Aircraft Coverings

Question 1

1. What determines the required quality & strength of fabric that is to be used for covering aircraft?

Answer 1

Determined by pound per square foot of wing loading (PSF) & the never exceed speed of the aircraft (VNE)

Question 2

2. When are anti-tear strips recommended & where are they used?

Answer 2

Under wing rib stitching when VNE is greater than 250

Question 3

3. What is the maximum permissible deterioration of aircraft fabric before it is considered unairworthy?

Answer 3

More than 30% from original tensile strength

Question 4

4. What should be the strength of the fabric used for re-covering an aircraft?

Answer 4

High grade aircraft tensile material, equivalent to the original strength from original manufacturer

Question 5

5. What is the purpose & location of drain grommets in aircraft fabric?

Answer 5

Allows condensed moisture to leave the aircraft as well as ventilation
located underside of airfoils trailing edge close to ribs

Question 6

6. How are drain grommets installed in aircraft fabric?

Answer 6

Brass grommets mounted to fabric patches then doped to coverings
Plastic grommets are doped directly to coverings
Both require 2nd coat of dope

Question 7

7. Name the methods of applying fabric to an aircraft wing?

Answer 7

Blanket & envelope method

Question 8

8. What is the purpose of reinforcing tape?

Answer 8

Used under all stitching, prevents stitching ford from tearing through fabric

Question 9

9. What type of fabric is not affected by moisture or mildew?

Answer 9

Fiberglass

Question 10

10. What methods are used to check the strength of doped fabric?

Answer 10

Fabric punch test if fails then a laboratory test

Question 11

11. What type of machine-sewed seems are used in aircraft coverings?

Answer 11

Plain overlap seams
Folded fell seams
French fell seams

Question 12

12. What should be done with structure that will come in contact with doped fabric?

Answer 12

Treat all parts of the structure

Question 13

13. If the original rib stitch spacing cannot be determined when re-covering and aircraft, where can you find the rib stitch spacing that should be used?

Answer 13

AC 43.13B

Question 14

14. What is the standard tie off knot used during rib stitching?

Answer 14

Modified seine knot

Question 15

15. What do you call the edge cloth, tape, or webbing that has been woven to prevent raveling?

Answer 15

Selvage edge

Question 16

16. The type of fabric used for covering aircraft are organic & synthetic. Name two organic and two synthetic types.

Answer 16

Organic fibers - cotton & linen

Synthetic fibers - fiberglass & nylon

Question 17

17. When covering aircraft, where is surface tape used?

Answer 17

Sewed seams, lapped edges, & all stitching

Question 18

18. Name the advantages of using the envelope method to cover fabric aircraft.

Answer 18

Saves labor most sewing is done by machine

Question 19

19. How are wrinkles removed from cotton fabric?

Answer 19

Wetting the wrinkles & allowing to dry

Question 20

20. When is finishing tape applied?

Answer 20

After the second coat of dope is dry, and the nap has been sanded away

Question 21

21. How wide should surface tape be when used to cover the trailering edge of an aircraft wing?

Answer 21

Three inches

Question 22

22. What is the recommended type of repair for an L shaped tear when the legs are more than 14 inches long?

Answer 22

A doped on patch, if VNE is less than 150mph