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Splayed patch hole size limit

Aviation Mechanic Airframe (AMA) practice question 3 of 30 on Non-Metallic Structures. ACS element AM.II.B.K6 · difficulty: applied. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONA splayed patch is planned in plywood skin that is one-tenth inch thick. What is the largest trimmed hole dimension for which this repair may be used?

  1. A0.5 inch, or 5 times the skin thickness
  2. B1.5 inches, or 15 times the skin thickness
  3. C15 inches, which is 150 times the skin thickness
Show the answer and explanation

Correct answer: B. 1.5 inches, or 15 times the skin thickness

  • A — incorrect The 5:1 figure is the taper cut on the edges of the patch, not the limit on hole size.
  • B — correct The splayed patch is limited to holes whose largest dimension is not more than 15 times the skin thickness, and 15 times one-tenth inch is 1.5 inches.
  • C — incorrect This multiplies the thickness by the wrong factor; the limit is 15 times the thickness, not 150 times.

BACKGROUND

A splayed patch is a flush repair for plywood skin in which the edges of the patch are tapered at a 5:1 ratio to the skin thickness. The handbook restricts it to small holes whose largest dimension is not more than 15 times the skin thickness, and to skin no more than one-tenth inch thick. Working the sample numbers gives nothing larger than a 1.5-inch trimmed hole in very thin plywood. The patch is made from the same type and thickness of plywood as the surface being repaired, with its grain parallel to the original skin. A pressure plate cut to the exact size of the patch, with waxed paper between, holds it while the glue sets.

STUDY TIP

Keep the two ratios separate in your mind: 5:1 is the edge taper of a splayed patch, while 15 times the skin thickness is the hole size limit.

KEY POINTS

  • Splayed patch hole limit is 15 times the skin thickness.
  • Skin must be no more than one-tenth inch thick.
  • The patch edges are tapered at a 5:1 ratio.

SOURCES

  • FAA-H-8083-31B ch06 "Splayed Patch"
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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.