Airframe Mechanic Certification Aircraft Systems & Components 3 — Questions and Answers
Question 1: What is the primary structural function of an aircraft's longerons?
- Resist torsional loads on the fuselage
- Carry primary bending loads along the length of the fuselage (Correct answer)
- Provide attachment points for wing spars
- Transmit engine thrust to the airframe
Correct answer: Carry primary bending loads along the length of the fuselage
Longerons are primary longitudinal structural members that carry bending loads along the fuselage length.
Question 2: In an oleo-pneumatic landing gear strut, which two fluids are typically used?
- Water and hydraulic fluid
- Hydraulic fluid and nitrogen (Correct answer)
- Air and brake fluid
- Hydraulic fluid and oxygen
Correct answer: Hydraulic fluid and nitrogen
Oleo struts use hydraulic fluid to dampen shock loads and nitrogen (or air) as a compressible medium to absorb landing energy.
Question 3: What does the term 'dihedral' refer to in aircraft wing design?
- The sweep angle of the wing leading edge
- The upward angle of the wings relative to the horizontal (Correct answer)
- The taper ratio from root to tip
- The thickness-to-chord ratio of the airfoil
Correct answer: The upward angle of the wings relative to the horizontal
Dihedral is the upward angle of the wings from the root to the tip when viewed from the front, which improves lateral stability.
Question 4: Which type of rivet is NOT suitable for use in aircraft structural applications?
- MS20470 (universal head)
- MS20426 (countersunk head)
- MS20615 (brazier head)
- Pop (blind) rivet in primary structure (Correct answer)
Correct answer: Pop (blind) rivet in primary structure
Pop (blind) rivets are not approved for use in primary structural applications because they do not provide the same strength as solid shank rivets.
Question 5: What is the purpose of a fire sleeve on aircraft tubing?
- Prevent electrolytic corrosion between dissimilar metals
- Provide fire-resistant protection for fluid-carrying lines (Correct answer)
- Reduce aerodynamic drag on exposed tubing
- Insulate tubing from temperature extremes during ground operations
Correct answer: Provide fire-resistant protection for fluid-carrying lines
Fire sleeves are installed over fluid-carrying lines in engine compartments to protect them from flame and heat in the event of a fire.
Question 6: When inspecting a control surface for freedom of movement, a technician notes binding. What is the FIRST corrective step?
- Adjust cable tension to compensate
- Identify and remove the source of binding before flight (Correct answer)
- Lubricate the hinges and recheck
- Log the discrepancy and release for flight
Correct answer: Identify and remove the source of binding before flight
Binding in a control surface is a flight safety issue; the source must be identified and corrected before the aircraft is released for flight.
Question 7: Which material is most commonly used for aircraft firewall construction?
- Carbon fiber composite
- Stainless steel or titanium (Correct answer)
- 2024-T3 aluminum alloy
- Fiberglass laminate
Correct answer: Stainless steel or titanium
Firewalls are constructed of stainless steel or titanium because these materials resist high temperatures and open flame better than aluminum or composites.
Airframe Mechanic Certification Aircraft Systems & Components 3
What is the primary structural function of an aircraft's longerons?