Airframe Mechanic Certification Aircraft Structures 3 — Questions and Answers
Question 1: Which type of wing construction uses the skin as the primary load-carrying element with minimal internal framework?
- Truss-type
- Multi-spar
- Monocoque (Correct answer)
- Warren truss
Correct answer: Monocoque
Monocoque construction relies on the outer skin to carry all or most structural loads, with minimal internal supporting structure.
Question 2: What effect does cold working (such as shot peening) have on aluminum aircraft structure?
- Reduces hardness to allow easier forming
- Introduces compressive residual stress to improve fatigue life (Correct answer)
- Increases susceptibility to stress corrosion cracking
- Removes work-hardening from the surface layer
Correct answer: Introduces compressive residual stress to improve fatigue life
Shot peening induces compressive residual stresses in the surface layer, which counteract tensile fatigue stresses and significantly extend component life.
Question 3: What is the purpose of a fail-safe design philosophy in aircraft structure?
- Prevent any crack from forming in the structure
- Ensure the structure can sustain loads after partial failure until detected (Correct answer)
- Eliminate the need for scheduled structural inspections
- Guarantee that no structural failure will ever occur
Correct answer: Ensure the structure can sustain loads after partial failure until detected
Fail-safe design ensures that if one structural element fails, remaining elements carry loads safely until the damage is found during routine inspection.
Question 4: When inspecting a tubular steel fuselage truss, which type of damage is most critical to detect at weld joints?
- Surface oxidation
- Paint delamination
- Cracks or porosity (Correct answer)
- Thermal discoloration
Correct answer: Cracks or porosity
Cracks and porosity at weld joints represent structural discontinuities that can propagate under cyclic loads and lead to sudden failure.
Question 5: What is the term for the tendency of a long, slender column to buckle sideways when subjected to compressive loads?
- Creep
- Euler buckling (Correct answer)
- Stress relaxation
- Plastic deformation
Correct answer: Euler buckling
Euler buckling describes the instability of a slender column under axial compression, where it deflects laterally rather than compressing uniformly.
Question 6: Clad aluminum (Alclad) is used in aircraft skin panels primarily to:
- Increase tensile strength beyond standard aluminum
- Provide a pure aluminum coating that protects against corrosion (Correct answer)
- Allow dissimilar metal joining without galvanic corrosion
- Reduce the weight of structural panels
Correct answer: Provide a pure aluminum coating that protects against corrosion
Alclad has a thin layer of pure aluminum bonded to high-strength alloy, providing galvanic protection while retaining the core's mechanical properties.
Question 7: Which structural component transfers control surface loads into the wing main spar?
- Wing fence
- Hinge bracket and torque tube (Correct answer)
- Wing root fairing
- Nacelle strut
Correct answer: Hinge bracket and torque tube
Hinge brackets attach control surfaces to the wing structure, and torque tubes or push-pull rods transfer aerodynamic hinge moments into the primary spar.
Airframe Mechanic Certification Aircraft Structures 3
Which type of wing construction uses the skin as the primary load-carrying element with minimal internal framework?