Airframe Mechanic Certification Aircraft Systems & Components 4 — Questions and Answers
Question 1: What is the function of a torque tube in an aircraft control system?
- Transmit rotational motion to move control surfaces (Correct answer)
- Measure and limit control cable tension
- Connect the rudder pedals to the nose wheel
- Absorb vibration between the engine and airframe
Correct answer: Transmit rotational motion to move control surfaces
A torque tube transmits rotational (torsional) loads to actuate control surfaces such as flaps or ailerons.
Question 2: What is the main advantage of a wet wing fuel tank design compared to a bladder tank?
- Easier to inspect for leaks
- Higher fuel capacity for the same structural weight (Correct answer)
- Simpler to repair when punctured
- Less susceptible to fuel contamination
Correct answer: Higher fuel capacity for the same structural weight
Wet wing tanks use the sealed wing structure itself as the fuel tank, maximizing usable volume without the weight penalty of a separate bladder or tank.
Question 3: An aircraft uses a push-pull tube control system. What is the primary advantage over a cable system?
- Lower cost and easier installation
- Ability to transmit both tension and compression loads (Correct answer)
- Greater flexibility in routing through the airframe
- Less susceptible to temperature-related tension changes
Correct answer: Ability to transmit both tension and compression loads
Push-pull tubes can carry both compressive and tensile loads, providing positive control in both directions without requiring turnbuckles or take-up devices.
Question 4: Which FAA document specifies the minimum inspection requirements for a particular aircraft's airframe?
- Advisory Circular AC 43.13-1B
- The aircraft's FAA-approved Maintenance Manual (Correct answer)
- FAR Part 91
- The Type Certificate Data Sheet (TCDS)
Correct answer: The aircraft's FAA-approved Maintenance Manual
The FAA-approved Maintenance Manual (or Airworthiness Limitations section) for a specific aircraft specifies its mandatory inspection requirements.
Question 5: What type of damage is characterized by a series of parallel scratches or grooves on a mating surface caused by relative motion?
- Spalling
- Fretting (Correct answer)
- Brinelling
- Erosion
Correct answer: Fretting
Fretting damage occurs when two surfaces in contact undergo small oscillatory relative motion, producing parallel scratches and wear debris.
Question 6: When bleeding a hydraulic brake system using the gravity method, fluid is introduced at which point?
- At the wheel cylinder bleeder valve
- At the master cylinder reservoir (Correct answer)
- At the hydraulic system pressure port
- At the selector valve
Correct answer: At the master cylinder reservoir
In gravity bleeding, fluid is added at the master cylinder reservoir and allowed to flow by gravity through the system, pushing air out at the bleeder valves.
Question 7: What is the purpose of a shimmy damper on nose wheel landing gear?
- Prevent over-rotation of the nose wheel during turns
- Dampen rapid oscillations of the nose wheel about its vertical axis (Correct answer)
- Limit nose gear extension speed during gear lowering
- Center the nose wheel for retraction
Correct answer: Dampen rapid oscillations of the nose wheel about its vertical axis
A shimmy damper is a hydraulic or friction device that dampens rapid side-to-side oscillations (shimmy) of the nose wheel.
Airframe Mechanic Certification Aircraft Systems & Components 4
What is the function of a torque tube in an aircraft control system?