Airframe Mechanic Certification Flight Control Systems 3 — Questions and Answers
Question 1: What is the maximum allowable turnbuckle barrel thread exposure on a properly rigged flight control cable?
- 1 thread
- 2 threads
- 3 threads (Correct answer)
- 4 threads
Correct answer: 3 threads
FAA guidelines specify no more than three threads of a turnbuckle barrel may be exposed on either side after rigging is complete.
Question 2: Frise ailerons are designed primarily to:
- Increase roll rate at low speeds
- Reduce adverse yaw by creating drag on the rising wing (Correct answer)
- Allow differential aileron travel
- Prevent aileron flutter at high speeds
Correct answer: Reduce adverse yaw by creating drag on the rising wing
The Frise aileron's leading edge protrudes below the wing surface when raised, creating parasite drag that counters adverse yaw.
Question 3: Which document specifies the required flight control surface travel limits for a certificated aircraft?
- AC 43.13-1B
- The applicable Aircraft Maintenance Manual (AMM) (Correct answer)
- CFR Part 23 alone
- The pilot's operating handbook (POH) only
Correct answer: The applicable Aircraft Maintenance Manual (AMM)
The Aircraft Maintenance Manual contains model-specific rigging data, including required control surface travel limits and tolerances.
Question 4: A spoiler used as a roll control device operates by:
- Deflecting downward on the high wing to increase lift
- Deflecting upward on the high wing to reduce lift and increase drag (Correct answer)
- Acting in concert with ailerons to increase pitch authority
- Extending symmetrically on both wings during roll
Correct answer: Deflecting upward on the high wing to reduce lift and increase drag
Roll spoilers deploy on the high (upgoing) wing, destroying lift and increasing drag to assist or replace aileron roll control.
Question 5: What type of rig check uses a protractor or inclinometer placed on the control surface to measure deflection angles?
- Tension check
- Continuity check
- Travel check (Correct answer)
- Friction check
Correct answer: Travel check
A travel check uses a protractor or rigging board placed on the control surface to measure deflection in degrees against AMM specifications.
Question 6: What is the function of an antiservo tab on a stabilator?
- It assists the pilot by reducing the force required to move the stabilator
- It opposes stabilator movement to provide control feel and prevent overcontrol (Correct answer)
- It trims out stabilator forces during climb only
- It prevents the stabilator from exceeding its structural limits
Correct answer: It opposes stabilator movement to provide control feel and prevent overcontrol
An antiservo (antibalance) tab deflects in the same direction as the stabilator, creating aerodynamic resistance that gives the pilot proper control feel.
Question 7: During a walk-around inspection, a pilot notices excessive freeplay in the aileron. As an A&P mechanic, your first action should be to:
- Adjust cable tension to the maximum allowable
- Inspect the control system per the AMM to identify the source of freeplay (Correct answer)
- Clear the aircraft for flight if freeplay is within 1 inch
- Report it only if the aircraft is IFR
Correct answer: Inspect the control system per the AMM to identify the source of freeplay
Excessive freeplay must be traced to its source — worn bearings, loose linkages, or cable slack — and corrected per the AMM before further flight.
Airframe Mechanic Certification Flight Control Systems 3
What is the maximum allowable turnbuckle barrel thread exposure on a properly rigged flight control cable?