CHANGE REFERENCE. AC NO: 48.18-1A CHG 1 DATE: 5/12/75
ENT OF FRA SPORT
ADVISORY
FO STATES OF CIRCULAR
DEPARTMENT OF TRANSPORTATION DEPARTMENT OF TRANSPORTATION OST-FOB-10A, TAD-494.7 800 INDEPENDENCE AVE S.H.
FEDERAL AVIATION ADMINISTRATION WASH., D.C. 20590-
ACCEPTABLE METHODS, TECHNIQUES, AND SUBJECT: PRACTICES-AIRCRAFT INSPECTION AND RE, PAIR
1. PURPOSE.
This change transmits new and revised material for Advisory Circular 48.13-1A.
2. PRINCIPAL CHANGES.
a. Corrections have been made to paragraph 318 and Figure 10.1.
b. Chapter 2, Section 3, has been revised to add Selective Plating in aircraft maintenance.
Chapter 4, Section 6 has been revised to add handling and care of aircraft recovered from water immersion.
c. A new Section 5, Cabin Interior Materials- Fire Protection Qualities, has been added to Chapter T.
d. New information on tire slippage and maintenance has been added to Section 1 of Chapter 8.
3. HOW TO GET THIS PUBLICATION.
Copies of this change to AC 43.18-1A may be obtained by ordering from:
Superintendent of Documents U.S. Government Printing Office Washington, D.C. 20402 For up-to-date information on how to order, and the price of this publication, check with the closest FAA office or obtain the latest copy of Advisory Circular 00-2, Advisory Circular Checklist and Status of the Federal Aviation Regulations. This checklist may be obtained without charge by requesting from:
Department of Transportation Publications Section, TAD 443.1 Washington, D.C. 20580 Initlated by: AFS-830 PoP Stally R. P. SKULLY, Director Flight Standards Service Initiated by:
PAGE CONTROL CHART Remove Pages Dated Insert Pages Dated i thru iv 1972 i 1972 ii thru iv 1975 73 and 74 1972 73 thru 73-3 1975 74 1972 127 and 128 1972 127 1972 128 thru 128-3 1975 189 and 140 1872 189 1972 140 thru 140-1 1975 149 and 150 1972 149 1972 150 1975 165 and 166 1972 165 1975 166 1972
AC 43.13-1A Page 1 1972
TABLE OF CONTENTS Chapter 1. AIRCRAFT WOOD STRUCTURES
• Section 1. MATERIALS AND PRACTICES Paragraph Page Materials
2. Replacement of Drainholes and Skin Stiffeners Control Surface Flutter Precautions Gluing Precautions. - Б. Preparation of Wood Surfaces for Gluing .
6. Glues
7. Mixing of Resin Glues 4
8. Spreading of Glue
9. Assembly Time in Gluing
10. Gluing Pressure 11 Scarf Joints 12 Splicing of Spars
18. Splicing of Box Spar Webs
14. Replacing Solid-Type Spars with Laminated Type
15. Spar Longitudinal Cracks and Local Damage
16. Elongated Holes in Spars
17. Rib Repairs
18. Plywood Skin Repair 9
19. Repairs to Single Curvature Plywood Skin 10
20. Repairs to Double Curvature Plywood Skin 10
21. Splayed Patch 10
22. Surface Patch 16
23. Scarf Patch 17
24. Plug Patches 17
25. Fabric Patch 28
26.-86. Reserved 28 Section 2. FINISHING WOOD STRUCTURES
87. General 24
88. Precautions to be Observed 24
89. Finishing of Interior Surfaces 24
40. Finishing of Exterior Surfaces 24
41. Finishing of End Grain Surfaces 25
42. Finishing with Fabric or Tape 25
48.-58. Reserved - 25 Chapter 2. AIRCRAFT METAL STRUCTURES Section 1. REFERENCES AND PRECAUTIONARY MEASURES
54. References 27
55. Flutter and Vibration Precautions 27
66. Brazing 28
07.-67. Reserved 28 Section 2. WELDING
68. General 29
69. Steel Parts Not to be Welded . 82
70. Repair of Tubular Members 82
Page lI AC 43.13-1A CHG 1 1975 TABLE OF CONTENTS-Continued Paragraph Page
71. Repalr by Welded Sleeve 35
72. Repair by Bolted Sleeve 35
79. Welded-Patch Hepair 35
74. Splicing Tubing by Inner Sleeve Method 36
75. Splicing Tubing by Outer Sleeve Method 38
78. Splicing Using Larger Diameter Replacement Tubes 39
77. Repairs at Bullt-In Fuselage Fittings 40
78. Engine Mount Repairs 40
79. Landing Gear Repairs 40
80. Built-Up Tubular Wing or Tall Surface Spars 47
81. Wing and Tail Brace Struts 47
82. Repairs to Welded Parts 47
83. Stainless Steel Structure 47
81.-94. Reserved 48 Section 3. METAL REPAIR PROCEDURES
95. Riveted or Bolted Steel Truss-Type Structures 49
96. Aluminum Alloy Structures 48
97. Selection of Aluminum for Replacement Parts 50
98. Heat Treatment of Aluminum Alloy Parts 50
09. Riveting 51
100. Repair Methods and Precautions for Aluminum Structure 54
101. Repairing Cracked Members -_--
102. Steel and Aluminum Fittings --
103. Castings * 104. Selective Plating in Alrcraft Maintenance 73 *
105.-114. Reserved 73-3 Section 4. REPAIR OF LAMINATE STRUCTURES
115. General 74
110.-128. Reserved 78 Chapter 3. FABRIC COVERING Section 1. PRACTICES AND PRECAUTIONS
