Airframe Structures & Systems Flashcards

What is the primary function of an aircraft's wing spar?

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.

Which material is commonly used in modern aircraft primary structures due to its high strength-to-weight ratio?

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.

What is the purpose of a doubler in aircraft structural repair?

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.

Which type of corrosion appears as thread-like lines under paint on aluminum surfaces?

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.

What is the correct sequence for installing a rivet in structural repair?

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.

Which structural component primarily absorbs landing impact forces?

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.

What is the purpose of a wing's leading-edge slat?

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.

Which inspection method is best for detecting internal cracks in aluminum structures?

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.

What is the primary role of a fuselage frame in aircraft structure?

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.