics

3.7.17 Reinforced Plastics Components

3.7.18 Rubber

3.7.19 Fabrics

3.7.20 Shims

3.7.21 Uranium

3.7.22 Beryllium

3.7.23 Cargo Floors. Ramps and Ramp Pressure Doors

3.7.24 Name Plates

3.7.25 Insignia and Markings

3.7.26 Walkways

4.0 DEFINITIONS

4.1 Exterior Surfaces

5.0 DEVIATIONS

5.1 Para. 2.1

5.2 Para. 3.1.1 Specification MIL-F-18264

5.3 Para. 3.1. a

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5.4 Para. 3.1 —Linear Polyurethane

5.5 Para. 3.1.1 a — Production Test Panels

5.6 VOC Compliant. Water Based Paints

5.6.1 Volatile Organic Compound (VOC) Compliant Water Based Primer

5.6.2 VOC Compliant Water Based Primer Limitations

APPENDIX I: FINISH CODES FOR A-10 WEAPONS SYSTEM

APPENDIX II: FINISH CODES FOR A-10 WEAPONS SYSTEM – ORIGINAL

PRODUCTION

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LIST OF TABLES

TABLE I: CHEMICAL SURFACE TREATMENT REQUIREMENTS -- GENERAL

TABLE II: EXTERIOR FINISH REQUIREMENTS – GENERAL

TABLE III: FINISH REQUIREMENTS – COLOR IDENTIFICATION

TABLE IV: EXTERIOR FINISH REQUIREMENTS -- SPECIAL

TABLE V: INTERIOR FINISH REQUIREMENTS – GENERAL

1.0 SCOPE

This specification presents the protective finish requirements for the A-10 Aircraft (Appendix I and II). It describes the materials, procedures, and finish codes that shall be used to protect the aircraft and its component parts, including spares, against deterioration. This specification does not apply to Government furnished or contractor purchased equipment, such as power plants, nor to standard contractor purchased accessories such as electric motors, generators, instruments, switches, hydraulic valves, and similar parts, unless specifically prescribed in the pertinent item specifications or drawings. Contractors are not required to refinish such items provided the finish and color thereon are acceptable to the contractor and the local Government representative and that adequate protection against corrosion is afforded.

However, all surfaces in contact with parts covered herein shall be protected in accordance with the requirements of this specification.

Ground support equipment may be protected to the requirements and methods of Z-R902.

Appendix I applies to all new procurements (spares and new production) and contains approved superseding documentation. Appendix II documents original production finish specifications for the record.

1.1 Classification The protection of this aircraft and its component parts shall be the following type, in accordance with MIL-STD-7179: Type II -Protection for use under moderately severe deteriorative conditions.

2.0 APPLICABLE DOCUMENTS

The following documents of the issue in effect on the effective date of contract shall form part of this specification. In the event of conflict between the contractual documents referenced herein and the requirements of this specification, the contractual documents referenced herein shall govern.

2.1 Government Documents

Specifications

Federal

AMS-QQ-C-320 Chromium Plating (Electrodeposited)

AMS-QQ-N-290 Nickel Plating (Electrodeposited)

AMS-QQ-P-416 Plating, Cadmium (Electrodeposited)

TT-P-28 Paint, Aluminum, Heat Resisting (1200°F)

Military

MIL-A-8625 Anodic Coatings, for Aluminum and Aluminum Alloys

MIL-STD-464 Bonding, Electrical, and Lighting Protection, for Aerospace Systems

MIL-C-5056

Coating Permanent Resin; Process for Application of, to Aircraft Parts (Not for new design)

MIL-DTL-5541 Chemical Conversion Coatings on Aluminum and Aluminum Alloys

MIL-C-6529

Corrosion Preventive, Aircraft Engine (Active for old design.)

AMS-C-8837 Coating, Cadmium (Vacuum Deposited)

MIL-PRF-16173 Corrosion Preventive Compound, Solvent Cutback, Cold Application

AMS-C-27725 Coating, Corrosion Preventive for Aircraft Integral Fuel Tanks

AMS-C-83231

Coating, Polyurethane, Rain Erosion Resistant for Exterior Aircraft and Missile Plastic Parts

MIL-PRF-85285,

Ty. I

Coating, Urethane, High Solids, Aliphatic Isocyanate, for Aerospace Applications

MIL-F-18264 Finish: Organic, Weapon System, Application and Control of ( Not for New Design)

DOD-L-25681 Lubricating Molybdenum Disulfide, Silicone

MIL-PRF-46147 Lubricant, Solid Film, Air cured (Corrosion-inhibiting)

MIL-PRF-81352 Coating, Aircraft Touch-Up

MIL-PRF-8116 Putty, Zinc Chromate, General Purpose

MIL-PRF-23377 Performance Specification Primer Coatings: Epoxy, High Solids

MIL-PRF-85582

Performance Specification Primer Coatings: Epoxy, High Solids

MIL-PRF-3043 Resin Coating: Unpigmented, for Engine Components and Metal Parts

MIL-S-5002 Surface Treatments and Inorganic Coatings for Metal Surfaces of Weapons Systems (Not for New Design)

AMS-S-8802 Sealing Compound, Temperature-Resistant, Integral Fuel Tanks and Fuel Cavities, High Adhesion

MIL-S-38249 Sealing Compound, Firewall

MIL-W-5013 Wheel and Brake Assemblies, General Specification for Aircraft ( Use for replacement purposes only)

MIL-W-5044 Walkway Compound, Nonslip and Walkway Matting, Nonslip, Aircraft ( Use for replacement purposes only)

