Airframe Mechanic Certification Aircraft Assembly and Rigging 2 — Questions and Answers
Question 1: When rigging a conventional (non-fly-by-wire) aileron control system, what is the correct method to check for cable tension?
- Use a tensiometer and compare readings to the manufacturer's temperature-tension chart (Correct answer)
- Pull each cable with your hand and estimate tension by feel
- Measure cable deflection under a 10-pound load at the midspan
- Check tension only when the aircraft is at operating temperature
Correct answer: Use a tensiometer and compare readings to the manufacturer's temperature-tension chart
A tensiometer is used to measure cable tension, and readings must be corrected using the manufacturer's temperature-tension chart because tension varies with ambient temperature.
Question 2: Which type of turnbuckle safetying method is approved for primary flight control cables?
- Clip-locking method only
- Wire-wrapping (pigtail) method or clip-locking method, per manufacturer approval (Correct answer)
- Safety wire through the barrel only
- Locking nut on each end of the barrel
Correct answer: Wire-wrapping (pigtail) method or clip-locking method, per manufacturer approval
Both the double-wrap wire method and clip-locking turnbuckle assemblies are FAA-approved; the applicable method depends on the turnbuckle design and manufacturer data.
Question 3: During horizontal tail assembly, the stabilizer incidence angle is found to be 0.5° more than specified. What is the most appropriate corrective action?
- Adjust the stabilizer attach bolts to shim the leading edge up or down as needed (Correct answer)
- Replace the horizontal stabilizer
- Adjust the elevator trim tab to compensate
- File a maintenance record and leave the incidence as found
Correct answer: Adjust the stabilizer attach bolts to shim the leading edge up or down as needed
Small incidence errors are corrected by adding or removing shims at the stabilizer attachment points to achieve the manufacturer's specified angle.
Question 4: What does 'wash-in' mean when applied to a fixed-wing aircraft?
- Increasing the angle of incidence from root to tip on one wing (Correct answer)
- Decreasing the angle of incidence from root to tip
- Twisting the wing so the tip has a lower angle of attack than the root
- Adding dihedral to an existing wing
Correct answer: Increasing the angle of incidence from root to tip on one wing
Wash-in is a wing twist that increases the angle of incidence toward the wingtip, causing the tip to stall before the root and affecting roll characteristics.
Question 5: A bellcrank in a flight control system is used primarily to:
- Change the direction of control cable or rod movement (Correct answer)
- Increase cable tension automatically
- Serve as a cable anchor point at the wing root
- Reduce friction in push-pull tube systems
Correct answer: Change the direction of control cable or rod movement
A bellcrank converts or redirects the motion of cables or rods, allowing control forces to be transmitted around corners or change direction within the airframe.
Question 6: When installing a push-pull control tube, what inspection is required before installation?
- Inspect for straightness, cracks, corrosion, and verify end fitting torque values (Correct answer)
- Only check that the tube length matches the drawing dimension
- Pressure-test the tube to 150% of design load
- Verify the tube ID matches the cable diameter
Correct answer: Inspect for straightness, cracks, corrosion, and verify end fitting torque values
Push-pull tubes must be inspected for straightness (within limits), freedom from cracks and corrosion, and end fittings must be properly torqued and safetied.
Question 7: Which document defines the maximum allowable play (free movement) in a flight control system for a certificated aircraft?
- The aircraft's Type Certificate Data Sheet (TCDS) or Aircraft Maintenance Manual (Correct answer)
- FAR Part 23 only, regardless of aircraft type
- The rigging crew's standard operating procedure
- AC 43.13-1B alone
Correct answer: The aircraft's Type Certificate Data Sheet (TCDS) or Aircraft Maintenance Manual
Allowable control system free play is specified in the manufacturer's Aircraft Maintenance Manual or referenced in the TCDS, which takes precedence over generic advisory materials.
