18 Flight Controls & Rigging Practice Questions & Answers
Every Flight Controls & Rigging practice question from the FAA A&P Airframe (AMA) Practice Test, with the correct answer and a short explanation.
Start practice test →1. After a turnbuckle in a flight control cable system has been adjusted to the correct cable tension, how many threads may remain exposed outside the barrel?
- A.Not more than three threads on either side of the barrel✓ Answer
- B.No threads at all on either side of the barrel
- C.Not more than seven threads on either side of the barrel
- D.Not more than four threads on either side of the barrel
Advisory Circular 43.13-1 limits exposed thread to three threads on either side of the barrel after adjustment, because more exposure means too little thread is engaged in the barrel to develop the joint's full strength. The widely repeated "four threads" figure is a different rule: on initial installation the terminals should not be screwed into the barrel more than four threads.
Source: AC 43.13-1, Ch. 7 (Turnbuckles and cable adjustment)Report a problem with this question
2. When safety wire is used to secure a turnbuckle in a flight control cable system, which practice is correct?
- A.Soft copper wire is preferred because it can be broken by hand at inspection
- B.The double-wrap method is preferred, with at least four turns of wire around each shank✓ Answer
- C.Safety wire removed from a turnbuckle may be reused if it is not kinked or corroded
- D.The single-wrap method is preferred, with at least two turns of wire around each shank
Advisory Circular 43.13-1 names the double-wrap method as the preferred way to safety a turnbuckle and requires the wire to be wrapped at least four turns around the shank at each end, which locks the barrel against rotation. Safety wire is never reused because bending work-hardens it, and soft copper wire that breaks by hand is used only on emergency-equipment seals, not on flight controls.
Source: AC 43.13-1, Ch. 7 (Turnbuckle safetying)Report a problem with this question
3. During an inspection, a mechanic finds one broken wire strand in a control cable at the point where the cable passes over a pulley. What action does this condition require?
- A.The cable assembly must be replaced before further flight✓ Answer
- B.The cable may remain in service if tension is still within limits
- C.The broken wire may be trimmed off and the cable relubricated
- D.The cable may remain in service until three wires are broken
A pulley run is a critical fatigue area, and Advisory Circular 43.13-1 requires replacement of the cable assembly when even one broken wire strand is found in such an area. Critical fatigue areas also include any part of the working length that is flexed, rubbed or worked, and any point within one foot of a swaged fitting, because a single break there signals that the remaining wires are already fatigued.
Source: AC 43.13-1, Ch. 7 (Control cable inspection)Report a problem with this question
4. A mechanic passes a cloth along the length of a control cable and the cloth snags. What does this indicate?
- A.Broken wire strands in the cable✓ Answer
- B.Excessive wear of the outer wires
- C.Loss of internal lubricant in the cable
- D.Internal corrosion beneath the outer wires
The cloth snags because a broken wire end protrudes from the lay of the strand and catches the weave, so the test detects broken wires and nothing else. Internal corrosion is found by relieving tension and twisting the cable open, and wear is judged by whether the outer wires have flattened to 40 to 50 percent of their diameter, so a broken wire may also lie in the helix and require a magnifying glass to see.
Source: AC 43.13-1, Ch. 7 (Control cable inspection)Report a problem with this question
5. What is the acceptable method of removing light surface rust and dirt from a steel control cable?
- A.Rub the cable with fine metallic wool until the surface is bright
- B.Wash the cable with an approved petroleum solvent, then wipe it dry
- C.Wipe the cable with a clean, dry, coarse-weave cloth or a fiber brush✓ Answer
- D.Polish the cable with fine abrasive paper, then apply light oil
A dry coarse-weave rag or fiber brush lifts loose rust without adding anything harmful to the cable. Metallic wool is prohibited because it embeds dissimilar metal particles that set up galvanic corrosion, and solvents are prohibited because they wash the internal lubricant out from between the strands, and abrasives remove the protective coating from the wires.
Source: AC 43.13-1, Ch. 7 (Control cable maintenance and cleaning)Report a problem with this question
6. Before a cable rigging chart can be used to determine the correct tension for a flight control cable, what two items must be known?
