FAA Airframe Mechanic Written Exam — Questions and Answers

Question 1: When rigging a conventional aircraft control system, what document establishes the correct cable tension values?

The aircraft's Type Certificate Data Sheet
The manufacturer's maintenance or service manual (Correct answer)
FAA Advisory Circular AC 43.13-1B
The aircraft's weight and balance report

Correct answer: The manufacturer's maintenance or service manual

Cable tension specifications are aircraft-specific and must be obtained from the manufacturer's maintenance or service manual.

Question 2: Before checking the wing dihedral and incidence angles during a rigging check, what is the most critical preparatory step?

Retracting the landing gear and placing the aircraft on tail stands.
Setting all flight controls and trim tabs to their neutral positions.
Leveling the aircraft both longitudinally and laterally according to the maintenance manual. (Correct answer)
Ensuring the fuel tanks are completely full to establish a baseline weight.

Correct answer: Leveling the aircraft both longitudinally and laterally according to the maintenance manual.

All airframe alignment and rigging measurements must be taken from a specific, known reference plane. The aircraft must first be leveled according to the manufacturer's specific instructions and leveling points (often using a spirit level or plumb bob). Performing these checks on an un-level aircraft will result in inaccurate measurements and improper rigging.

Question 3: An aircraft's electrical schematic shows a device that uses a small current flowing through a coil to electromagnetically close a set of contacts, allowing a much larger current to flow to a high-power component like a starter motor. Which device performs this function?

A circuit breaker
A diode
A resistor
A relay (Correct answer)

Correct answer: A relay

A relay is an electromechanical switch that uses a small control current to activate an electromagnet, which in turn closes contacts to control a separate, high-power circuit. This allows for remote switching and reduces the need for heavy-gauge wiring to the cockpit controls.

Question 4: In the context of an aircraft sheet metal repair, what is the primary function of a joggle?

To create a decorative finish on the repair patch.
To allow one sheet of metal to overlap another while maintaining a flush surface. (Correct answer)
To increase the thickness of the material for added strength.
To provide a space for electrical wiring to pass through.

Correct answer: To allow one sheet of metal to overlap another while maintaining a flush surface.

A joggle is an offset bend formed in a piece of sheet metal. Its purpose is to allow a mating part, such as a repair patch or another skin panel, to overlap it without creating a step. This maintains the aerodynamic smoothness of the aircraft's surface by creating a flush joint.

Question 5: When removing a solid shank rivet, the drill bit diameter used should be:

Equal to the rivet head diameter
Slightly larger than the rivet shank to ease removal
Slightly smaller than the rivet shank diameter to avoid enlarging the hole (Correct answer)
Equal to the rivet shank diameter

Correct answer: Slightly smaller than the rivet shank diameter to avoid enlarging the hole

Drilling slightly smaller than the shank diameter allows the rivet head to be punched off cleanly without enlarging the hole for the replacement rivet.

Question 6: What is the key difference between a hydraulic system pressure relief valve and a pressure regulator?

A relief valve is manually operated, whereas a pressure regulator is fully automatic.
A relief valve regulates normal system pressure, while a regulator is for emergency overpressure events.
A regulator is installed in the return line to the reservoir, while a relief valve is in the pressure line.
A relief valve is a safety device to prevent over-pressurization, while a regulator maintains a specific downstream pressure. (Correct answer)

Correct answer: A relief valve is a safety device to prevent over-pressurization, while a regulator maintains a specific downstream pressure.

A pressure relief valve is primarily a safety device that opens only when system pressure exceeds a preset limit, venting excess pressure to prevent damage. A pressure regulator is designed to continuously maintain a specific, controlled pressure in a portion of the system that is lower than the main system pressure.

Question 7: When performing a sheet metal repair, what is the primary purpose of stop-drilling the ends of a crack?

To mark the location of the crack for inspection.
To create a hole for a temporary fastener.
To relieve stress and prevent the crack from propagating. (Correct answer)
To provide a starting point for a saw or file.

Correct answer: To relieve stress and prevent the crack from propagating.