127. Textile Materials 81
128. Covering Practices 81
129. Preparation of the Structure for Covering .
130. Fabric Seams --
181. Covering Methods 84
132. Relnforcing Tape 86
133. Lacing 86
134. Stitch Spacing 81 185, Surface Tape (Finishing Tape) - 87
136. Special Fasteners
137.-147. Reserved 91 Section 2. DOPING
148. Application of Aircraft Dope, Epoxy, and Resins 92
149. Blushing and Use of Blush-Retarding Thinner 92
150. Number of Coats . 92
151. Technique - 93
152. Rejuvenation of Fabric 93
153. Common Dope Troubles 94
154.-164. Reserved 94
AC 43.13-1A CHO 1 Page Hi 1975 TABLE OF CONTENTS-Continued Paragraph Page Section 3. REPAIRS TO FABRIC COVERING
105. General 95
166. Repair of Tears In Fabric 95
167. Sewed Patch Repair --- 96
168. Unsewed (Doped-On) Repairs 90
160. Repair by a Doped-In Panel 90
170.-180. Reserved 97 Section 4. FABRIC TESTING 181, Testing of Fabric Covering 98
182.-102. Reserved 98 Chapter 4. CONTROL CABLES AND TERMINALS Section 1. INSPECTION AND REPAIR
193. General
184. Cable Specifications
105. Replacement of Cables
190. Mechanically Fabricated Cable Assemblies
187. Hand Fabricated Cable Assembles
188. Cable System Inspection
199. Cable Tension Adjustment 110
200. Corrosion and Rust Prevention . 110
201.-211. Reserved 111 Section 2. SAFETY METHODS FOR TURNBUCKLES
212. General
213. Double Wrap Method
214. Single Wrap Method 114
215. Special Locking Devices 119
216.-226. Reserved 114 Chapter 5. AIRCRAFT HARDWARE Section 1. IDENTIFICATION AND USE OF AIRCRAFT HARDWARE
227. Bolta 115
228. Screws 117
229. Taper Pins (AN-385 and AN-386) - 119
230. Nuts 110
231. Washers - 120
292. Types of Rivets
233. Material Applications
284. Fasteners (Cowl and Fairing)
285. Unconventional Attachments
286.-248. Reserved 122 Chapter 6. CORROSION PROTECTION
247. Types of Corrosion
248. Corrosion Protection Measures for Basic Materials
249. Construction of Corrosion Resistant Structure
250. Corrosion Removal
251. Corrosion Proofing of Landplanes and Seaplanes 127
252. Corrosion Proofing of Landplanes Converted to Seaplanes 127
258. Cleaners, Polishes, Brighteners 128 * 255-284. Reserved 254. Handling and Care of Aircraft Recovered from Water Immersion 128 * 128-8
Page Iv AC 43.13-1A CHG 1 1975 TABLE OF CONTENTS--Continued Chapter 7. IDENTIFICATION, TESTING, AND INSPECTION
OF MATERIALS Paragraph Page Section 1. IDENTIFICATION OF METALS
265. IdentIfication of Steel Stock 129
208. Interchangeability of Steel Tubing - 120
287. Identification of Aluminum 120
288.-278. Reserved 181 Section 2. TESTING OF METALS
279. Hardness Testing 132
280. Brinell Hardness Test 132
281. Rockwell Hardness Test 182
282. Vickers Hardness Test 182
283. Testing Aluminum 182
284.-294. Reserved 132 Section 3. NONDESTRUCTIVE TESTING
205. General 186
206. Inspection by Magnifying Glass After Welding 136
207. Magnetic Particle Inspection 186
208. X-Ray or Radiographic Inspection 137
299. Fluorescent Penetrant 188
300. Dye Penetrants 188
801. Ultrasonle Flaw Detection 139
802.-312. Reserved 189 Section 4. IDENTIFICATION OF FABRICS AND PLASTICS
818. Identification of Fabric 140 *
814. Identification of Plastics 140
315.-320. Reserved 140 * Section 5. CABIN INTERIOR MATERIALS, FIRE PROTECTION QUALITIES
321. Requirements for Fire Protection 140-1
922.-325. Reserved 140-1* Chapter 8. AIRCRAFT EQUIPMENT Section 1. LANDING GEAR EQUIPMENT
926. General 141
927. Inspection 141
328. Cleaning and Lubricating 145
329. Emergency Systems 145
