Free A&P Airframe Structures & Systems Questions and Answers — Questions and Answers
Question 1: What is the primary function of an aircraft's wing spar?
- To provide electrical power to the wing.
- To carry the majority of the bending & torsional loads. (Correct answer)
- To control the aircraft's fuel flow.
- To house the landing gear mechanism.
Correct answer: To carry the majority of the bending & torsional loads.
The wing spar is a principal structural member running spanwise through the wing, acting as its backbone. Its primary function is to withstand and transmit the significant bending forces (due to lift and weight) and torsional loads (twisting forces) experienced by the wing during flight, ensuring the aircraft's structural integrity.
Question 2: Which material is commonly used in modern aircraft primary structures due to its high strength-to-weight ratio?
- Cast iron
- Aluminum alloys
- Carbon fiber reinforced polymer (CFRP) (Correct answer)
- Wood
Correct answer: Carbon fiber reinforced polymer (CFRP)
Carbon fiber reinforced polymer (CFRP) is widely used in modern aircraft primary structures due to its exceptional strength-to-weight ratio and stiffness. Its lightweight yet robust properties contribute significantly to improved fuel efficiency and enhanced performance compared to traditional metallic materials like aluminum.
Question 3: What is the purpose of a doubler in aircraft structural repair?
- To increase electrical conductivity.
- To provide a decorative finish.
- To add extra strength & distribute loads. (Correct answer)
- To reduce aerodynamic drag.
Correct answer: To add extra strength & distribute loads.
In aircraft structural repair, a doubler is a piece of material, typically metal, that is riveted or bonded over a damaged or weakened area. Its purpose is to reinforce the structure, restore its original strength, and effectively distribute stress loads away from the compromised section, preventing further failure.
Question 4: Which type of corrosion appears as thread-like lines under paint on aluminum surfaces?
- Galvanic corrosion
- Pitting corrosion
- Filiform corrosion (Correct answer)
- Stress corrosion cracking
Correct answer: Filiform corrosion
Filiform corrosion is a distinctive type of corrosion that appears as thread-like filaments growing under a protective coating, typically paint, on aluminum or magnesium surfaces. It initiates at small defects in the coating and propagates as a result of differential aeration cells, often resembling fine worms.
Question 5: What is the correct sequence for installing a rivet in structural repair?
- Drill hole → Insert rivet → Buck tail → Inspect (Correct answer)
- Buck tail → Drill hole → Insert rivet → Inspect
- Insert rivet → Buck tail → Drill hole → Inspect
- Inspect → Buck tail → Drill hole → Insert rivet
Correct answer: Drill hole → Insert rivet → Buck tail → Inspect
The correct sequence for installing a rivet ensures a strong and proper connection in structural repair. First, a precise hole is drilled, then the rivet is inserted into the hole. Next, the "buck tail" is formed by deforming the rivet's shank, creating a secure joint, and finally, the installation is inspected for quality and integrity.
Question 6: Which structural component primarily absorbs landing impact forces?
- Vertical stabilizer
- Landing gear struts & shock absorbers (Correct answer)
- Wing flaps
- Engine mounts
Correct answer: Landing gear struts & shock absorbers
The landing gear struts and their integrated shock absorbers are specifically designed to absorb and dissipate the significant impact forces generated during an aircraft's landing. They convert the kinetic energy of the impact into heat, preventing damage to the airframe and ensuring a smooth touchdown for passengers and cargo.
Question 7: What is the purpose of a wing's leading-edge slat?
- To reduce engine noise.
- To enhance high-speed stability.
- To delay airflow separation & increase lift during takeoff/landing. (Correct answer)
- To store fuel reserves.
Correct answer: To delay airflow separation & increase lift during takeoff/landing.
Leading-edge slats are movable aerodynamic surfaces on the front of the wing that extend during takeoff and landing. Their purpose is to create a slot that re-energizes the airflow over the wing, delaying flow separation at high angles of attack, thereby increasing lift and reducing stall speed for safer operations.
Question 8: Which inspection method is best for detecting internal cracks in aluminum structures?
- Visual inspection
- Eddy current testing (Correct answer)
- Tapping with a hammer
- Magnetic particle inspection (for ferrous metals only)
Correct answer: Eddy current testing
Eddy current testing is a non-destructive inspection method particularly effective for detecting surface and subsurface cracks, corrosion, and other discontinuities in conductive materials like aluminum. It works by inducing eddy currents in the material and detecting changes in these currents caused by flaws, without damaging the component.
Question 9: What is the primary role of a fuselage frame in aircraft structure?
- To generate thrust.
- To provide the main lifting surface.
- To support the skin & distribute loads. (Correct answer)
- To control yaw movement.
Correct answer: To support the skin & distribute loads.
Fuselage frames, such as bulkheads and formers, are essential structural components that provide the basic shape and rigidity to the aircraft's body. Their primary role is to support the external skin, which often carries significant loads, and to distribute various aerodynamic and operational stresses throughout the airframe. This ensures the structural integrity of the aircraft and prevents deformation under flight conditions.
Free A&P Airframe Structures & Systems Questions and Answers
What is the primary function of an aircraft's wing spar?