MIL-W-5050 Walkway, Coating and Matting, Nonslip, Aircraft Application of ( Use for replacement purposes only)

MIL-W-5088 Wiring, Aircraft, Selection and Installation of ( Use for replacement purposes only)

A-10 Program

A-F501 Bonding, Structural High Temperature Aluminum-to-Aluminum, Process for

E-P501 Coating — Rain Erosion, Process for

F-T401 Plating, Cadmium Brush, Process for

G-P101 Sealing — Integral Fuel Tank

G-R301 Cleaning, Acid or Alkaline-Metal, Process for

G-R302 Solvent Cleaning of Metals; Process for

P-P501 Preparation of Reinforced Plastic Surfaces for Painting, Process for

P-P502 Conductive Coating for Reinforced Plastics, Process for

RE-PS-5-1

S-F501

Bonding-Electrical, Grounding and Lightning Protection Bonding, Structural Adhesive — Sandwich Laminates, Aluminum Alloy

T-R201 Cleaning of Titanium and Titanium Alloys

Z-P101 Smoothing and Sealing of External Surfaces

Z-P102 Sealing, Environmental-Requirements and Methods for

Z-P401 Paint -Polyurethane, Application of

Z-P402 Paint-Acrylic, Application of

Z-P501 Coating, Anti Chafing, Process for

Standards

Federal

FED-STD-595 Color, Requirements for Individual Color Chips

Military

MIL-STD-464 Electromagnetic Environmental Effects Requirements for Systems

MIL-STD-865 Selective Brush Plating, Electrodeposition ( Not for New Design)

MIL-STD-889 Dissimilar Metals

MIL-STD-1500

Cadmium-Titanium Plating, Low Embrittlement, Electrodeposition ( Not for New Design)

MIL-STD-7179 Finishes, Coating and Sealants for Protection of Aerospace Weapons Systems

3.0 REQUIREMENTS

3.1 Instructions

3.1.1 MIL-F-18264 D(1)

The following paragraphs, sections, and notes in Specification MIL-F-18264D(1) are applicable: Paragraphs 3.1, 3.2, 3.3, 3.4, 5.1.1.1, 5.1.2, 5.1.2.1, 5.1.2.2, 5.1.3, 5.1.4.3, 5.1.4.4, 5.3.2, 5.5, 5.6.2.1, 5.6.3, 5.10, 5.12, 5.12.1, 5.13, 6.1, 6.3, 6.4, 6.5, Section 8 except paragraphs 8.5 and 8.6, Sections 9 and 10. Notes and references are applicable as guides.

Processes and controls of coatings which are not covered in Specification MIL-F-18264 are as follows:

a) Paragraph 5.1.1 of Specification MIL-F-18264 shall be modified as follows: Shop primer coat (zinc chromate) shall not be applied. Interior and/or exterior surfaces which require primer shall be primed with epoxy-polyamide primer in accordance with Specification MIL-PRF-23377 and applied as soon as practicable after the pretreatment cycle. Whenever necessary, a temporary protective coating shall be used to prevent damage or deterioration of the primed surface and during shop processing, assembly and transportation. Prior to the application the final finish topcoat, the surfaces shall be cleaned and pretreated in accordance with the applicable A-10 or government specifications.

b) Paragraphs 5.8.1 and 5.13 of Specification MIL-F-18264 shall be modified as follows: The finished surface of aliphatic (linear) polyurethane shall be compared for acceptance against an A-10 Program inspection standard.

c) Paragraphs 5.2.2.1 of Specification MIL-F-18264 shall be supplemented as follows:

Interior components/parts which due to their physical shape cannot be coated on the inside with a spray application, such as, hollow welded assemblies, conduits, etc., shall be protected with a "fill and drain" coating of epoxy-polyamide, Specification MIL-PRF-- 23377.

d) Paragraph 5.2.2.2 of Specification MIL-F-18264 -Not applicable.

3.1.2 Contractor's Finish Specification

Applicable, except that the contractor's procedure is outlined as follows:

a) Applicable Paragraphs and Deviations -This specification is complete insofar as the finish requirements are concerned. It includes applicable requirements of Specification

MIL-STD-7179.

b) Detail Areas of the Aircraft -The Procuring Activity will include detail information to describe the finish system for specific areas, e.g., leading edges of reinforced fiber areas.

3.1.3 Selection of Specifications and Standards Applicable.

3.1.3.1 Precedence. In case of conflict between the requirements of this specification and Specification MIL-STD-7179, Specification Z-R901 shall prevail. When an apparent conflict is considered to exist between the contents of this specification and other documents or drawings referenced herein this specification shall take precedence.

3.1.4 Material and Processes

All materials and processes used shall conform to the requirements of the applicable specifications. Use of materials and processes not covered by specifications and other documents referenced herein shall be subject to the approval of the Government procuring activity and specification(s), accompanied by supporting test data therefore, shall be submitted by the Contractor when approval is requested. Materials shall be subject any time to such tests of the applicable specifications as Government procuring activity may require to assure conformance thereto.

3.1.5 Workmanship.

The protective system shall be suitable and satisfactory for service, subject to contract guarantee.

3.1.6 General Precautions

3.1.6.1 Metal Particles. Fabrication and assembly procedures shall preclude the retention of metal particles or pieces such as chips, slivers, rivets, bolts, tools, and metal filings in structures for which no access exists or is afforded to the manufacturer for their removal. A vacuum cleaner providing strong suction shall be employed for frequent cleaning operations in relatively inaccessible areas. Completely enclosed areas shall be inspected prior to installation of the closeout member for (1) absence of debris and (2) proper surface finishes to preclude possibility of corrosion in these areas. Rework of a closed bay area shall be permitted only with specific approval of A-10 Engineering at Hill AFB. When it becomes necessary to remove rivets or perform other minor rework in closed bay areas, the closed area shall be injection sprayed with AMS-S-8802 Class A material to encapsulate the debris or bond the debris to structure.