330. Special Inspections 145
381. Retraction Tests 145
332. Tires 145 * 383. Tire Slippage - 150
834. Tire Maintenance 150 *
385.-348. Reserved 150 Section 2. LIFE PRESERVERS AND LIFERAFTS
344. General 151
345. Inspection Procedure for Life Preservers 151
346. Repair of Life Preservers 151
847. Inspection Procedure for Liferafts 151
348. Repair of Liferafts 152
849.-359. Reserved 152
AC 43.13-1A CHG 1 Page iv- 1975 TABLE OF CONTENTS-Continued Paragraph Page Section 3. MISCELLANEOUS EQUIPMENT
360. Parachutes 153
361. Safety Belta 158
382. Flares 154
863. Oxygen Systems 151
364.-374. Reserved 158
AC 43.13-1A CHG 1 1975 all highly stressed main fittings, as set forth in Chapter 7, and if necessary, take corrosion prevention measures as recommended in Chapter 6.
(3) Replace torn, kinked, or cracked fittings.
(4) Elongated or worn boltholes in fittings which were designed without bushings are not to be reamed oversize. Replace such fittings, unless the method of repair is approved by a representative of the FAA. Do not fill holes with welding rod. Acceptable methods of repairing elongated or worn boltholes in landing gear, stabilizer, interplane, or cabane-strut ends only, not originally equipped with pin plates, are shown in figure 2.36. (Also see figure 2.11 on longeron repair at fitting.)
b. Aluminum and Aluminum Alloy Fittings.
(1) Replace damaged fittings with new parts, having the same material specifications.
(2) Repairs may be made in accordance with data furnished by the aircraft manufacturer or data substantiating the method of repair may be submitted to the FAA for review.
103. CASTINGS. Damaged castings are to be replaced and not repaired unless the method of repair is specifically approved by the aircraft manufacturer or substantiating data for the repair has been reviewed by the FAA.
* 104. SELECTIVE PLATING IN AIRCRAFT MAINTE- NANCE. Selective plating is a method of depositing metal from an electrolyte to the selected area. The electrolyte is held in an absorbent material attached to an inert anode. Plating contact is made by brushing or swabbing the part (cathode) with the electrolyte-bearing anode.
a. Selective Plating Uses. This process can be utilized for any of the following reasons:
(1) To prevent or minimize disassembly, reassembly, or masking costs.
(2) Resizing worn components (plate to size).
(3) Filling in damaged or corroded areas.
(4) To plate small areas of extremely large parts.
(5) To plate electrical contacts.
(6) To plate parts too large for existing baths.
Chap 2 Page 73
(7) To supplement conventional plating.
(8) To plate components which become contaminated if immersed in a plating bath.
(9) To cadmium-plate ultra high strength steels without hydrogen embrittlement.
(10) On-site plating.
111) Reverse current applications (e.g., stain removal, deburring, etching, dynamic balancing).
b. Specifications. Selective plating (electrodeposition), when properly applied, will meet the following specifications and standards:
QQ-C-320 Chromium Plating QQ-N-290 Nickel Plating QQ-P-416 Plating, Cadmium QQ-5-365 Silver Plating 22-1-325 Zinc Plating MIL-T-10727 Tin Plating MIL-C-14550 Copper Plating MIL-G-45204 Gold Plating
c. General Requirements.
(1) Areas to be repaired by this process should be limited to reasonably small areas of large parts, although it may be desirable to plate small parts, particularly electrical or electronic parts, in their entirety.