- A.The cable construction and the number of pulleys in the run
- B.The cable diameter and the ambient air temperature✓ Answer
- C.The cable diameter and the total length of the cable run
- D.The cable breaking strength and the ambient air temperature
A rigging chart is entered with cable size on one scale and ambient air temperature on the other, and the intersection gives the rigging load in pounds. Temperature is required because the aluminum structure expands more than the steel cable as it warms, so the correct rigging load rises with temperature, and on long runs an average of two or three temperature readings is used.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Cable tension)Report a problem with this question
7. How does a cable tensiometer determine the tension in an installed control cable?
- A.A riser offsets the cable between two anvils and the force required is read on the dial✓ Answer
- B.A calibrated spring stretches the cable between two anvils and the stretch is read on the dial
- C.A known weight hung on the cable deflects it and the deflection is read on a scale
- D.A strain gauge clamped to the cable measures elongation of the outer wire strands
The cable is laid across two hardened anvils and a riser, or plunger, pushes it out of line; the force needed to create that offset is proportional to cable tension and drives the dial pointer. Because the offset force also depends on cable diameter, a numbered riser is selected for the cable size and a conversion chart translates the dial reading into pounds, and the instrument must be on a calibration schedule to stay accurate.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Cable tension)Report a problem with this question
8. Why are automatic cable tension regulators installed in the flight control systems of large airplanes?
- A.Because pulley bearings wear in service and gradually introduce slack into the cable runs
- B.Because cable tension must be increased automatically as airspeed and air loads increase
- C.Because steel cables stretch permanently in service and the slack must be taken up automatically
- D.Because the aluminum structure expands and contracts more with temperature than the steel cables✓ Answer
Aluminum has a higher coefficient of thermal expansion than steel, so on a long fuselage the structure grows or shrinks more than the cable and tension would otherwise change with temperature and altitude. The regulator uses a compression spring to take up or pay out cable and hold tension constant, and its locking mechanism allows correction only when the system is in neutral so it cannot interfere with a control input.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Cable tension regulators)Report a problem with this question
9. What is the maximum angle through which a control cable may be deflected by a fairlead?
- A.15 degrees
- B.5 degrees
- C.10 degrees
- D.3 degrees✓ Answer
Advisory Circular 43.13-1 limits fairlead deflection to three degrees because a fairlead is a rubbing guide, not a bearing, and a larger angle loads the phenolic block and abrades the cable. Anything that must turn the cable through a greater angle has to be a pulley, which lets the cable roll rather than slide.
Source: AC 43.13-1, Ch. 7 (Fairleads and cable guides)Report a problem with this question
10. After a swage-type terminal has been installed and the shank checked with a go/no-go gauge, the finished cable assembly is proof-loaded to what portion of the cable's rated breaking strength?
- A.60 percent✓ Answer
- B.100 percent
- C.80 percent
- D.40 percent
Advisory Circular 43.13-1 calls for a proof load of 60 percent of the cable's rated breaking strength, applied gradually and held about three minutes with a guard in place, which proves the swage without yielding the cable. The junction of cable and fitting is then marked with paint so any later slippage shows up as a gap in the painted band.
Source: AC 43.13-1, Ch. 7 (Swaged cable terminals and proof testing)Report a problem with this question
11. How is adequate thread engagement of a rod end in a push-pull control rod verified?
- A.The rod end is measured; if two threads show past the checknut, engagement is adequate
- B.A wire is placed in the inspection hole; if it passes through freely, engagement is adequate
- C.A wire is placed in the inspection hole; if it cannot pass through, engagement is adequate✓ Answer
- D.The checknut is tightened; if it seats fully against the rod, engagement is adequate
The inspection hole, also called a witness hole, is drilled through the rod at the minimum thread engagement point, so if the rod end is screwed in far enough its shank blocks the hole and a wire cannot be pushed through. A wire that passes freely proves the rod end is backed out too far and the joint could pull out under load, no matter how tight the checknut feels.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Push-pull tubes and control rods)Report a problem with this question
12. Which tab moves in the SAME direction as the control surface to which it is attached?
- A.Anti-servo tab✓ Answer
- B.Balance tab
- C.Servo tab
- D.Spring tab
The anti-servo, or anti-balance, tab is linked so that it deflects the same way the surface does, which increases the aerodynamic force the pilot must overcome and de-sensitizes a control that would otherwise be too responsive, which is why it is typical on a stabilator. Balance, servo, spring and trim tabs all move opposite the surface, either to reduce the control force or to hold the airplane in trim.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 1 (Flight control tabs)Report a problem with this question
13. What is the function of a servo tab?
- A.It moves with the primary surface and increases the force required at the flight deck control
- B.It is moved by the flight deck control and aerodynamically positions the primary surface✓ Answer
- C.It is bent on the ground by the mechanic and its setting is verified by a test flight
- D.It is set by the pilot through independent linkage to hold the airplane in hands-off flight
On a servo tab system the flight deck control is connected to the tab rather than to the surface, so deflecting the tab generates an aerodynamic moment that drives the primary surface to its new position with very little pilot effort. That is why servo tabs are used on large airplanes as a primary or backup means of control, for example after a loss of hydraulic boost.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 1 (Flight control tabs)Report a problem with this question
14. A control surface removed for a static balance check is supported at its hinge points and the trailing edge settles below the horizontal. How is this condition described and recorded?
