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How polyester fabric repairs are made

Aviation Mechanic Airframe (AMA) practice question 24 of 30 on Non-Metallic Structures. ACS element AM.II.B.K17 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONAccording to the instructions issued with supplemental type certificates, how are nearly all repairs to polyester aircraft covering made?

  1. ABy machine sewing the patch on
  2. BBy hand sewing four stitches per inch
  3. CBy cementing the patch
Show the answer and explanation

Correct answer: C. By cementing the patch

  • A — incorrect Nearly all polyester repairs are made without sewing, and machine sewing of polyester is rare and mostly limited to making prefitted envelopes.
  • B — incorrect Sewing techniques from AC 43.13-1 were developed primarily for cotton and linen fabrics, not for routine polyester repairs.
  • C — correct Supplemental type certificate instructions for polyester fabric call for cemented repairs, which most technicians prefer as easier than sewn repairs.

BACKGROUND

The type of repair performed depends on the extent of the damage and the process under which the fabric was installed, and the approved data used for the covering job is the same approved data used for the repair. While many cotton fabric repairs involve sewing, nearly all repairs of polyester fabric are made without sewing. Sewing techniques from AC 43.13-1 can be applied to polyester, but they were developed primarily for cotton and linen. Supplemental type certificate instructions for polyester fabric describe cemented repairs, which most technicians prefer. There is no compromise to the strength of the fabric with either method.

STUDY TIP

Before touching a damaged covering, find the logbook entry that identifies the approved data used to install it, because a patch technique valid for one system can make the aircraft unairworthy on another.

KEY POINTS

  • Polyester fabric repairs are normally cemented rather than sewn.
  • The approved data used for the covering governs the repair.
  • Neither the sewn nor the cemented method compromises fabric strength.

SOURCES

  • ama-airframe/ch03.txt "Repair Considerations"
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MORE ON NON-METALLIC STRUCTURES

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.