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Bolted repairs in honeycomb sandwich

Aviation Mechanic Airframe (AMA) practice question 26 of 30 on Non-Metallic Structures. ACS element AM.II.B.K22 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONWhy are bolted repairs prohibited in composite honeycomb sandwich assemblies?

  1. AFasteners cannot be torqued to the correct value
  2. BFastener holes allow moisture to enter the core
  3. CThe core cannot be sanded to a proper scarf angle
Show the answer and explanation

Correct answer: B. Fastener holes allow moisture to enter the core

  • A — incorrect Torque is not the stated reason; the prohibition rests on moisture entering through the holes.
  • B — correct The handbook prohibits bolted repairs in honeycomb sandwich assemblies because of the potential for moisture intrusion through the fastener holes.
  • C — incorrect Scarf sanding is part of the preferred bonded repair for sandwich parts, not the reason bolted repairs are prohibited.

BACKGROUND

Bolted and bonded repairs each have a place in composite work. Bonded repairs avoid the stress concentrations created by drilling fastener holes and can be stronger than the original material, but the repair materials require special storage, handling, and curing. Bolted repairs are quicker and easier to fabricate and are normally used on composite skins thicker than 0.125 inch so that enough fastener bearing area is available for load transfer. They are prohibited in honeycomb sandwich assemblies because of the potential for moisture intrusion through the fastener holes. Honeycomb sandwich parts with thin face sheets are most effectively repaired with a bonded scarf type repair.

STUDY TIP

Remember the thickness rule of thumb for bolted repairs and the specific reason they are ruled out for sandwich structure.

KEY POINTS

  • Bolted repairs are prohibited in honeycomb sandwich assemblies.
  • The reason is moisture intrusion through fastener holes.
  • Bolted repairs are normally used on skins thicker than 0.125 inch.

SOURCES

  • FAA-H-8083-31B ch07 "Bonded versus Bolted Repairs"
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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.