3.2 Surface Treatment

The Finish Code System (Appendix I, II) is an alphabetical letter system which identifies the surface treatment, the primer coat, and the top-coat, separately and in various combinations, with the appropriate Specifications, Type and Class. The code is posted in the finish column of the Parts List of the drawing. The code is used as a short-hand to the requirements of this section and subsequent sections of this document.

Table I: Chemical Surface Treatment Requirements -- General

Material Surface Treatment

Aluminum alloys 1100, 5052, 6061, 2000 and 7000 series clad alloys, which form interior surfaces, not forming part of fuel tank surfaces. All clad alloys forming exterior surfaces and all chem milled clad aluminum skins.

Chemical

Conversion Coating MIL-DTL-5541, Class 1A.

Non-clad aluminum alloys, 1100, 5052, 2000, 6000 and 7000 series, which form exterior surfaces or to form fuel tank surfaces or receive any dry film lubrication.

Sulfuric Acid Anodize MIL-A-8625, Type II, Class I (Dichromate Seal).

Non-clad aluminum alloys which form interior surfaces.

Chromic Acid Anodize MIL-A-8625, Type I or Sulfuric Acid Anodize MIL-A-8625, Type II optional, except in corrosion prone areas where Sulfuric Acid Anodize will be used.

Aluminum alloys 1100, 5052, and 6061 requiring electrical conductive coating.

Chemical Conversion Coating MIL-DTL-5541, Class 3.

Aluminum alloys, 7000 series, which require abrasion resistance. If fatigue is critical, and for all other alloys, consult Material Engineering.

Sulfuric Acid Anodize (Hard) per MIL-A-8625, Type III.

Steel (low alloy) heat treated below 180,000 psi UTS in corrosive environments and in exterior application.

Cadmium Plate AMS- QQ-P-416, Type II.

Steel (alloy) heat treated to 180,000 psi UTS and over.

Vacuum Cadmium Plate

AMS-C-8837, or Electrodeposited per

MIL-STD- 1500 (Not for New Design).

Corrosion and heat-resistant steel (except 400 series), 17-7PH, 17-4PH, AM350, PH15-7, PH 13- 8M0 and A-286.

Passivate MIL-S-5002. (Not for New Design)

Copper alloys, brasses and bronzes, uranium Cadmium Plate AMS-QQ-P-416, Type II.

Titanium alloys.

Surface Treatment Specification T-R201.

Monel, tungsten and Inconels. No Surface Treatment.

NOTES TO TABLE I:

1. Aluminum surfaces of adhesive bonded assemblies shall be surface treated by chemical conversion per MIL-DTL-5541, Class 1A in lieu of sulfuric acid anodize.

2. Steel bearing surfaces or journals need not be plated.

3. Parts operating or continuously enclosed in grease need not be plated.

4. Electrical parts need not be cadmium plated at the grounding junction.

5. Parts to be joined by soldering need not be cadmium plated.

6. Cadmium plated parts shall not be interference fit installed in titanium. Use tin plating instead.

7. Cadmium plated parts shall not contact titanium aircraft structure, titanium engine surfaces or be exposed to temperatures in excess of 450°F.

3.2.1 Surface Preparation

All metal surfaces, regardless of whether they are to be painted or are specifically excluded from painting requirements, shall be surface treated in accordance with Specification MIL-S- 5002D(2), except as modified in Paras. 3.7.12.1, 3.7.10.3 and 3.7.11 of this specification and as follows:

a) Paragraph 3.3 of MIL-S-5002 D(2), Surface Conditions

1. Acid cleaning and applicable inspection of aluminum and aluminum alloy surfaces shall be in accordance with Specification G-R301.

2. Surface preparation prior to structural adhesive bonding shall be in accordance with Specification S-F501 or A-F501.

b) Paragraph 3.4.1 of MIL-S-5002 D(2), Organic Soil Remover

1. Vapor degreasing, except titanium and titanium alloys, shall be performed in accordance with Specification G-R302.

2. Cold solvent degreasing, except titanium and titanium alloys shall be performed in accordance with Specification G-R302.

3. Titanium and titanium alloys shall be surface prepared in accordance with Specification T-R201.

c) Paragraph 3.4.2.1 of MIL-S-5002 D(2), Cleaning Aluminum and Aluminum Alloys

1. Acid cleaning of aluminum and aluminum alloys shall be in accordance with Specification G-R301.

2. Alkaline cleaning of aluminum and aluminum alloys shall be in accordance with Specification G-R301.

3. Preparation of aluminum alloys prior to structural adhesive bonding shall be in accordance with Specification S-F501 or A-F501.

d) Paragraph 3.4.2.2 of MIL-S-5002 D(2), Cleaning High-Strength Steel

1. High-strength steel shall be cleaned in accordance with Specification G-R301.

e) Paragraph 3.4.2.3 of MIL-S-5002 D(2), Cleaning Low-Strength Steel

1. Low-strength steel shall be cleaned in accordance with Specification G-R301.

f) Paragraph 3.4.2.4 of MIL-S-5002 D(2), Cleaning of Corrosion and Heat Resisting Metals

1. Parts with pitted surfaces or showing intergranular attack shall be submitted for Material Review Board (MRB) action.

2. Titanium and titanium alloys shall be cleaned and descaled in accordance with Specification T-R201.

3. Ferrous alloys shall be acid cleaned in accordance with Specification G-R301.

g) Paragraph 3.4.2.6 of MIL-S-5002 D(2),Titanium and Titanium Alloys

1. Titanium and titanium alloys shall be surface cleaned in accordance with Specification T-R201.

2. Prior to the application of organic coatings, titanium alloys shall be prepared in accordance with Specification T-R201.