Stop-drilling involves drilling a small hole at the tip of a crack. This technique distributes the stress concentration from the sharp point of the crack over the larger area of the drilled hole, which effectively blunts the crack and prevents it from spreading further under load and vibration.

Question 8: An aircraft's aluminum skin shows signs of fine, worm-like lines of corrosion products beneath the paint film, particularly in a high-humidity environment. Which type of corrosion is most likely present?

Intergranular corrosion
Pitting
Filiform corrosion (Correct answer)
Stress corrosion cracking

Correct answer: Filiform corrosion

Filiform corrosion is characterized by its worm-like appearance as it forms tunnels of corrosion products under the paint. It is common on painted aluminum surfaces that are exposed to high humidity.

Question 9: A technician observes paint lines on an aircraft's tire and wheel rim that are no longer aligned. What is the primary purpose of these 'creep marks'?

To provide a visual reference for tire tread wear.
To indicate the correct valve stem position for tube alignment.
To show if the tire has slipped on the wheel rim. (Correct answer)
To mark the proper location for attaching wheel balance weights.

Correct answer: To show if the tire has slipped on the wheel rim.

Creep marks, or slippage marks, are painted lines that extend from the wheel rim to the tire sidewall. Their purpose is to provide a visual indication of whether the tire has rotated or 'slipped' on the wheel rim. This is especially critical for tubed tires, as significant slippage can shear the valve stem off the inner tube, leading to a rapid loss of tire pressure.

Question 10: Which tool is used to measure the diameter of a drilled hole to ensure it is the correct size for the rivet being installed?

Pin gauges or 'go/no-go' gauges (Correct answer)
Micrometer caliper
Telescoping gauge and micrometer
Vernier caliper only

Correct answer: Pin gauges or 'go/no-go' gauges

Pin gauges (go/no-go gauges) quickly verify that drilled holes fall within the acceptable tolerance range for the specified rivet diameter.

Question 11: What are the principal structural members of a wing that run from the root to the tip and carry most of the bending loads?

Spars (Correct answer)
Ribs
Stringers
Formers

Correct answer: Spars

Spars are the main spanwise structural members of the wing. They are designed to take the primary bending and shear loads generated by lift forces during flight.

Question 12: What is the primary function of a Constant Speed Drive (CSD) connected to an engine-driven AC generator?

To cool the generator using a dedicated oil system.
To convert the variable engine RPM into a constant generator RPM. (Correct answer)
To provide over-voltage protection for the electrical bus.
To act as a clutch, allowing the generator to be disengaged.

Correct answer: To convert the variable engine RPM into a constant generator RPM.

AC generators must rotate at a precise, constant speed to produce alternating current at a stable frequency (typically 400 Hz). A Constant Speed Drive is a hydro-mechanical transmission that takes the variable RPM from the engine's accessory gearbox and outputs a constant RPM to drive the generator.

Question 13: Which type of hydraulic fluid is known for its fire-resistant properties and is commonly used in modern commercial transport aircraft?

Synthetic hydrocarbon-based fluid (e.g., MIL-H-83282)
Mineral-based fluid (e.g., MIL-H-5606)
Phosphate ester-based fluid (e.g., Skydrol) (Correct answer)
Vegetable-based fluid

Correct answer: Phosphate ester-based fluid (e.g., Skydrol)

Phosphate ester-based hydraulic fluids, such as Skydrol, are widely used in commercial aviation because of their excellent fire-resistant properties, which enhance safety in high-temperature environments like those found near engines and braking systems.

Question 14: When rigging pushrods, what condition should be avoided to prevent binding or misalignment forces on the rod-end bearings?

Allowing the pushrod to carry side loads due to misalignment (Correct answer)
Installing the pushrod with offset rod-end threads
Connecting the pushrod at the inboard end of a bellcrank
Setting the pushrod length longer than specified

Correct answer: Allowing the pushrod to carry side loads due to misalignment

Rod-end (rod end) bearings are designed for axial loads; side loads from misalignment cause premature wear and possible failure.

Question 15: What is the purpose of the aircraft fire detection system?

