AIRCRAFT COVERINGS

Question 1

What two types of fabric are used for covering aircraft?

Answer 1

Organic and Polyester synthetic.

Question 2

What are the organic fibers used for covering aircraft?

Answer 2

Cotton and Linen.

Question 3

What is the fabric warp?

Answer 3

The direction along the length of fabric.

Question 4

What is a fabric selvage edge?

Answer 4

An edge of cloth woven to prevent unraveling.

Question 5

What is the purpose of reinforcing tape?

Answer 5

To protect and strengthen the area for attaching the fabric to the ribs or rib caps.

Question 6

How are ventilation and drainage hole edges reinforced?

Answer 6

With plastic or aluminum grommets.

Question 7

Who determines the quality and strength requirements for a fabric-covered aircraft?

Answer 7

The original manufacturer by the never-exceed speed and wing loading.

Question 8

What % is the maximum permissible deterioration in fabrics?

Answer 8

30% of the original fabric strength.

Question 9

What methods are used to check the condition of fabric?

Answer 9

A test strip or punch tester. When results are marginal, a laboratory test is needed.

Question 10

What is one advantage of the envelope method of covering wings?

Answer 10

Use of precut and pre-sewn envelopes.

Question 11

When using the envelope method, the envelopes must be sewn with what?

Answer 11

Approved machine sewing thread, edge distances, fabric fold, etc. such as those specified in AC43.131b; or, envelopes are slid into position, oriented with the seams in the proper place.

Question 12

What is done to a structure to be covered with doped fabric?

Answer 12

Cover sharp edges, metal seams, rivets heads with anti-chafe tape. Apply a protective coating of an approved primer, or varnish if it is a wood.

Question 13

What is a tie-off knot?

Answer 13

A modified seine. Normally used on all stitches other than the starting stitch.

Question 14

What rib lace spacing reference is use when the original spacing is unknown?

Answer 14

Use the chart in AC 43.13-18

Question 15

How would you determine the strength requirements for fabric used to re-cover an aircraft?

Answer 15

The fabric must be of at least the quality and strength of the fabric used by the original manufacturer.

Question 16

What is meant by warp, weft, and bias?

Answer 16

Warp is the direction along the length of fabric, waft is the direction across the fabric at right angles to the warp, and a bias is a direction at a 45-degree angle to the warp and weft.

Question 17

What identification marking is found on the selvage edge, and in which direction is the warp applied?

Answer 17

The FAA-PMA stamp is found on the selvage edge and the warp is applied parallel to the line of flight.

Question 18

What types of synthetic fibers are used for covering aircraft?

Answer 18

Fiberglass and heat-shrinkable polyester fibers.

Question 19

Which of the several types of fabric is unaffected by moisture and mildew?

Answer 19

Fiberglass.

Question 20

Where would you use surface tape?

Answer 20

Over rib stitching and sewed seams, over lapped edges, around corners, and along leading and trailing edges.

Question 21

How should a structure that will be covered with doped fabric be prepared following inspection and prior to covering?

Answer 21

Treat it with a protective coating of paint or varnish as appropriate.

Question 22

Name three common types of machine-sewed seams.

Answer 22

Plain overlap, folded-fell, and french-fell.

Question 23

Where are anti-tear strips used?

Answer 23

Under wing rib stitching when the never-exceed speed is greater than 250 mph.