MIL-S-5002 D(2) is inactive for new design and no longer used except for replacement purposes.

3.2.2 Plastic Media (abrasive descaling)

Plastic media abrasive blasting can be used to remove organic coatings on metallic surfaces up to 0.016 inches for 3.0 MOH and 0.032 inches for 3.5 MOH media. Parts should be cleaned when using plastic media in accordance with Technical Order 1-1-8 and procedures approved by the System/Item Manager or Contractor’s Materials Engineering section.

3.3 General Exterior Finishes

The protection scheme for the A-10 Weapons System is in agreement with Air Force policy that all aircraft be painted as a prime means of corrosion protection and as in general accordance with Specification MIL-STD-7179. The basic topcoat shall be an aliphatic isocyanate urethane coating meeting the requirements of Specification MIL-PRF-85285 Ty. I.

The primer shall be an epoxy-polyamide coating meeting the requirements of Specification MIL-PRF-23377G. The general finish requirements for the exterior surfaces of the A-10 Weapons System are shown in Table II. Color identifications, in accordance with FED-STD- 595, are shown in Table III.

Table II: Exterior Finish Requirements – General

Material

Finish System

High- Solids Primer

MIL-PRF-23377J

Epoxy-Polyamide Thickness (mils)

High-Solids Top Coat Linear Polyurethane MIL-PRF-85285 Ty. I

Aluminum alloys 1100, 3003, 5052, 6061, clad alloys in the 2000 and 7000 series.

0.60 to 0.90

1.7 to 2.3

Non-clad aluminum alloys in the 2000, 6000 and 7000 series, and other high-strength aluminum alloys.

Plated, metal-sprayed, hot dip coated parts.

Titanium, corrosion and heat-resistant alloys.

All metals not covered by the above.

Table III: Finish Requirements – Color Identification

FED-STD-595

Gloss

Color Number

Predominant Color

Other Source’s Color Name

Full Gloss

11136 Red Insignia Red

12197 Orange International Orange

13538 Yellow Orange Yellow

15044 Blue Insignia Blue

16473 Gray Aircraft Gray

17038 Black Gloss Black

17178 Aluminized Silver/Aluminum

17875 White Insignia White

Semi Gloss 21136 Red Maroon

Lusterless 36231 Gray Medium Gray

37038 Black Black

3.4 Special Exterior Finishes

Special finishes for special areas are listed in Table IV with the FED-STD-595 numerical color callout.

Table IV: Exterior Finish Requirements -- Special

Aircraft Part FED-STD-595 Color No.

MIL-Spec. No.

All Exterior Areas, except as noted 16473 MIL-PRF-85285Ty. I

Battery Compartment 16473 MIL-PRF-85285Ty. I

Flap Wells 16473 MIL-PRF-85285Ty. I

Landing Gear 16473 MIL-PRF-85285Ty. I

Wheel and Brake Assemblies 16473 MIL-W-5013

Gun Gas/Blast 16473 or 17038

MIL-PRF-85285Ty. I

Plastic Parts, except as noted 16473 MIL-PRF-85285Ty. I

Leading Edges at ±15° to line of flight (See_Section 3.7.17)

17038

Anti-Glare at Nose Section 37038 MIL-PRF-85285Ty. I

Speed Brake, Open 11136 MIL-PRF-85285Ty. I

Anti-Skid Walkway 37038 MIL-W-5044, Type I

Light Reflective, as Nacelle Door Interior 17875

3.4.1 Wheel and Brake Assemblies

The wheel and brake assemblies shall be finished in accordance with MIL-W-5013. MIL-W- 5013 is inactive for new design and no longer used except for replacement purposes.

3.5 General Interior Finishes

The general finish requirements for the interior surfaces of the A-10 Weapons System shall be as specified in Table V.

Material

Finish System High-Solids Epoxy

MIL-PRF-23377J

Aluminum alloys 1100, 3003, 5052, 6061, clad alloys in the 2000 and 7000 series.

Non-clad aluminum alloys in the 2000, 6000 and 7000 series, and other high-strength aluminum alloys.

Plated, metal-sprayed, hot dip coated parts.

Titanium, corrosion and heat-resistant alloys. 0.60 to 0.90

All metals not covered by the above. 0.60 to 0.90

Table V: Interior Finish Requirements – General

3.6 Special Interior Finishes

3.6.1 Areas Subject to Corrosive Liquids

The surfaces of the storage battery compartment, adjacent areas, and components subject to spillage and/or spray shall be protected with epoxypolyamide primer per Specification MIL- PRF-23377J and an aliphatic isocyanate urethane topcoat meeting the requirements of Specification MIL-PRF-85285, Ty. I per Table II.

3.6.2 Surfaces Subject to Exhaust Gases

Interior surfaces and components exposed to exhaust gases, gun and rocket blast areas and other surfaces that are known to be subject to corrosive conditions or drippage of corrosive fluids inclusive of the gun bay shall be protected with epoxy-polyamide primer per Specification MIL-PRF-23377J and aliphatic isocyanate urethane topcoat color shall match the general weapon system schedule. Where inordinately high temperatures or excessively corrosive conditions are encountered, the method of protection shall be designated on the drawing.

