Airframe Or. Ch. 5 - Aircraft Fabric Covering
What is a tie-off knot?
A Standard, Modified Sieine Knot used on All stitches Except the Starting stitch
What is the principle advantage of the envelope method for covering wings?
Almost All the Seams are Machine-Sewed by the Envelope Supplier
How would you determine the correct spacing for rib stitching if the original spacing was unknown?
Consult the Chart in AC 43.13-1B
What two types of organic fibers are used for covering aircraft?
Cotton & Linen
How would you determine the strength requirements for fabric used to re-cover an aircraft?
Fabric must be of at least the Quality & Strength of the Original used the manufacturer
Which of the several types of fabric is unaffected by moisture and mildew?
Fiberglass
What type of synthetic fibers are used for covering aircraft?
Fiberglass & Heat-Shrinkable Polyester
Fabric is considered unairworthy when it has deteriorated to what percentage of its original strength?
Less than 70%
Aircraft coverings are made of materials from what two sources?
Organics & Synthetics
How are the fabric type and strength requirements determined for fabric-covered aircraft?
Original manufacturer determines the Fabric Type, & Strength requirements are a Function of the Never-Exceed Speed & Wing Loading
Where would you use surface tape?
Over Rib Stitching or Sewed Seams, Over Lapped Edges, Around Corners & Along Leading & Trailing Edges
Name three common types of machine-sewed seams
Plain Overlap, Folded-Fell & French-Fell
How should the edges of drainage, inspection and ventilation holes be reinforced?
Plastic, Aluminum or Brass Grommets
What is the purpose of the salvage edge on a roll of fabric?
Prevents the Fabric from Unraveling
What are the principle methods used to test the condition of fabric?
Punch Testers (Maule or Seybolt Tester) & Laboratory Pull-Testing
What identification markings is found on the salvage edge, and in which direction is the warp applied?
The FAA-PMA Stamp is found on the Selvage Edge & Warp is Parallel to the Line of Flight
How should a structure that will be covered with doped fabric be prepared following inspection and prior to covering?
Treat it with a Protective Coating of Paint or Varnish as appropriate
Where are anti-tear strips used?
Under Wing Rib Stitching when the Vne is greater than 250 mph
What is the function or purpose of reinforcing tape?
Used between the Fabric & Rib Stitching to prevent the Lacing Cord from Cutting through the fabric
What is meant by the warp, weft and bias?
*Warp is the direction along the Lenght of the fabric, *Weft is the direction Across, Right Angle to the warp & *Bias is the direction at 45 Degree Angle to the warp