To detect and alert fire hazards (Correct answer)
To control engine power.
To manage in-flight communication.
To monitor the fuel efficiency.

Correct answer: To detect and alert fire hazards

The primary purpose of an aircraft fire detection system is to quickly identify the presence of fire or overheating in critical areas like engine compartments or cargo bays. Upon detection, it triggers an alarm to alert the flight crew. This allows for immediate action, such as activating fire suppression systems, to prevent catastrophic damage and ensure the safety of the aircraft and its occupants.

Question 16: During final rigging check of a manual flight control system, the mechanic applies force to deflect the aileron and then releases it. The aileron should:

Vibrate briefly and then center automatically via the trim tab
Return to neutral only when the opposite aileron is deflected
Return to the neutral position and remain there without binding or excessive friction (Correct answer)
Stay in the deflected position due to control lock friction

Correct answer: Return to the neutral position and remain there without binding or excessive friction

After deflection, flight controls must return to neutral under system forces (springs, weight, aerodynamic loads) and remain there without binding, sticking, or excessive breakout force.

Question 17: A technician is performing maintenance on a nickel-cadmium (Ni-Cad) battery and observes a white, powdery residue on the battery case near the cell vents. This is most often caused by:

Electrolyte reacting with lead-acid fumes from a nearby battery.
Electrolyte spewage due to overcharging or excessive heat. (Correct answer)
Normal outgassing during a deep discharge cycle.
The battery freezing in extremely low ambient temperatures.

Correct answer: Electrolyte spewage due to overcharging or excessive heat.

The white, powdery substance found on Ni-Cad batteries is potassium carbonate. It forms when the potassium hydroxide electrolyte is spewed from the cells, often due to overcharging or high temperatures, and subsequently reacts with carbon dioxide in the air.

Question 18: What material is commonly used for flexible fuel hose connections in certified aircraft fuel systems?

Unlined steel braided hose
Teflon-lined synthetic rubber hose (Correct answer)
Aluminum rigid tubing
Copper tubing

Correct answer: Teflon-lined synthetic rubber hose

Teflon-lined synthetic rubber hoses are used for flexible fuel connections because Teflon resists aviation fuel degradation and the rubber provides flexibility to absorb vibration.

Question 19: 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 20: What does a fuel system pressure check after maintenance involve?

Verifying the fuel selector moves smoothly through all positions
Checking fuel tank quantity with all caps removed
Pressurizing the fuel system to specified limits and inspecting all connections, seals, and fittings for leaks (Correct answer)
Running the engine at full power while monitoring fuel flow gauges

Correct answer: Pressurizing the fuel system to specified limits and inspecting all connections, seals, and fittings for leaks

A fuel system pressure check involves pressurizing the system to manufacturer-specified limits and carefully inspecting all connections, seals, lines, and fittings for any sign of leakage.

Question 21: What is the purpose of checking control surface balance (mass balance) during assembly?

To confirm the hinge bolts are properly torqued
To verify that the surface is aerodynamically efficient at cruise speed
To prevent flutter by ensuring the control surface center of gravity is at or forward of the hinge line (Correct answer)
To measure the surface's maximum deflection angle

Correct answer: To prevent flutter by ensuring the control surface center of gravity is at or forward of the hinge line

Mass balancing positions the control surface CG at or ahead of the hinge line, which suppresses aerodynamic flutter that could lead to structural failure.

Question 22: Which regulatory reference would a mechanic consult to determine if a specific airframe repair is classified as major or minor?

AC 43.13-2B
14 CFR Part 65.81
14 CFR Part 91.409
14 CFR Part 43, Appendix A (Correct answer)

Correct answer: 14 CFR Part 43, Appendix A

14 CFR Part 43, Appendix A defines major alterations, major repairs, and minor repairs and alterations for airframes and other aircraft systems.

Question 23: What is the significance of an asterisk (*) notation on an FAA-approved aircraft weight and balance report?