3.6.3 Surfaces Exposed to High Temperatures (over 350°F)

Where the temperature exceeds 350°F, the area shall be protected with heat-resistant finish in accordance with Specification TT-P-28. The color shall be aluminum as applied.

3.6.4 Surfaces Exposed to Synthetic Lubricants or Fluids

Surfaces exposed to synthetic lubricants shall be protected with a epoxy-polyamide primer per Specification MIL-PRF-23377J with an aliphatic isocyanate urethane topcoat meeting the requirements of Specification MIL-PRF-85285, Ty. I per Table II.

3.6.5 Decorative Finishes. — Not applicable.

3.7 Special Item Finishes

3.7.1 General

Where any preceding requirements are in conflict with the requirements of this section, the requirements of this section shall prevail.

3.7.2 Faying Surfaces. Joints and Seams

3.7.2.1 Definition of Similar and Dissimilar Metals. The grouping of the more commonly used aircraft materials, as established by MIL-STD-889B, apply, except that the standard shall not be construed as exempting attaching parts from the protection requirements of paragraph 3.7.12.

3.7.2.2 Surfaces of Similar Metals. All seams in which the faying surfaces are similar metals, as defined in paragraph 3.7.2.1, shall be protected by applying to each surface the same number of coats of primer as are prescribed for interior surfaces (see paragraph 3.5).

Exception to the foregoing are:

a) The primer shall be as specified in Table V.

b) Faying surfaces in integral fuel tanks (see paragraph 3.7.10).

c) Faying surfaces that are to be adhesively bonded shall be surface treated and processed, as specified in the approved bonding procedures prescribed for the assemblies concerned.

d) In addition to the required primer coatings, seams and edges in exterior locations shall be sealed per Specifications Z-P101 and Z-P102.

3.7.2.3 Surfaces of Dissimilar Metals. Each surface shall receive primer per Table V, except as specified in paragraph 3.7.12.

3.7.2.4 Sealing. Openings which are not required for aircraft operation shall be sealed to prevent fluid entry from external sources. Sealing around access plates shall be accomplished by fabricating formed-in-place seals permanently fixed to structure per Specification Z-P101.

3.7.2.5 Gastight. Fuel Tight and Watertight Seams. Seams shall be sealed in a manner that will prevent leakage or ingress of fuel, carbon monoxide, water or other liquids, where necessary. Such sealing shall be accomplished in accordance with Specifications G-P101, Z- P101, or Z-P102 as applicable.

3.7.2.6 Defect Filling. The use of filling material for the purpose of sealing nicks, dents, gouges or poor joints is prohibited.

3.7.2.7 Cut Edges. The edges of metals in exterior locations shall be smooth and free of burrs.

3.7.2.8 Surface Insulation. Not applicable.

3.7.3 Slip Fits and Press Fits

3.7.3.1 Masking Special Sites. Holes and associated chamfer or bevel intended as a site for a press fit or slip fit installation shall be masked to prevent primer or topcoat from coating the surfaces prior to the installation of an item to be swaged.

3.7.3.2 Press Fits. Pressing shall be accomplished with epoxy-polyamide primer per Specification MIL-PRF-23377J except for parts permanently housed in oil. Parts permanently housed in oil shall be assembled with the oil to be used in the housing. The completed assembly shall then be finished as specified in the FINISH REQUIREMENTS — GENERAL.

Tables II and V.

3.7.3.3 Slip Fits. — Slip fits shall be assembled using epoxy-polyamide primer per Specification MIL-PRF-23377J. Where these materials are not compatible with the function of the part, preservative compound conforming to Specification MIL-PRF-16173, grade 2, may be used.

3.7.3.4 Touching-up Of Uncoated Areas. — All uncoated areas of the bevel or chamfer existing after the press fit or slip fit installation shall be touched up per the drawing requirements.

3.7.4 Firewalls

Firewall sealing compound conforming to Specification AMS 3374, shall be used to seal fasteners, seams, and pertinent surface areas of the firewalls. This will include firewalls in the engine nacelle area and the APU compartment.

3.7.5 Omission of Paint Coatings.

3.7.5.1 Functional Surfaces. Special care shall be exercised to ensure that paint is not applied to working surfaces, to adjustable threads, or to oil or drain holes. Paint shall not be applied to fittings in a manner that may cause malfunctioning.

3.7.5.2 Corrosion, Heat Resistant and Titanium Parts. Corrosion, heat-resistant and titanium parts which contact fuel shall have surface prepared, as applicable, in conformance with paragraph 3.2.1, except for plumbing lines, valves, pumps, etc. covered by systems specifications. All detail titanium parts in contact with fuel shall be coated with material in accordance with Specification AMS-C-27725 and applied in accordance with the coating manufacturer’s directions.

3.7.6 Control Cables and Fittings.

Finishes on A-10 source control drawings are governed by the OEM approved vendor drawing, unless otherwise specified. In all other cases, Z-R901 is applicable in accordance with engineering drawing call outs.

3.7.7 Springs

Springs that are closely coiled, preventing the application of plating to internal surfaces, shall either be primed per Table V or coated with a corrosion preventive coating in accordance with Specification MIL-PRF-16173 Grade 2.

3.7.8 Surfaces Immersed in Oil or Grease

Parts which are housed in lubricating oil, or grease shall have baked resin coatings conforming to Specification MIL-PRF-3043 applied in accordance with Specification MIL-C-5056. Parts constructed of corrosion-resistant materials need not be coated unless they contact dissimilar metals. Functional surfaces, such as bearing surfaces, shall not be coated. MIL-C-5056 is inactive for new design and no longer used, except for replacement purposes.

