Airframe Mechanic Certification Assembly and Rigging 5 — Questions and Answers
Question 1: What effect does temperature have on control cable tension in an aircraft?
- Temperature has no measurable effect on cable tension
- Higher temperatures increase cable tension due to thermal expansion of the cable
- Higher temperatures decrease cable tension as the cable expands and the structure expands more (Correct answer)
- Cable tension must only be checked at standard sea-level temperature
Correct answer: Higher temperatures decrease cable tension as the cable expands and the structure expands more
As temperature rises, both the cable and the airframe expand, but typically the aluminum airframe expands more than the steel cable, reducing cable tension.
Question 2: A helicopter tail rotor pitch change link is found to be bent. The correct action is to:
- Carefully straighten the link in a press if the bend is less than 10°
- Replace the link with a serviceable part (Correct answer)
- Inspect the link for cracks and return to service if none are found
- Safety-wire the link in the bent position and document in the logbook
Correct answer: Replace the link with a serviceable part
Flight control components that are bent must be replaced; straightening is not an approved repair for flight-critical linkages.
Question 3: When assembling a modular aircraft fuselage, what is typically used to ensure proper alignment of major structural assemblies before final fastener installation?
- Alignment fixtures or assembly jigs specified by the manufacturer (Correct answer)
- Adjustable clamps and mechanic's judgment
- Laser levels and plumb bobs from adjacent structure
- Center-of-gravity measurement equipment
Correct answer: Alignment fixtures or assembly jigs specified by the manufacturer
Manufacturer-specified assembly jigs and fixtures ensure that major structural components are held in the correct position and alignment during assembly.
Question 4: The term 'incidence' as applied to a fixed-wing aircraft refers to:
- The angle between the wing chord line and the horizontal datum of the aircraft (Correct answer)
- The angle of attack at cruise speed
- The angle between the wing leading edge and the fuselage centerline
- The upward angle of the wing from root to tip
Correct answer: The angle between the wing chord line and the horizontal datum of the aircraft
Wing incidence (rigging incidence) is the angle between the wing chord line and the aircraft's longitudinal axis (horizontal datum).
Question 5: Excessive friction (stiffness) in a flight control system is MOST dangerous because it:
- Reduces maximum control surface deflection
- Masks control feedback and can prevent the pilot from detecting aerodynamic loads (Correct answer)
- Increases cable tension beyond limits
- Causes premature wear of pulleys and fairleads
Correct answer: Masks control feedback and can prevent the pilot from detecting aerodynamic loads
High friction masks aerodynamic loads (stick forces) and may prevent the pilot from feeling control surface buffet or overload, reducing situational awareness.
Question 6: What is the maximum number of turnbuckle threads that should be exposed outside a turnbuckle barrel after final rigging?
- No more than two threads
- No more than three threads (Correct answer)
- No more than four threads
- No more than six threads
Correct answer: No more than three threads
No more than three threads of a turnbuckle terminal should be exposed (visible outside the barrel) after rigging to ensure adequate thread engagement.
Question 7: During a rigging check, the rudder is found to be displaced 3° left of center when the rudder pedals are centered. The FIRST corrective action should be to:
- Shorten the right rudder cable by adjusting the turnbuckle
- Check and equalize the tension in both rudder cables (Correct answer)
- Adjust the rudder stop to match the displaced position
- Remove and reinstall the rudder hinges
Correct answer: Check and equalize the tension in both rudder cables
Unequal rudder cable tension is the most common cause of a displaced control surface with centered pedals, and equalizing tension is the first step.
Airframe Mechanic Certification Assembly and Rigging 5
What effect does temperature have on control cable tension in an aircraft?