It indicates a discrepancy requiring immediate maintenance action
It denotes items that are included in the licensed empty weight (Correct answer)
It marks fuel quantities that are unusable
It indicates the item is optional equipment

Correct answer: It denotes items that are included in the licensed empty weight

Items marked with an asterisk on a weight and balance report are typically included in the licensed empty weight calculation.

Question 24: What is the purpose of a fuel cross-feed system on a multi-engine aircraft?

To allow fuel flow from one wing tank to the other or to feed any engine from any tank (Correct answer)
To return excess fuel to the main tank after engine shutdown
To remove dissolved air from fuel lines
To boost fuel pressure during high-power takeoff

Correct answer: To allow fuel flow from one wing tank to the other or to feed any engine from any tank

A cross-feed system allows fuel to be transferred between tanks for lateral balance or to supply any engine from the opposite wing tank in the event of a fuel pump failure.

Question 25: To verify the integrity of an electrical bond between an equipment rack and the aircraft structure, a technician should use a multimeter to measure for:

the capacitance of the bonding strap.
a specific AC voltage.
a very low resistance. (Correct answer)
the absence of continuity.

Correct answer: a very low resistance.

Electrical bonding ensures that all conductive parts of the aircraft are at the same electrical potential. A proper bond provides a path of least resistance for fault currents, lightning strikes, and static discharge. A test of a good bond is a measurement of very low resistance (typically in the milliohm range) between the two points.

Question 26: Which document specifies the required flight control surface travel limits for a certificated aircraft?

The pilot's operating handbook (POH) only
CFR Part 23 alone
The applicable Aircraft Maintenance Manual (AMM) (Correct answer)
AC 43.13-1B

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 27: Which of the following cable materials is NOT recommended for primary flight control systems due to its susceptibility to corrosion?

Both B and C (Correct answer)
Stainless steel cable (MIL-W-83420)
Galvanized carbon steel cable
Carbon steel cable without coating

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 28: When inspecting a riveted skin splice for serviceability, which condition would require immediate repair?

A manufactured head with 2° of tilt from perpendicular
A crack emanating from a rivet hole (Correct answer)
A shop head that is 5% smaller than the nominal driven diameter
A rivet with slight surface corrosion on the manufactured head

Correct answer: A crack emanating from a rivet hole

A crack emanating from a rivet hole is a critical defect that requires immediate repair because it will grow under fatigue loading.

Question 29: What type of fuel is typically used in jet engines?

Diesel.
Electric charge.
Gasoline.
Jet A or Jet A-1 fuel (Correct answer)

Correct answer: Jet A or Jet A-1 fuel

Jet A and Jet A-1 are specific types of kerosene-based fuels formulated to meet the stringent requirements of turbine engines used in jet aircraft. These fuels possess properties like appropriate viscosity, energy content, and freezing points that are critical for efficient combustion and reliable operation across various altitudes and temperatures. They are distinct from fuels used in piston engines like gasoline or diesel.

Question 30: According to 14 CFR Part 43, Appendix A, which of the following is considered a major alteration to an aircraft's hydraulic system?

Changes to the basic design of the hydraulic system. (Correct answer)
Replacing a hydraulic hose with an identical, approved part.
Servicing a hydraulic accumulator with nitrogen.
Replacing the seals in a brake master cylinder.

Correct answer: Changes to the basic design of the hydraulic system.

14 CFR Part 43, Appendix A defines major alterations. Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems are specifically listed as major alterations. Simple component replacements or servicing are generally considered maintenance or minor repairs.

Question 31: Fluid in an aircraft hydraulic reservoir is maintained above the minimum level primarily to:

Prevent pump cavitation and allow for thermal expansion of fluid (Correct answer)
Keep the reservoir weight balanced
Maintain correct center of gravity
Cool the hydraulic pump externally

Correct answer: Prevent pump cavitation and allow for thermal expansion of fluid

Adequate fluid level prevents the pump from drawing air (cavitation) and provides volume for fluid that expands when heated during operation.

Question 32: What is the primary function of a static inverter in an aircraft electrical system?

To convert AC power to DC power for battery charging.
To regulate the voltage output of the main generators.
To convert DC power from the aircraft battery or DC bus to AC power. (Correct answer)
To provide a stable source of DC power for emergency lighting.