3.7.9 Heat Duct Surfaces

Aluminum alloys; chemical conversion or anodize coating on duct interior, as applicable. Outer surface of ducts shall be coated per Table V.

3.7.10 Interior Surfaces of Tanks

3.7.10.1 Metal Fuel Tanks

3.7.10.1.1 Welded Fuel Tanks

The inside surfaces of aluminum alloy tanks (including external auxiliary fuel tanks) shall not be painted. Spare tanks shall be thoroughly cleaned, then sloshed with corrosion-preventive compound conforming to Specification MIL-C-6529, Type III, then drained. MIL-C-6529 is inactive for new design and used only for replacement purposes on existing systems.

3.7.10.1.2 Integral and Riveted Fuel Tanks. The surface of integral and riveted fuel tanks shall be sealed and finished as follows:

Aluminum alloy parts (except plumbing lines, valves, pumps, etc., covered by system specifications) which contact fuel shall be surface treated with an anodic coating, Specification MIL-A-8625, Type II, dichromate-seal. Steel parts which contact fuel shall be surface treated as specified in paragraph 3.2. The parts shall be coated with a corrosion preventive coating per Specification AMS-C-27725 and applied per manufacturer’s instructions.

3.7.10.2 Lubricating Oil and Hydraulic Tanks. The inside surfaces of oil tanks made of corrosion- resistant materials shall require no coating. Tanks made of other materials shall be coated with material conforming to Specification MIL-PRF-3043 applied in accordance with Specification MIL-C-5056. MIL-C-5056 is inactive for new design and no longer used, except for replacement purposes.

3.7.10.3 Miscellaneous Tanks (Aluminum Alloy, for Water, Anti-freeze, Alcohol, etc.)

The inside surface of portable water tanks shall not be surface treated. The interior surfaces of tanks used to store other materials shall be surface treated in accordance with Specification MIL-A- 8625 or Specification MIL-DTL-5541.

3.7.11 Tubing

3.7.11.1 Plumbing Line (Fuel, Water, Hydraulic, and other Tubing). Surface treatment of tubing shall be accomplished after forming, but prior to the installation of nuts, sleeves and fittings. Internal and external surfaces of aluminum alloy tubing shall be surface treated in accordance with Specification MIL-DTL-5541 or Specification MIL-A-8625 insofar as is practicable, except anodic coating shall not be used for hydraulic lines. Stainless steel tubing containing more than 14% chromium shall be passivated in accordance with Specification G- R301. The use of 400 series CRES steels is prohibited, unless authorized by the cognizant Materials Engineering. Oxygen lines shall be treated on the external surface only. Tube assemblies shall be cleaned in accordance with Specification G-R302 paragraph 3.1.3 prior to application of paint coatings. No paint coating shall be applied to the internal surface of oxygen tubing, airspeed indicator tubing or other designated plumbing lines. All plumbing installed in the aircraft shall be protected as described in this section.

3.7.11.1.1 Permanent Installation- Aluminum alloys. — All aluminum alloy plumbing lines and fittings shall have one coat of epoxy-polyamide primer per Specification MIL-PRF-23377J applied except for the areas within a suitable distance from the ends to accommodate the fittings required for installation. (Refer to the requirements at the end of this section.) This coating shall be applied after fabrication and prior to installation in the aircraft. All plumbing lines and fittings shall have additional primer applied to uncoated areas as required following the installation joining operation. Plumbing lines and fittings which are installed in interior locations in the aircraft shall not be further coated. Plumbing lines and fittings which are installed in exterior locations in the aircraft shall have the complete exterior paint system applied; except for the area beneath the fittings (see Table II). The color scheme shall match the background color.

Corrosion-resistant steels — All passivated corrosion-resistant steel plumbing lines and fittings installed in interior locations in the aircraft require no primer or topcoat paint system. Passivated corrosion-resistant steel plumbing lines and fittings installed in exterior locations in the aircraft shall have one coat of epoxy-polyamide primer per Specification MIL-PRF-23377J and a linear polyurethane topcoat per Specification MIL- PRF-85285, Ty. I applied (see Table II), except for the areas within a suitable distance from the free ends to accommodate the fittings required for installation. These coatings shall be applied after fabrication and prior to installation in the aircraft. All exterior located plumbing lines and fittings shall have additional primer and topcoat applied to uncoated areas as required following the installation joining operation. The topcoat color scheme shall match the background color.

Finishing (all materials) — Finish, which has been damaged during installation, shall be retouched. Such lines, where fittings are inaccessible for inspection and refinishing as may be required in service and are so oriented that fluids can collect on or behind the fittings, shall have exposed surfaces between the parts sealed with the designated sealant. After sealing, the seals and the surfaces adjacent to them shall receive the prescribed paint finish. However, when approved by the applicable drawing, overpainting of surfaces coated with a sealing compound may be omitted.

NOTE: “UNLESS OTHERWISE SPECIFIED BY THE DRAWING, THE FOLLOWING

REQUIREMENTS SHALL APPLY FOR TUBING REQUIRING EXTERIOR PAINTING:

1. TUBE ASSEMBLIES WITH WIGGINS FERRULES:

THE PAINT SHALL TERMINATE 1/8” BEFORE THE FERRULE TO 1/8” UNDER THE

FERRULE.