(2) All solutions should be kept clean and free from contamination. Care should be taken to insure that the solutions are not contaminated by used anodes or other plating solutions. Brush plating solutions are not designed to remove large amounts of scale, oil, or grease. Mechanical or chemical methods should be used to remove large amounts of scale or oxide. Use solvents to remove grease or oil.
(3) Brush plating solutions are five to fifty times as concentrated as tank solutions. The current densities used range from 500 to 4,000 amps/feet?. The voltages listed on the solution bottles have been precalculated to give proper current densities. Too high a current density burns the plating, while too low a current density produces stressed deposits and low efficiencies.
Agitation is provided by anode/cathode motion.
Too fast a motion results in low efficiencies and stressed deposits; too slow a motion causes burning. A dry tool results in burnt plate, coarse grain structure, and unsound deposits. The tool* Par 102
*cannot be too wel. Solution temperatures of 110° to 120° F. are reached during operation.
(4) Materials such as stainless steel, aluminum, chromium, and nickel, which have a passive surface, will require an activating operation to remove the passive surface, During the activating process, do not use solutions that have been previously used with reverse current because of solution contamination.
d. Equipment. The power source should operate on either 110 or 220 volt alternating current (AC), 60 Hertz, single phase input. It should have a capability to produce direct current having smooth characteristics with controlled ripple and be able to output a current of at least 25 amperes at 0 to 25 volts. Minimum instrumentation of the power source should include a voltmeter, ammeter, and ampere-hour meter.
(1) The ammeter should provide a full scale reading equal to the maximum capacity of the power source with an accuracy of +5 percent of the current being measured.
(2) The voltmeter should have sufficient capacity to provide a full scale reading equal to the maximum capacity of the power source and an accuracy of +1.0 volt.
(3) An ampere-hour meter should be readable to 0.001 ampere-hour and have an accuracy of 10.01 ampere-hour.
(4) The stylus should be designed for rapid cooling and to hold anodes of various sizes and configurations. For safety, the anode holder should be insulated.
(5) The containers for holding and catching runoff solutions should be designed to the proper configuration and be inert to the specific solution.
(6) The mechanical cleaning equipment and materials should be designed and selected to prevent contamination of the parts to be cleaned.
e. Materlals. The anodes should be of highpurity dense graphite or platinum-iridium alloys.
Do not mix solutions from different suppliers.
This could result in contamination.
f. Detail Requirements. On large parts, no area greater than approximately 10 percent of the total area of the part should be plated by this process. Small parts may be partially or completely plated. Special cases exceeding these Par 104 AC 43.13-1A CHG 1 1975 or oil.
Alloys.
(1) Electroclean the area using forward (direct) current until water does not break on the surface. This electroclean process should be accomplished at 10 to 15 volts, using the appropriate electroclean solution.
(2) Rinse the area in cold clean tap water.
(3) Activate the area with reverse current, 7 to 10 volts, in conjunction with the proper activating solution until a uniform gray to black surface is obtained.
(4) Rinse thoroughly in cold, clean tap water.
(5) Immediately electroplate to color while the area is still wet, using the appropriate nickel solution.
(6) Rinse thoroughly.
(7) Immediately continue plating with any other solution to desired thickness.
(8) Rinse and dry.
k. Plating on Copper and Copper Base Alloys.
(1) Electroclean the area using forward (direct) current until water does not break on the surface. The electroclean process should be accomplished at 8 to 12 volts using the appropriate electroclean solution. * Chap 2
AC 43.13-1A CHG 1 1975 * (2) Rinse the area in cold, clean tap water.
(3) Immediately electroplate the area with any of the plating solutions except silver. Silver requires an undercoat.
(4) Rinse and dry.
I. Plating on 300 and 400 Series Stainless Steels, Nickel Base Alloys, Chrome Base Alloys, High Nickel Ferrous Alloys, Cobalt Base Allays, Nickel Plate, and Chrome Plate.
(1) Electroclean the area using forward (direct) current until water does not break on the surface. This electroclean process should be accomplished at 12 to 20 volts using the appropriate electrocleaning solution.
(2) Rinse the aren in cold, clean tap water.
(3) Activate the surface using forward (direct) current for 1 to 2 minutes using the activating solution and accomplish at 6 to 20 volts.
(4) Do not rinse.
(5) Immediately nickel flash the surface to a thickness of 0.00005 to 0.0001 inch using the appropriate nickel solution.
(6) Rinse thoroughly.
(7) Immediately continue plating with any other solution to desired thickness.
