Aircraft Coverings

What two types of fabric are used for covering aircraft?

Organic and polyester synthetic.

What are the organic fibers used for covering aircraft?

Cotton and linen.

What is the fabric warp?

The direction along the length of fabric.

What is a fabric selvage edge?

An edge of cloth woven to prevent unraveling.

What is the purpose of reinforcing tape?

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

How are ventilation and drainage hole edges reinforced?

With plastic or aluminum grommets.

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

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

What % is the maximum permissible deterioration in fabrics?

30% of the original fabric strength.

What methods are used to check the condition of doped fabric?

A test strip or punch tester; a laboratory test is needed for marginal results.

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

Use of precut and pre-sewn envelopes.

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

Approved machine sewing thread.

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

Cover sharp edges, metal seams, rivet heads with anti-chafe tape and apply a protective coating of primer or varnish.

What is a tie-off knot?

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

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

Use the chart in AC 43,13-18.

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

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

What is meant by warp, weft, and bias?

Warp is the length direction, weft is the width direction, and bias is a direction at a 45-degree angle to both.

What identification marking is found on the selvage edge?

The FAA-PMA stamp.

What types of synthetic fibers are used for covering aircraft?

Fiberglass and heat-shrinkable polyester fibers.

Which type of fabric is unaffected by moisture and mildew?

Fiberglass.

Where would you use surface tape?

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

How should a structure be prepared before covering with doped fabric?

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

Name three common types of machine-sewed seams.

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

Where are anti-tear strips used?

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