2. TUBE ASSEMBLIES THAT ARE FLARED WITH “B” NUTS AND SLEEVES:

THE PAINT SHALL TERMINATE 1/8” BEFORE THE SLEEVE (SLEEVE AGAINST FLARE)

TO 1/8” UNDER SLEEVE.

3. TUBES WITH BEADED ENDS:

THE PAINT SHALL TERMINATE AT THE END OF THE TUBE.”

3.7.11.1.2 Removable Installations. Plumbing lines and fittings which are known to require periodic removal in service shall be coated per paragraph 3.7.11.1.1, except for the areas within a suitable distance from the free ends to accommodate the fitting required from installation. After installation, fittings and unprotected portions of the tubing shall receive a coating of corrosion preventive compound conforming to Specification MIL-PRF-16173, Grade 4, which shall seal all exposed spaces between the parts. Contractor prepared maintenance instructions shall require periodic reapplication of this material in service.

3.7.11.2 Structural Aircraft Tubing.

3.7.11.2.1 Aluminum Alloy. Interior surfaces of aluminum alloy tubing shall be protected in accordance with the finish schedule for interior surfaces as per Tables I and V.

3.7.11.2.2 Steel. The interior and exterior surfaces of structural steel tubing shall be finished as per Table I, except as follows: Tubings, which are completely closed by welding or where the application of primer to the interior surface is neither practicable nor effective, the interior surface shall be protected with corrosion preventive compound in accordance with Specification MIL-PRF-16173, Grade 4. After the interior surface has been treated, the exterior surface shall be finished per Table V.

3.7.11.3 Copper Alloy. Corrosion-Resistant Alloy and Heat-Resistant Alloy Tubing. — Interior and exterior surfaces of copper alloy, corrosion-resistant alloy and heat-resistant alloy tubing need not be painted, except as required for dissimilar metal contact.

3.7.11.4 Mechanical Attachment. Tubular parts which have end fittings mechanically attached shall be sealed with an approved sealing material designated by the applicable drawing.

3.7.12 Attaching Parts

3.7.12.1 General Finish. Attaching parts, such as nuts, bushings, spacers, washers, rivets, high- shear rivets, screws, self-tapping screws, sleeves for “shakeproof’ fastener studs, self-locking nuts, “speed nuts,” clamps, etc., need not be painted in detail except when dissimilar metals are involved in the materials being joined together. Such parts or the surfaces with which they are in contact shall receive a coat of primer or sealant which shall be wet at the time of installation. Fasteners, other than quick-release type, located in exterior locations shall be installed with a designated sealant. Sealant shall not be applied to the threaded portion of structural fasteners for which torque or installation requirements are established without the sealant.

3.7.12.2 Close Tolerance Bolts. Close tolerance bolts shall be coated with compound or sealant conforming to Specification MIL-PRF-16173, Grade 1, or wet primer prior to installation.

3.7.12.3 Adjustable Parts. Threads of adjustable parts such as tie rods, turn-buckles, etc., shall be lubricated and protected both before and after assembly with antiseizing compound conforming to Specification DOD-L-25681 or an equivalent material, or protected with corrosion-preventive compound conforming to Specification MIL-PRF-16173, Grade 2.

3.7.12.4 Touchup. All attaching parts shall be touched up, if needed, after installation in accordance with the general weapons system schedule. Topcoats shall be applied over the primer to match the color of adjacent exterior surfaces when necessary. Nuts and heads of bolts in joints that are subsequently lubricated need not be touched up.

3.7.13 Hinge Surfaces

Thin solid film lubricant coating per Specification MIL-PRF-46147 shall be applied to all piano hinges. The use of graphite or carbon lubricants is prohibited.

3.7.14 Electrical Bonding and Electrical Parts

3.7.14.1 Connections. Electrical bonding and ground connections conforming to Specifications RE-PS-5-1 and MIL-STD-464 shall be finished in accordance with the general finish schedule after installation. All edges shall be sealed after installation with Specification AMS-S-8802, sealing material.

3.7.14.2 Conduits Electrical conduits shall be protected as follows:

a) Internal surfaces of conduits do not require a primer and/or topcoat.

b) Aluminum 1100, 3003, 5052, 6061, clad 2014, clad 2024 and clad 7075 shall receive primer per Table V.

c) Exterior surfaces of conduits and junction boxes shall match the applicable color scheme.

d) Wires coated with plastic materials and braided wire do not require a finish.

3.7.14.3 Electrical Junction Boxes. In compliance with MIL-W-5088, aluminum junction boxes shall be surface treated in accordance with MIL-DTL-5541 Cl. 3. (Note: MIL-W-5088 is inactive for new design and is no longer used except for replacement purposes. New design should refer to SAE AS50881.) Prior to priming, a suitable masking dot may be placed over the mounting/grounding installation hole(s) where the plate mates to the component surface (terminating ground). The interior and exterior of the box shall be coated with epoxy-polyamide primer and polyurethane topcoat as shown in Table II. Topcoat color shall be FED-STD-595 Color No. 16473 (Table III). Masking dots shall be removed prior to component installation.

3.7.15 Wood Surfaces

Not applicable.

3.7.16 Molded Plastics and Ceramics

Transparent plastic parts shall not be painted. Other plastic parts (except fiberglass laminates, antennas and magnetic airborne detector housings) need not be painted, except for color matching purposes. Under no circumstances shall plastic or ceramic insulators for radio antennas, etc., be painted.