(8) Rinse and dry.
m. Plating on Low-Carbon Steels (Heat Treated to 180,000 psi).
(1) Electroclean the area using forward Break an (direct) current until water does not break on the surface. This electroclean process should be accomplished at 12 to 20 volts using the appropriate electrocleaning solution.
(2) Rinse the area in cold, clean tap water.
(3) Reverse current etch at 8 to 10 volts, using the appropriate activating solution, until a uniform gray surface is obtained.
(4) Rinse thoroughly.
(5) Immediately electroplate the part using any solutions except copper acid or silver. Both these require undercoats.
(6) Rinse and dry.
n. Plating on Cast Iron and High-Carbon Steels (Steels Heat Treated to 180,000 psi).
(1) Electroclean the area using forward (direct) current until water does not break on Chap 2 Page 73-2 the surface. This electroclean process should be accomplished at 12 to 20 volts using the appropriate electrocleaning solution.
(2) Rinse the area thoroughly in cold, clean tap water.
(3) Reverse current etch at & to 10 volts, using the appropriate etching solution, until a uniform gray is obtained.
(4) Rinse thoroughly.
(5) Remove surface smut with 15 to 25 volts using the appropriate activating solution.
(6) Rinse thoroughly.
(7) Electroplate immediately using any of the solutions except copper or ailver (both these require undercoats).
(8) Rinse and dry.
o. Plating on Ultra High Strength Steels (Heat Treated Above 180,000 psi).
(1) Electroclean the area using REVERSE current until water does not break on the surface.
This electroclean process should be accomplished at 8 to 12 volts using the appropriate electroclean solution.
(2) Rinse the area thoroughly in cold, clean tap water.
(3) Immediately electroplate the part, using either nickel, chromium, gold, or cadmium. Other metals require an undercoat of one of the above.
Plate initially at the highest voltage recommended for the solution so as to develop an initial barrier layer. Then reduce to standard voltage.
(4) Rinse and dry.
(5) Bake the part for 4 hours at 375° +25° F.
NoTE 1: Where the solution vendor provides substantiating data that hydrogen embrittlement will not result from plating with a particular solution, then a post bake is not required. This substantlating data can be in the form of alrcraft industry manufacturers' process specifications, military specifications, or other sultable data.
NoTE 2: Acid etching should be avolded, if posible. Where etching is absolutely necessary, it should always be done with reverse current.
alkallne solutions for initial deposita.
p. Dissimilar Metals and Changing Base. As a general rule, when plating two dissimilar metals, follow the plating procedure for the one with the most steps or activation. If activating* Par 104
* steps have to be mixed, use reverse current activation steps prior to forward (direct) current activation steps.
q. Plating Solution Selection.
(l) Alkaline and neutral solutions are to be used on porous base metals, white metals, highstrength steel, and for improved coating ability.
Acid solutions are to be used for rapid buildup and as a laminating structure material in conjunction with alkaline type solutions.
(2) Chrome brush plating solutions do not yield as hard a deposit as bath plating solutions.
The hardness is about 600 Brinell as compared to 1,000 Brinell for hard chrome deposited from a tank.
(3) Silver immersion deposits will form with no current flowing on most base metals from the silver brush plating solutions; such deposits have poor adhesion to the base metal. Consequently, a flash or a more noble metal should be deposited prior to silver plating to develop a good bond.
(4) In general, brush plating gives less hydrogen embrittlement and a lower fatigue strength loss than does equivalent tank deposits.
However, all brush-plated, ultra high strength steel parts (heat treated above 180,000 psi) Par 104 AC 43.13-1A CHG 1 1975 should be baked as mentioned in paragraph
104.0.(5), unless it is specifically known that embrittlement is not a factor.
r. Qualification Tests. All brush plated surfaces shall be tested for adhesion of the electrodeposit. Apply a 1-inch wide strip of Minnesota Mining and Manufacturing tape code 250, or an approved equal, with the adhesive side to the freshly plated surface. Apply the tape with heavy hand pressure and remove it with one quick motion perpendicular to the plated surface. Any plating adhering to the tape shall be cause for rejection.
s. Personnel Training for Quality Control.
Manufacturers of selective plating equipment provide training in application techniques at their facilities. Personnel performing selective plating must have adequate knowledge of the methods, techniques, and practices involved.
These personnel should be products of those training programs and certified as qualifed operators by the manufacturers of the products used, as well as by local quality control depart* ments.
105.-114. RESERVED.
Chap 2
AC 43.13-1A CHG 1 Page 73-4 1975