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A&P Airframe oral: free sample

10 oral questions from across the Airframe subjects. Say each answer out loud, reveal the model answer, and tick the key points you hit. The real oral is closed book and needs 70% of the whole section.

questions
10
questions
book, like the real oral
Closed
book, like the real oral
to pass the real oral
70%
to pass the real oral

Free practical project guide

Determine applicability of sheet metal for a repair in a specific application.

Metallic Structures · AM.II.A.S3 · paper task

What you are likely to be given

A damaged part or a description of one, several pieces of aluminum stock with their markings, the aircraft's structural repair manual or maintenance manual, and AC 43.13-1B.

The standard to meet

The original material is identified (alloy, temper, thickness, clad or bare) and the chosen sheet is equal to it in strength and suited to the forming the part needs, based on the manufacturer's data. Any substitution follows the manual's substitution data and is recognized as a major repair.

Steps

  1. 1Find the original material in the manual or parts data, then read the markings on the stock: specification number, temper or condition, or commercial code, printed in rows about 5 inches apart on sheet.
  2. 2Interpret the alloy: for example 2024 for structures and skins, 1100 and 3003 where strength is not important, 5052 where workability and corrosion resistance are needed.
  3. 3Start from the rule that replacement sheet must be identical to the original or properly altered skin.
  4. 4If a substitute is needed, use the SRM substitution data. A weaker alloy needs a heavier gauge; a stronger but thinner sheet cannot be substituted.
  5. 5Match the temper to the forming. Heat-treated and cold-worked alloys stand very little bending; a severely formed part is made from soft, annealed sheet and heat-treated after forming, per the manufacturer's instructions.
  6. 6Annealed alloy is not recommended for a structural repair; an equivalent strength repair in annealed alloy weighs more than one in heat-treated alloy (AC 43.13-1B para 4-53b, p. 4-15).
  7. 7Use clad material for parts that will be left unpainted, and reject any sheet with cracks, scratches, kinks, tool marks or corrosion pits.
  8. 8State that a repair involving substitution of material is an airframe major repair.

Where to look

  • AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-29 to 4-30 (aluminum markings and typical uses)
  • AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-86 and 4-92 (maintaining strength, substitution, repair material selection)
  • AC 43.13-1B CHG 1, para 4-53 (p. 4-15) (selection of aluminum for replacement parts)
  • 14 CFR part 43, appendix A, para (b)(1)(xxi) (substitution of material is a major repair)
  • The manufacturer's structural repair manual: original material callout and material substitution table

Safety

  • Do not apply local heating to help bend, flatten or expand heat-treated aluminum alloy; temperature is hard to control and it may damage the metal and impair its corrosion resistance.

Common mistakes that fail the project

  • Substituting a thinner sheet of a stronger alloy.
  • Using a soft alloy for primary structure because it is easy to form.
  • Choosing a hard temper for a part with tight bends, so it cracks when formed.
  • Using bare sheet on a part that will be left unpainted.

Practice questions

Like the two questions the examiner asks during each project. The practical is open book, so knowing where to look counts.

Q1. The only alloy available is weaker than the original. What must you do?Reveal

Use a heavier gauge to give equivalent cross-sectional strength. A lighter gauge should not be used even when using a stronger alloy.

AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-92

Q2. Where would you find which material may be substituted and how much thicker it must be?Reveal

In the manufacturer's SRM, which often shows what material can be substituted and how much thicker it must be, for example in a material substitution table.

AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-86

Q3. How is aluminum sheet marked so you can identify it?Reveal

With symbols such as a government specification number, the temper or condition furnished, or the commercial code marking. Plate and sheet are marked in rows about 5 inches apart.

AC 43.13-1B CHG 1, para 4-4 (p. 4-3)

FAA sources

  • AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-29 to 4-30
  • AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-86
  • AMT Airframe (FAA-H-8083-31B), ch. 4, p. 4-92
  • AC 43.13-1B CHG 1, para 4-4 (p. 4-3)
  • AC 43.13-1B CHG 1, para 4-53 (p. 4-15)
  • AC 43.13-1B CHG 1, para 4-54 (p. 4-16)
  • AC 43.13-1B CHG 1, para 4-58 (p. 4-43)
  • 14 CFR part 43, appendix A, para (b)(1)(xxi)