3.7.17 Reinforced Plastics Components

Leading edges of glass fiber reinforced plastic radomes, antennas, magnetic-airborne detectors, conforming to Specification MIL-R-7705 (Note: MIL-R-7705 is not for new design and has not been replaced.) exposed to the airstream shall be protected with a rain erosion, heat-resistant finish conforming to Specification AMS-C-83231. The finish shall be applied in accordance with Specification E-P501. No area of transparent components, whether glass or plastic, shall be painted. Plastic part surfaces other than those described above may be painted for color matching purposes.

3.7.18 Rubber

Not applicable.

3.7.19 Fabrics

Not applicable.

3.7.20 Shims

When specified by Engineering Drawing, shims shall be installed using wet or dry epoxy primer per Specification MIL-PRF-23377J.

3.7.21 Uranium

Not applicable.

3.7.22 Beryllium

Not applicable.

3.7.23 Cargo Floors. Ramps and Ramp Pressure Doors

Not applicable.

3.7.24 Name Plates

Identification, markings and Name Plates shall be in accordance with Z-R701.

3.7.25 Insignia and Markings

Insignia and markings shall be applied per Table III using any one or combination of painting, stenciling, silk screen, or decalcomania techniques.

3.7.26 Walkways

Walkways shall be finished with anti-skid walkway paint conforming to Specification MIL-W- 5044, Type I, and applied in accordance with Specification MIL-W-5050. (Notes: MIL-W-5044 has been canceled, but may still be procured for spares and existing design. MIL-W-5050 is inactive for new design, except maybe used for replacement purposes.) Walkway coat shall be applied over epoxy-polyamide primer conforming to Specification MIL-PRF-23377J.

4.0 DEFINITIONS

4.1 Exterior Surfaces

All surfaces that are normally exposed to the external environment during flight or on the ground and all of those interior surfaces which may be wetted with water or other corrosive fluids are considered exterior surfaces. These surfaces include wheels and gear, wheel wells and their fairings, dive brakes, wing flaps, gun compartment, avionics compartments with louvered openings and ladder and battery compartments.

5.0 DEVIATIONS

It is the intent of the deviations in Sections 5.1 through 5.5 to explain and to detail the reasons for the deviations to Specification MIL-STD-7179. Section 5.6 describes alternate VOC compliant paints.

5.1 Para. 2.1

A- 10 Finish Document has been included to meet the requirements of the aircraft vehicle.

5.2 Para. 3.1.1 Specification MIL-F-18264

The listing includes the Specification MIL-F-18264 paragraphs, sections, and notes that are applicable to the aircraft finish system.

5.3 Para. 3.1. a

Shop-coat primer (zinc chromate primer) is not applicable to the aircraft finish system for the following reasons: The primer system for the aircraft is epoxy-polyamide primer in accordance with Specification MIL-PRF-23377J. Therefore, in order to facilitate the application of the topcoat system during the final paint operation, all other exterior surfaces shall be primed as detail parts. Detail parts containing deep recesses or in assemblies where it is impractical to obtain a uniform spray or in local repair areas, the coating thicknesses are waived. When applying a flash prime coat in enclosed areas of the aircraft, over-spray of the primer is allowed and acceptable. Cleaning and scuffing to activate the primed surfaces prior to the application of the topcoat are described in applicable finish code specifications. The system has been demonstrated to provide the necessary adhesion and protection.

5.4 Para. 3.1 —Linear Polyurethane

The nature of the linear polyurethane system is such that some orange peel must be expected.

This characteristic does not affect the functional capability of the protection system. In enclosed areas of the aircraft, roughness of all the polyurethane due to over-spray or fogging of the MIL-PRF-23377J primer is acceptable.

5.5 Para. 3.1.1 a — Production Test Panels

Production test panels shall be prepared to provide a spot check of the working properties of the paint and then stored for future reference.

5.6 VOC Compliant. Water Based Paints

5.6.1 Volatile Organic Compound (VOC) Compliant Water Based Primer

The use of compliant MIL-PRF-85582, Type I, Class C is permitted as an alternate for MIL- PRF-23377J high solids primer. See Section 5.6.2 for limitations.

5.6.2 VOC Compliant Water Based Primer Limitations

The use of compliant MIL-PRF-85582, Type I, Class C is permitted as an alternate for MIL- PRF-23377J high solids primer, except that wet installation of fasteners, bushings, or hardware shall not be accomplished with MIL-PRF-85582 primer. Wet installing fasteners, bushings or hardware may be accomplished with MIL-PRF-81733 sealant for permanent installations.

P/S 870 sealant meeting MIL-PRF-81733 is manufactured by PPG Aerospace ASC Philadelphia, 823 East Gate Drive Mount Laurel, N.J. 08054, may be used when authorized by the System/Item Manager. PR-2001 manufactured by PPG Aerospace maybe used as an alternate, if approved by the Air Force A-10 SPO at Hill AFB.

APPENDIX I: FINISH CODES FOR A-10 WEAPONS SYSTEM

1. The following alphabetical coding will be used to specify:

(1) Surface Preparation

(2) Surface Treatment

(3) Combinations of surface finishes and coatings required for metallic and non-metallic parts.

2. Surface preparation is the various cleaning operations. Surface treatment includes conversion coatings, anodize, plating and passivation. Surface finishes and coatings include paint, lubricants, anti-chafe coating and plating not requiring a topcoat, i.e., chromium plating.

3. The proper Finish Code to be designated can be obtained from the Finish Specification (Z- R901).

4. The Finish Code will designate the operation and the approved material and process specification to be used by manufacturing.

5. The Finish Code will consist of the (1) title of the operation(s), (2) the material specification(s) to be used, (3) the process specification(s) to be used, and (4) remarks.

Specifications when called out on purchase orders or operations sheets must bear the…