Correct answer: To convert DC power from the aircraft battery or DC bus to AC power.

A static inverter is a solid-state electronic device that converts direct current (DC) into alternating current (AC). This allows DC power from sources like the aircraft's batteries or transformer-rectifier units to be used for instruments and avionics that require AC power, often as a primary or emergency backup source.

Question 33: When assembling a modular aircraft fuselage, what is typically used to ensure proper alignment of major structural assemblies before final fastener installation?

Alignment fixtures or assembly jigs specified by the manufacturer (Correct answer)
Laser levels and plumb bobs from adjacent structure
Center-of-gravity measurement equipment
Adjustable clamps and mechanic's judgment

Correct answer: Alignment fixtures or assembly jigs specified by the manufacturer

Manufacturer-specified assembly jigs and fixtures ensure that major structural components are held in the correct position and alignment during assembly.

Question 34: After rigging a rudder control system, the rudder deflects 25° right but only 20° left. What is the most likely cause?

The rudder stop on the left side is set too close, or the left cable is over-tensioned relative to the right (Correct answer)
The rudder hinge bolts are too tight on the left side
The vertical fin is misaligned to the fuselage
The cable on the right side has too many nicks

Correct answer: The rudder stop on the left side is set too close, or the left cable is over-tensioned relative to the right

Asymmetric deflection typically results from an incorrectly set travel stop on the low-travel side or unequal cable tension causing the neutral position to be offset.

Question 35: Stress corrosion cracking in high-strength aluminum alloys is most likely to initiate when:

The alloy is exposed to salt spray during ground operations
Sustained tensile stress acts on the material in a corrosive environment (Correct answer)
The material is heated above its recrystallization temperature
Compressive residual stresses are introduced by shot peening

Correct answer: Sustained tensile stress acts on the material in a corrosive environment

Stress corrosion cracking requires the simultaneous combination of sustained tensile stress and a corrosive environment to initiate and propagate.

Question 36: A 'stop-drill' is used in sheet metal repair to:

Halt crack propagation by removing the stress concentration at the crack tip (Correct answer)
Align repair patches during installation
Remove old rivets from damaged panels
Create holes for new rivets

Correct answer: Halt crack propagation by removing the stress concentration at the crack tip

Stop-drilling places a hole at the end of a crack to redistribute stress and prevent the crack from continuing to grow.

Question 37: In a damage-tolerant aircraft structure, what is the purpose of fracture mechanics-based inspection intervals?

To eliminate cracks before they can form
To certify that no fatigue damage exists in the fleet
To ensure cracks are detected and repaired before reaching critical size (Correct answer)
To identify structures that need immediate replacement

Correct answer: To ensure cracks are detected and repaired before reaching critical size

Fracture mechanics sets inspection intervals so that any crack growing from the assumed initial flaw size will be found and repaired before it reaches the critical size that causes failure.

Question 38: When using dye penetrant inspection on an aluminum wing spar, which step must be performed before applying the penetrant?

Clean and degrease the surface thoroughly (Correct answer)
Heat the part to 200°F to open any cracks
Apply a zinc chromate primer as a base coat
Apply developer first to draw out existing contamination

Correct answer: Clean and degrease the surface thoroughly

The surface must be cleaned and degreased before penetrant application to allow the penetrant to enter any surface discontinuities.

Question 39: What is the primary function of a centering cam in a retractable nose landing gear system?

To dampen nose wheel shimmy during taxi operations.
To absorb landing shock forces through the shock strut.
To engage the nose wheel steering system after landing.
To align the nose wheel in the fore-and-aft direction before retraction. (Correct answer)

Correct answer: To align the nose wheel in the fore-and-aft direction before retraction.

A centering cam is a mechanical device within the nose gear shock strut that ensures the nose wheel is aligned straight (fore-and-aft) before it is retracted into the wheel well. As the strut extends fully after takeoff (when the aircraft's weight is off the wheels), two cams, one upper and one lower, engage to lock the wheel in the centered position, preventing damage to the aircraft structure during retraction.

