Airframe Mechanic Certification Assembly and Rigging 4 — Questions and Answers
Question 1: Which of the following cable materials is NOT recommended for primary flight control systems due to its susceptibility to corrosion?
- Stainless steel cable (MIL-W-83420)
- Carbon steel cable without coating
- Galvanized carbon steel cable
- Both B and C (Correct answer)
Correct answer: Both B and C
Both uncoated and galvanized carbon steel cables corrode more readily than stainless steel and are not recommended for primary flight controls in corrosive environments.
Question 2: What is the purpose of a 'sector' (or quadrant) in a flight control system?
- It amplifies control input force
- It converts linear cable motion to rotational motion at the control surface (Correct answer)
- It limits maximum surface deflection
- It provides a pulley for cable direction changes
Correct answer: It converts linear cable motion to rotational motion at the control surface
A sector (quadrant) is a curved drum or arc that converts the linear pull of a cable into rotational movement to deflect a control surface.
Question 3: After replacing a flight control cable, which of the following is the LAST step before returning the aircraft to service?
- Installing and safety-wiring all turnbuckles
- Setting cable tension with a tensiometer
- Performing a complete functional check of the control system through full travel (Correct answer)
- Inspecting all cable guides and pulleys for wear
Correct answer: Performing a complete functional check of the control system through full travel
A complete functional check through full travel is the final verification that the entire system operates correctly and without binding before return to service.
Question 4: A control cable shows a broken wire strand on the outside of a bend near a pulley. Per AC 43.13-1B, this cable should be:
- Repaired using a splice fitting
- Monitored at each 100-hour inspection
- Replaced immediately (Correct answer)
- Reported to the FAA before further flight
Correct answer: Replaced immediately
AC 43.13-1B requires replacement of any cable with a broken wire at a bend, as this indicates fatigue and the cable's integrity is compromised.
Question 5: Wing dihedral angle is measured as the angle between the:
- Wing chord line and the longitudinal axis of the fuselage
- Wing leading edge and the horizontal
- Spanwise axis of the wing and the horizontal plane (Correct answer)
- Wing upper surface and the vertical
Correct answer: Spanwise axis of the wing and the horizontal plane
Dihedral angle is the upward angle of the wing's spanwise axis (or a reference line along the wing) relative to the horizontal plane.
Question 6: During assembly of a fabric-covered biplane, the wings must be aligned so that there is no 'stagger error.' Stagger refers to:
- The vertical offset between upper and lower wing attachment points
- The fore-and-aft offset of the upper wing relative to the lower wing (Correct answer)
- The difference in incidence angle between upper and lower wings
- The lateral offset of the wing panels relative to the fuselage centerline
Correct answer: The fore-and-aft offset of the upper wing relative to the lower wing
Stagger is the fore-and-aft (longitudinal) displacement of the upper wing's leading edge relative to the lower wing's leading edge.
Question 7: When installing a clevis pin in a flight control linkage, what secures the clevis pin to prevent it from backing out?
- A cotter pin through the drilled hole in the shank (Correct answer)
- Safety wire wrapped around the head
- A castellated nut and cotter pin
- A snap ring in the groove at the pin tip
Correct answer: A cotter pin through the drilled hole in the shank
Clevis pins used in control linkages are typically secured by a cotter pin inserted through a hole drilled through the end of the pin's shank.
Airframe Mechanic Certification Assembly and Rigging 4
Which of the following cable materials is NOT recommended for primary flight control systems due to its susceptibility to corrosion?