Answers - Aircraft Fabric covering

Fill in the Blanks

1. Cotton, sag, doping or nitrate doping
2. 5‐10
3. Polyester
4. Pinking shears, unraveling
5. Unairworthy
6. One‐time
7. UV light
8. Retarder
9. Fasteners, airflow
10. Organic
11. Weight, stresses
12. Rejuvenator, airworthy
13. Exposed, 1.25 or 1 ¼”
14. Blanket, precut or pre‐sewn
15. Temperature, humidity
16. Volume, pressure
17. Durability, appearance
18. Propeller wash, one rib
19. Inspection or maintenance, inspection
20. Patches, strut

True or False

1. false; along the length of fabric
2. true
3. false; FAA issued
4. true
5. false; different thread
6. true
7. true
8. true
9. false; all coatings should be removed
10. false; not an FAA approved method
11. true
12. true
13. true
14. true
15. false; dope or glue
16. true
17. false skipping from one end to the other and the middle
18. true
19. false; the widest ‐ 4”
20. true

Knowledge Application

1. They created a system of combining nitrate dope and butyrate dope. The fabric was first coated with nitrate dope for adhesion and protective qualities and then butyrate dope was added reducing the overall flammability.

2. Appendix A states that changing parts of an aircraft wing, tail surface, or fuselage when not listed in the aircraft specifications issued by the FAA is a major alteration and requires a Form 337.

3. It is a self‐adhesive cloth tape that is used on sharp protrusions, rib caps, metal seams, and other areas to provide a smoother surface to keep fabric from being torn.

4. Hand thread is 3‐ply, uncoated polyester thread with a 15‐lb tensile strength; machine thread is 4‐ply with a 10‐lb tensile strength.

5. With a hot soldering pencil that also heat seals the fabric through the center of the fabric.

6. The blanket method uses multiple flat sections of fabric trimmed and attached to the airframe. Each aircraft is considered differently to determine size and layout of the blankets but it is typical for a small blanket to be cut for each small surface. Fabric is adhered to the airframe using approved adhesive, and specific manufacturer’s instructions.

7. Eye protection, respirator, skin protection, and ventilation.

8. A sheet of felt or polyester padding may be used before the fabric is applied. Approved padding ensures compatibility with the adhesives and first coating of the covering process.

9. Fabrics is shrunk in stages, using lower temperature first. The first shrink removes wrinkles and excess fabric. The final shrinkage gives the desired tautness. Fabric should be shrunk by skipping from one end to the other and then the middle to achieve uniform tautness.

10. Drain grommets allows for an escape of rain water and condensation from under the fabric. They are located at the lowest part of each structural area and each rib bay of the wings. Specific locations of each drain grommet can be found in the AC 43.13 or STC.

11. Chordwise tape is applied first followed by spanwise tape.

12. It is a coat used in some approved covering processes that combines the sealer and fill coats into one. They surround and seal the fabric fibers, provide a good adhesion for following coats, and have UV blocking agents.

Multiple Choice

1. c
A cut, fold, or seam made diagonally to the warp or fill threads.

2. a
Title 14 of the Code of Federal Regulations (14 CFR) part 43, Appendix A, states which maintenance actions are considered major repairs and which actions are considered major alterations.

3. c
FAA Form 337, which satisfies the documentation requirements for major fabric repairs and alterations, requires participation of an FAA-certificated Airframe and Powerplant (A&P) mechanic with an Inspection Authorization (IA) in the re-covering process.

4. b
Reinforcing tape is most commonly used on rib caps after the fabric covering is installed to protect and strengthen the area for attaching the fabric to the ribs.

5. c
Grommets are used to create reinforced drain holes in the aircraft fabric. Usually made of aluminum or plastic, they are glued or doped into place on the fabric surface.

6. a
Fabric primer is a coating used in some approved covering processes that combines the sealer and fill coatings into one. Applied to fabric after the finishing tapes are installed, these fabric primers surround and seal the fabric fibers, provide good adhesion for all of the following coatings, and contain UV blocking agents. One modern primer contains carbon solids and others use chemicals that work similarly to sun block for human skin.

7. a
An accelerators contains solvents that speed up the drying time of the product with which it is mixed. It is typically used when the application working temperature is below that of the ideal working temperature. It can also be used for faster drying when airborne contaminants threaten a coating finish.

8. b
Vinyl is the key ingredient in the popular Poly-Fiber covering system.

9. a
On aircraft with wing loading of 9 pounds per square foot and over, or a VNE of 160 miles per hour (mph) or higher, fabric equaling or exceeding the strength of Grade A cotton is required.

10. c
For aircraft with wing loading less than 8 pounds per square foot or less, or VNE of 135 mph or less, the fabric is considered unairworthy when the breaking strength has deteriorated to below 35 pounds (new minimum strength of 50 pounds).

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