- A.Overbalance, recorded with a plus sign
- B.Overbalance, recorded with a minus sign
- C.Underbalance, recorded with a minus sign
- D.Underbalance, recorded with a plus sign✓ Answer
A trailing edge that drops below horizontal means the center of gravity lies aft of the hinge center line, which is tail-heavy static underbalance and is recorded as a plus value. Manufacturers generally prohibit tail-heavy underbalance and prefer a nose-heavy, or overbalance, condition recorded as minus, because mass behind the hinge line is what feeds flutter.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Rebalancing of control surfaces)Report a problem with this question
15. Why must the control surfaces be rebalanced after an airplane has been repainted?
- A.Paint solvents attack the balance weight attachment and can allow the weight to work loose
- B.Added paint aft of the hinge line moves the surface center of gravity rearward and invites flutter✓ Answer
- C.Added paint changes the surface contour and reduces the effectiveness of the trim tab
- D.Added paint at the hinges increases friction in the bearings and can cause the controls to bind
Most of a control surface's area lies behind the hinge line, so even a few extra coats of paint add far more moment aft of the hinge than forward of it and shift the center of gravity rearward. That rearward shift is the classic cause of flutter, which is also why any repair that adds or removes weight either side of the hinge center line, and trapped water or ice inside the surface, require the same attention.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Rebalancing of control surfaces)Report a problem with this question
16. In a correctly rigged flight control system, which stops normally limit the travel of the control surface?
- A.Neither set; travel is limited by cable tension and the turnbuckle adjustment
- B.Both sets contact at the same instant so that they share the load equally
- C.The stops at the flight deck control, with the surface stops set as override stops
- D.The stops at the control surface, with the flight deck stops set as override stops✓ Answer
Rigging is done so the surface stops take the aerodynamic load, while the flight deck stops are adjusted to a definite clearance beyond that point so they only act if the cables stretch during a violent maneuver. The proof of correct rigging is spring-back: the surface reaches its stop first, and a small additional push is needed before the flight deck control meets its own stop, and travel must always be checked by operating the controls from the flight deck rather than by moving the surfaces by hand.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 2 (Airplane assembly and rigging)Report a problem with this question
17. What distinguishes a Fowler flap from a plain or split flap?
- A.It hinges down from the lower surface only, increasing camber and drag
- B.It moves aft as it lowers, increasing both wing area and camber✓ Answer
- C.It moves forward and down from the leading edge to delay separation
- D.It opens a gap that ducts air over the upper surface of the flap
A Fowler flap rides aft on tracks as it deflects, so it enlarges the wing's effective area in addition to adding camber, which is why it produces the greatest lift increase of the common trailing-edge flaps. The other choices describe a split flap, a slotted flap and a leading-edge slat, none of which change wing area.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 1 (Wing flaps and high-lift devices)Report a problem with this question
18. What do flight spoilers on a transport airplane do?
- A.They increase wing camber on landing, working with the flaps to shorten the roll
- B.They increase lift and reduce drag, allowing a steeper approach at low speed
- C.They deflect air over the ailerons to restore roll control at high angles of attack
- D.They reduce lift and increase drag, assisting roll and acting as speed brakes✓ Answer
Spoilers are upper-surface panels that spoil the airflow when raised, destroying lift and adding drag; raised asymmetrically with the up-going aileron they help roll the airplane, and raised symmetrically in flight they act as speed brakes. Because they change lift and drag rather than move the airplane about an axis by themselves, spoilers are classed as secondary or auxiliary control surfaces along with flaps, slats and tabs.
Source: FAA-H-8083-31 Aviation Maintenance Technician Handbook (Airframe), Ch. 1 (Spoilers and speed brakes)Report a problem with this question
Practice questions based on the Aviation Mechanic Airman Certification Standards (FAA-S-ACS-1), 14 CFR parts 43, 65, and 91, and the FAA Aviation Maintenance Technician Handbook—Airframe (FAA-H-8083-31). This site is not affiliated with or endorsed by the Federal Aviation Administration. This bank covers the AIRFRAME written test only; the General and Powerplant written tests and the oral and practical tests are separate. Torque values, cable tensions, inflation pressures, servicing quantities, wear limits, and repair criteria always come from the manufacturer's current maintenance data, the structural repair manual, and the applicable airworthiness directives — never from a practice test. Confirm current eligibility and testing requirements with the FAA before you test. About the A&P mechanic certificate →