Question 40: What is the purpose of using a dimpling operation in sheet metal work?

To test material hardness before riveting
To increase sheet thickness at rivet locations
To create a countersunk recess in thin sheets that cannot be machine countersunk (Correct answer)
To mark drill locations before punching

Correct answer: To create a countersunk recess in thin sheets that cannot be machine countersunk

Dimpling forms a countersunk recess in sheet metal that is too thin to machine countersink, allowing flush rivet installation.

Question 41: When checking flight control surface travel with a protractor, where is the protractor typically placed?

On the control column or stick
On the adjacent fixed structure
On the top surface of the control surface at the specified reference location (Correct answer)
On the spar of the control surface

Correct answer: On the top surface of the control surface at the specified reference location

The protractor (or inclinometer) is placed on the top surface of the control surface at the reference station specified in the maintenance manual.

Question 42: What condition exists when a rivet exhibits a 'smile' or crescent-shaped crack in the manufactured head after driving?

The rivet was driven with an improperly fitted rivet set
The material is too hard for solid shank rivets
The rivet hole was undersize causing head fracture
The rivet was overdriven (too many hammer blows) (Correct answer)

Correct answer: The rivet was overdriven (too many hammer blows)

A crescent crack in the rivet head is a sign of overdriving; the excessive deformation stress cracks the head, requiring the rivet to be removed and replaced.

Question 43: What type of fuel system is used on most high-wing general aviation aircraft with gravity-fed carburetor engines?

Pressure injection system with electric pumps
Gravity-feed system relying on fuel head pressure from the tanks (Correct answer)
Centrifugal pump system driven by the accessory gearbox
Bladder-cell system pressurized by engine bleed air

Correct answer: Gravity-feed system relying on fuel head pressure from the tanks

High-wing aircraft with carbureted engines often use a gravity-feed system where fuel flows by gravity from the wing tanks above the engine without requiring a pump.

Question 44: What is 'misfueling' and what is a common serious consequence?

Putting the wrong type of fuel in an aircraft, which can cause engine failure or serious damage (Correct answer)
Overfilling a tank beyond capacity, causing only minor fuel spillage
Failing to refuel before flight, leading to fuel starvation in flight
Mixing two approved brands of the same fuel type, with no safety consequence

Correct answer: Putting the wrong type of fuel in an aircraft, which can cause engine failure or serious damage

Misfueling means adding the wrong fuel type (e.g., Jet-A into an avgas piston engine), which can cause immediate engine failure, detonation, or serious internal engine damage.

Question 45: What safety procedure must be performed before opening an aircraft fuel system for maintenance?

Pressurize the fuel system to identify leaks first
Bond and ground the aircraft to prevent static discharge and follow all fuel safety precautions (Correct answer)
Apply preservative oil to all fuel fittings before disconnecting
Disconnect only the aircraft battery to prevent sparks

Correct answer: Bond and ground the aircraft to prevent static discharge and follow all fuel safety precautions

Aircraft must be properly bonded and grounded before fuel system maintenance to prevent static electricity ignition of fuel vapors, and all applicable fuel safety precautions must be followed.

Question 46: What is the minimum number of exposed threads that must show beyond a castle (castellated) nut after torquing, before installing a cotter pin?

No thread needs to show; the cotter pin goes through the shank only
At least one full thread must be visible beyond the nut face (Correct answer)
The threads must be flush with the nut face
Three full threads must protrude beyond the nut

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 47: What color coding identifies MIL-PRF-5606 hydraulic fluid?

Red (Correct answer)
Green
Purple
Blue

Correct answer: Red

MIL-PRF-5606 is a mineral-based hydraulic fluid identified by its red color.

Question 48: The K-factor in sheet metal bending is used to determine:

The required die width for a press brake operation
The minimum bend radius for a given material and thickness
The maximum allowable springback angle
The location of the neutral axis within the material thickness (Correct answer)

Correct answer: The location of the neutral axis within the material thickness

The K-factor defines the position of the neutral axis within the material thickness, which determines accurate bend allowance calculations.

