Airframe Mechanic Certification Aircraft Assembly and Rigging 4 — Questions and Answers
Question 1: On a light aircraft with a conventional landing gear, how is 'toe-in' on the main gear defined?
- The leading edges of the main wheels point slightly inward toward the aircraft centerline when viewed from above (Correct answer)
- The top of the wheels tilt inward toward the fuselage when viewed from the front
- The wheels are canted so the bottoms are farther apart than the tops
- The wheels point outward from the fuselage centerline when viewed from above
Correct answer: The leading edges of the main wheels point slightly inward toward the aircraft centerline when viewed from above
Toe-in means the front of each main wheel points slightly toward the aircraft centerline, reducing side-slip tendency during the ground roll.
Question 2: When assembling a fabric-covered control surface, which material is used to reinforce the attachment area around hinge brackets to prevent tearing?
- Reinforcing tape or patches of the same fabric, applied before the surface covering (Correct answer)
- Fiberglass cloth regardless of the base fabric type
- Sheet aluminum bonded with epoxy over the hinge area
- Additional coats of dope applied only to the hinge zone
Correct answer: Reinforcing tape or patches of the same fabric, applied before the surface covering
Reinforcing tape or additional fabric patches are applied at hinge bracket locations before the finish covering is applied, distributing loads and preventing the covering from tearing.
Question 3: A pulley bracket must be inspected for cracks before installation. Which non-destructive inspection method is most practical for an aluminum pulley bracket in a production environment?
- Dye penetrant inspection (Correct answer)
- Radiographic (X-ray) inspection
- Magnetic particle inspection
- Ultrasonic thickness testing
Correct answer: Dye penetrant inspection
Dye penetrant inspection is practical for aluminum components because aluminum is non-ferromagnetic (ruling out magnetic particle) and the method reveals surface cracks cost-effectively.
Question 4: Which of the following best describes 'geometric twist' in a wing?
- A physical change in the chord line angle from root to tip, independent of airfoil shape change (Correct answer)
- A change in airfoil profile from root to tip while keeping the chord line angle constant
- The difference in sweep angle between the leading and trailing edges
- The variation in dihedral angle along the span
Correct answer: A physical change in the chord line angle from root to tip, independent of airfoil shape change
Geometric (washout/wash-in) twist is a physical rotation of the entire wing section about the span axis, changing the angle of incidence from root to tip.
Question 5: After replacing a control cable on a Cessna 172 elevator system, the technician must verify proper routing. Which publication is the primary reference?
- Cessna 172 Maintenance Manual (Correct answer)
- FAA Advisory Circular AC 43.13-1B
- FAR Part 23 Airworthiness Standards
- FAA Order 8300.10
Correct answer: Cessna 172 Maintenance Manual
The manufacturer's Maintenance Manual contains the approved cable routing diagrams, rigging specifications, and tension values specific to that aircraft model.
Question 6: What is the minimum number of exposed threads that must show beyond a castle (castellated) nut after torquing, before installing a cotter pin?
- At least one full thread must be visible beyond the nut face (Correct answer)
- No thread needs to show; the cotter pin goes through the shank only
- Three full threads must protrude beyond the nut
- The threads must be flush with the nut face
Correct answer: At least one full thread must be visible beyond the nut face
FAA and manufacturer standards require at least one full thread to be visible beyond the castellated nut face to ensure the bolt is properly engaged and the cotter pin slot is accessible.
Question 7: When rigging spoilers on a transport-category aircraft, the technician must verify that spoilers are:
- Flush with the wing upper surface in the retracted position and do not droop below the wing contour (Correct answer)
- Slightly raised in the retracted position to improve boundary layer control
- Set at a fixed deflection angle matching the aileron droop
- Operated independently of all other flight controls in all modes
Correct answer: Flush with the wing upper surface in the retracted position and do not droop below the wing contour
Spoilers must be rigged flush with the wing upper surface when retracted; any droop below the wing contour creates asymmetric drag and can affect roll and lift.
Airframe Mechanic Certification Aircraft Assembly and Rigging 4
On a light aircraft with a conventional landing gear, how is 'toe-in' on the main gear defined?