Aircraft Covering

Question 0

What paperwork must be completed if an aircraft that was originally covered with Grade-A cotton fabric is re-covered using a synthetic fabric?

Answer 0

The covering must be done according to a Supplemental Type Certificate, and a Form 337 must be executed, stating that all materials and processes complied with the requirements of the STC.

Question 1

What are three types of fabric that can be used to cover an aircraft?

Answer 1

Cotton fabric, synthetic fabric, and glass fabric.

Question 2

What type of rib lacing cord is recommended for attaching cotton fabric to an aircraft structure?

Answer 2

Waxed linen cord.

Question 3

How wide should the surface tape be that is used to cover the trailing edge of an aircraft wing?

Answer 3

Three inches wide.

Question 4

Why is the surface tape used on the trailing edge of the control surfaces of some airplanes notched?

Answer 4

Since the edges of this tape face into the wind, it is possible that it could start to lift and form a very effective spoiler. If the tape is notched, it will tear off at a notch.

Question 5

What is the purpose of the reinforcing tape that is used between the fabric and the rib lacing on an aircraft wing?

Answer 5

The reinforcing tape keeps the rib lacing cord from pulling through the fabric.

Question 6

Should a sewed seam in the fabric used to cover an aircraft wing run spanwise or chordwise?

Answer 6

Both spanwise and chordwise seams are permissible, but chordwise seams are preferred.

Question 7

What is the preferred seam used for machine-sewing pieces of aircraft fabric together?

Answer 7

The French fell seam.

Question 8

What type of material is used for inter-rib bracing in a fabric-covered aircraft wing?

Answer 8

Cotton reinforcing tape.

Question 9

What type of knot is used for locking the stitches that are used for rib lacing on a fabric-covered aircraft wing?

Answer 9

A modified seine knot.

Question 10

What determines the spacing of the rib lacing stitches on a fabric-covered aircraft wing?

Answer 10

The never-exceed speed of the aircraft.

Question 11

When is the finishing tape applied to a fabric-covered aircraft wing when it is being recovered?

Answer 11

After the second coat of dope has dried and the nap of the fabric has been sanded off.

Question 12

What is the recommended type of repair to a fabric-covered aircraft surface when it has an L-shaped tear with each of the legs of the tear more than 14 inches long?

Answer 12

If the never-exceed speed of the aircraft is less than 150 miles per hour, a doped-on repair can be made.

Question 13

What type of hand-sewing stitch is used when sewing in a panel of new fabric on an aircraft fabric-covered wing?

Answer 13

A baseball stitch, locked every eight to ten stitches.

Question 14

What is the minimum strength to which aircraft fabric is allowed to deteriorate before it is considered to be unairworthy?

Answer 14

Fabric can deteriorate to 70% of the strength of the fabric that is required for the aircraft.

Question 15

What is an antitear strip, and when are they required on a fabric-covered aircraft?

Answer 15

An antitear strip is a strip of the same type of fabric as is used for covering the wings. It is laid over the rib between the reinforcing tape and the fabric. An antitear strip is required for aircraft that have a never-exceed speed in excess of 250 miles per hour.

Question 16

When are drainage grommets applied when an aircraft is being re-covered?

Answer 16

They are laid into the third coat of dope, at the same time the surface tape is applied.

Question 17

Where are drainage grommets located on a fabric-covered aircraft wing?

Answer 17

At the lowest point in each bay. It is customary to install a grommet on each side of a wing rib, on the underside of the wing, at the trailing edge.

Question 18

How is the strength of the fabric on an aircraft structure determined?

Answer 18

An approximate strength test can be made with an FAA-approved fabric punch tester, but the only way to know for sure that the fabric has sufficient strength is by pull-testing a one-inch-wide sample of the fabric.

Question 19

Why are some portions of the structure of an aircraft dope proofed before they are covered with fabric?

Answer 19

Dope proofing keeps the fabric from sticking to the structure when the first coat of dope is applied. The fabric normally sags enough to touch the structure before it begins to pull taut.

Question 20

What is done to cotton and linen fabric to protect it from mildew?

Answer 20

The first coat of dope that is used on cotton and linen fabric has a mildewcide mixed in it.

Question 21

How is polyester synthetic fabric shrunk on an aircraft structure?

Answer 21

It is shrunk with heat from an iron or from a heated blower.

Question 22

What reference material may be used for acceptable covering methods for fabric-covered aircraft structure?

Answer 22

AC 43.13-1B, Chapter 2.

Question 23

What is meant by the selvage edge of a piece of fabric?

Answer 23

It is the woven edge of fabric used to prevent the material unraveling during normal handling.

Question 24

What are two methods of applying the fabric to the wing of an airplane?

Answer 24

The blanket method and the envelope method.

Question 25

What material is used to cover the overlapping edges of the leading edge metal to protect the fabric?

Answer 25

Cloth tape.

Question 26

What are two methods of attaching the fabric to the aircraft structure?

Answer 26

By sewing and with a cement.

Question 27

How are the wrinkles pulled out of cotton fabric?

Answer 27

Wet the cotton with water and allow it to dry.

Question 28

How is polyester fabric shrunk on the aircraft structure?

Answer 28

With heat from an iron.

Question 29

Organic fabrics include;

Answer 29

Cotton and linen.

Question 30

Synthetic fabrics include;

Answer 30

Fiberglass and heat shrinkable synthetics (Nylon, Orlon, Dacron).

Question 31

What determines the quality of fabric and strength requirements?

Answer 31

VNE and loading.

Question 32

Types of machine-sewn seams include;

Answer 32

French-fell, folded-fell, and plain overlap.

Question 33

Where is surface tape used?

Answer 33

Sewed seams, lapped edges, ribbed stitching and screws.

Question 34

What is the advantage of the envelope method of covering?

Answer 34

Most sewing is done by machines.

Question 35

How are vent and drain holes reinforced?

Answer 35

Plastic, aluminum, or brass grommets.

Question 36

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

Answer 36

Fiberglass.

Question 37

What rib lacing spacing is used when original is not known?

Answer 37

Chart AC 43.13-1B

Question 38

In what direction is the warp and selvage applied?

Answer 38

Parallel to flight TSO # on selvage edge.