Question 49: During a sheet metal repair, when must a doubler be used in addition to the filler patch?

Only when the original skin thickness is less than 0.032 inches
Whenever the damaged area exceeds the allowable limits for a simple filler patch (Correct answer)
When more than three rivets in a row must be replaced
On all repairs to pressurized fuselage skin regardless of damage size

Correct answer: Whenever the damaged area exceeds the allowable limits for a simple filler patch

A doubler is required when damage exceeds the limits for a simple filler patch, providing the additional material needed to restore original structural strength.

Question 50: During aileron rigging, the left aileron is found to be 2° high (trailing edge up) and the right aileron is 2° low (trailing edge down) with the control wheel centered. This condition indicates:

The ailerons are improperly balanced
Correct rigging — differential travel is intentional
A bent or misrigged aileron bellcrank
The aileron cables have unequal tension (Correct answer)

Correct answer: The aileron cables have unequal tension

With the control wheel centered, both ailerons should be in the neutral (faired) position; unequal positions with centered controls indicate unequal cable tension.

Question 51: A ground-adjustable tab differs from a trim tab in that it:

Can be adjusted in flight by the pilot using a cockpit control
Moves opposite to the main control surface to reduce hinge moment
Is adjusted only on the ground and cannot be moved in flight (Correct answer)
Is driven by a separate hydraulic actuator

Correct answer: Is adjusted only on the ground and cannot be moved in flight

Ground-adjustable tabs are bent to a fixed position by maintenance personnel before flight and cannot be repositioned by the pilot from the cockpit.

Question 52: What is the purpose of fuel tank baffles installed inside aircraft fuel tanks?

To allow the fuel quantity transmitter to read accurately
To prevent fuel surge and maintain fuel outlet coverage during flight maneuvers (Correct answer)
To increase internal fuel tank pressure during climb
To filter large debris before fuel reaches the boost pump

Correct answer: To prevent fuel surge and maintain fuel outlet coverage during flight maneuvers

Fuel tank baffles are internal partitions that prevent fuel from surging away from the outlet during maneuvers, ensuring continuous uninterrupted fuel flow to the engine.

Question 53: In a pneumatic system, what is the primary function of a moisture separator or water trap?

To remove water vapor and contaminants from the compressed air. (Correct answer)
To lubricate the pneumatic components.
To cool the compressed air before it enters the system.
To increase the pressure of the air in the system.

Correct answer: To remove water vapor and contaminants from the compressed air.

Moisture separators are critical components in pneumatic systems designed to remove water vapor, which naturally condenses out of compressed air. This prevents corrosion of internal components, freezing at high altitudes, and contamination of the system.

Question 54: 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
Reported to the FAA before further flight
Replaced immediately (Correct answer)
Monitored at each 100-hour inspection

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 55: When riveting near a formed flange or edge, which direction should the bucking bar force be applied relative to the rivet shank?

At the angle matching the countersink angle
At a 45° angle to maximize driven head spread
Parallel to the rivet shank (axially) (Correct answer)
Perpendicular to the rivet shank

Correct answer: Parallel to the rivet shank (axially)

The bucking bar must be held perpendicular to the sheet surface and aligned axially with the rivet shank to form a properly shaped driven head.

Question 56: When performing a visual inspection of flight control cables, which condition would most likely require replacement of the cable?

Cable tension 5% below the specified value
Presence of cable lubricant on the outer strands
Slight discoloration of the cable outer strands
Three broken wires in one lay of a 7×19 cable (Correct answer)

Correct answer: Three broken wires in one lay of a 7×19 cable

AC 43.13-1B states that cables with three or more broken wires in one lay length are typically cause for rejection and replacement.

Question 57: In a pneumatic system, a desiccant is used to:

Increase air pressure
Filter particulate matter
Remove moisture from compressed air (Correct answer)
Regulate airflow rate

Correct answer: Remove moisture from compressed air

Desiccants absorb moisture from compressed air to prevent corrosion and ice formation within pneumatic components.

