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Patch material gauge for riveted repairs

Aviation Mechanic Airframe (AMA) practice question 12 of 20 on Metallic Structures. ACS element AM.II.A.K2 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONFor internal riveted and bolted repairs, what splice or patch material is normally used?

  1. ASame type of material at half the gauge
  2. BSame type of material, one gauge heavier
  3. CA stronger alloy in a thinner gauge, tapered
Show the answer and explanation

Correct answer: B. Same type of material, one gauge heavier

  • A — incorrect Reducing the thickness would leave the splice with less cross-sectional area than the part it bridges, so the original strength could not be restored.
  • B — correct The handbook specifies that splice members in internal riveted and bolted repairs are normally the same type of material as the damaged part, but one gauge heavier.
  • C — incorrect A material that is stronger but thinner cannot be substituted, because buckling and torsional strength depend chiefly on thickness rather than on allowable compressive and shear strength.

BACKGROUND

Damage that exceeds negligible limits but is not too extensive to bridge is classed as damage repairable by patching. The splice members are designed to span the damaged area and overlap the surrounding undamaged structure, and structural fasteners tie them to the original members so the load path is restored. For internal riveted and bolted repairs, the splice or patch is normally the same type of material as the damaged part but one gauge heavier. Filler plates of the same gauge and type as the damaged component may also be used for bearing purposes or to bring the part back to its original contour. The broader rule behind this is that replacement material must be similar to the original, and if a weaker alloy has to be substituted, a heavier thickness must be used to give equivalent cross-sectional strength.

STUDY TIP

Remember the pair of rules together: weaker alloy means heavier gauge, and a stronger but thinner material is never an acceptable substitute.

KEY POINTS

  • Internal riveted and bolted splice material is normally the same type as the damaged part, one gauge heavier.
  • Filler plates may be the same gauge and type, used for bearing or to restore contour.
  • A stronger but thinner material cannot be substituted, because thickness drives buckling and torsional strength.

SOURCES

  • sources/ama-airframe/ch04.txt "Damage Repairable by Patching"
  • sources/ama-airframe/ch04.txt "Maintaining Original Strength"
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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.