Free AMT Aircraft Structures and Materials Questions and Answers 1 — Questions and Answers
Question 1: In a semi-monocoque fuselage, what is the primary function of the longerons and stringers?
- To provide the aerodynamic shape and contour of the fuselage.
- To act as the primary tension and compression-resisting members in the longitudinal direction. (Correct answer)
- To transfer concentrated loads from the wings and empennage directly to the skin.
- To serve as attachment points for cabin interior components and systems only.
Correct answer: To act as the primary tension and compression-resisting members in the longitudinal direction.
In semi-monocoque construction, the skin carries a significant portion of the torsional and shear loads, but the longerons and stringers are the primary members that resist axial (tension and compression) loads due to bending of the fuselage.
Question 2: A technician discovers fine, worm-like tracks under the paint on an aluminum skin panel, particularly in an area of high humidity. What type of corrosion is most likely present?
- Pitting corrosion
- Intergranular corrosion
- Filiform corrosion (Correct answer)
- Galvanic corrosion
Correct answer: Filiform corrosion
Filiform corrosion is characterized by its distinctive worm-like appearance and occurs on metal surfaces with an organic coating system, especially in high-humidity environments.
Question 3: Which of the following materials is commonly used for its high strength-to-weight ratio, excellent corrosion resistance, and ability to withstand high temperatures, making it ideal for engine components and critical airframe structures?
- Magnesium alloy
- Titanium alloy (Correct answer)
- 4130 Chromoly steel
- 2024 Aluminum alloy
Correct answer: Titanium alloy
Titanium alloys are widely used in aerospace for their superior strength-to-weight ratio, resistance to corrosion, and ability to maintain strength at elevated temperatures, which are critical properties for jet engine parts and highly stressed airframe sections.
Question 4: When inspecting a composite honeycomb sandwich structure, what is the primary purpose of the honeycomb core?
- To provide a high degree of thermal insulation.
- To carry the majority of the tensile and compressive loads.
- To stabilize the face sheets and carry shear loads. (Correct answer)
- To increase the overall density and mass of the component.
Correct answer: To stabilize the face sheets and carry shear loads.
The honeycomb core in a sandwich panel functions to separate the two high-strength face sheets and transfer shear loads between them. This separation dramatically increases the panel's stiffness and resistance to bending, while the core itself stabilizes the face sheets against buckling.
Question 5: A maintenance technician needs to inspect a composite wing panel for suspected subsurface delamination after a minor impact event that left no visible surface damage. Which of the following NDT methods is most suitable for this task?
- Dye penetrant inspection
- Magnetic particle inspection
- Eddy current inspection
- Ultrasonic inspection (Correct answer)
Correct answer: Ultrasonic inspection
Ultrasonic testing (UT) is the most widely used and effective non-destructive method for detecting subsurface defects like delaminations, voids, and impact damage in composite structures, as sound waves can travel through the material and detect internal anomalies.
Question 6: The design principle that ensures a structure can withstand specific loads without permanent deformation is known as its:
- Ultimate strength
- Fatigue life
- Elastic limit (Correct answer)
- Creep resistance
Correct answer: Elastic limit
The elastic limit is the maximum stress a material can withstand before it begins to deform permanently (plastically). Aircraft structures are designed to operate within this limit during normal flight loads to ensure they return to their original shape.
Free AMT Aircraft Structures and Materials Questions and Answers 1
In a semi-monocoque fuselage, what is the primary function of the longerons and stringers?