Question 58: What is the function of a torque tube in an aircraft control system?

Absorb vibration between the engine and airframe
Transmit rotational motion to move control surfaces (Correct answer)
Connect the rudder pedals to the nose wheel
Measure and limit control cable tension

Correct answer: Transmit rotational motion to move control surfaces

A torque tube transmits rotational (torsional) loads to actuate control surfaces such as flaps or ailerons.

Question 59: After an aileron has been repainted, it must be rebalanced. Which of the following is the most critical reason for this procedure?

To prevent the onset of high-frequency control surface flutter. (Correct answer)
To ensure the new paint is properly cured and bonded to the surface.
To verify the correct range of motion for the control surface.
To reduce the amount of force the pilot must exert on the controls.

Correct answer: To prevent the onset of high-frequency control surface flutter.

Adding paint adds weight to the control surface. If this weight is not distributed correctly relative to the hinge line, it can change the surface's center of gravity. An improperly balanced control surface is highly susceptible to flutter, a rapid and destructive oscillation caused by the interaction of aerodynamic, inertial, and elastic forces, which can lead to catastrophic structural failure.

Question 60: What is the term for the tendency of a long, slender column to buckle sideways when subjected to compressive loads?

Plastic deformation
Stress relaxation
Euler buckling (Correct answer)
Creep

Correct answer: Euler buckling

Euler buckling describes the instability of a slender column under axial compression, where it deflects laterally rather than compressing uniformly.

Question 61: What happens to mixture requirements as altitude increases in a non-turbocharged reciprocating engine?

Mixture must be leaned because air density decreases (Correct answer)
More fuel is required to maintain the correct ratio
Altitude has no effect on mixture setting
Mixture must be enriched because fuel vaporizes faster

Correct answer: Mixture must be leaned because air density decreases

As altitude increases, air density decreases so less air enters the engine, requiring the mixture to be leaned to maintain the proper fuel-air ratio.

Question 62: What is the primary reason that aircraft maintenance manuals provide a temperature/tension chart for rigging flight control cables?

To determine the correct size of safety wire to use on the turnbuckles.
To compensate for the different thermal expansion rates of the aluminum airframe and the steel cables. (Correct answer)
To prevent corrosion from forming between the cable strands.
To ensure the tensiometer is properly calibrated before use.

Correct answer: To compensate for the different thermal expansion rates of the aluminum airframe and the steel cables.

Aircraft structures, typically made of aluminum alloys, expand and contract at a different rate than the steel control cables when subjected to temperature changes. A temperature/tension chart allows a technician to set the correct cable tension at a given ambient temperature, ensuring that the tension will remain within the specified limits whether the aircraft is on a hot ramp or at high altitude where temperatures are very low.

Question 63: A crack found running parallel to the length of a fuselage stringer is most likely caused by which type of stress?

Torsional stress
Compressive stress
Shear stress
Hoop stress (Correct answer)

Correct answer: Hoop stress

Hoop (circumferential) stress from pressurization acts perpendicular to the fuselage axis, causing cracks that run parallel to longitudinal members.

Question 64: What type of oil is used in most turbine engines?

SAE 30 mineral oil
Synthetic ester-based oil (Correct answer)
Ashless dispersant mineral oil
Automotive multi-viscosity oil

Correct answer: Synthetic ester-based oil

Turbine engines require synthetic ester-based oils that withstand the extreme temperatures and provide adequate lubrication at high altitudes.

Question 65: Which of the following is a key component of safety procedures?

Passenger comfort protocols.
In-flight entertainment management.
Cost reduction strategies.
Emergency response and evacuation procedures (Correct answer)

Correct answer: Emergency response and evacuation procedures

Emergency response and evacuation procedures are a critical component of aviation safety protocols. These detailed plans outline the specific actions to be taken by crew and passengers in various emergency situations, such as fires, medical emergencies, or forced landings. Practicing and understanding these procedures is essential to minimize harm and ensure an organized and safe outcome during unforeseen events.

Question 66: A technician is performing a static balance check on an aileron that has just been repainted. The procedure involves supporting the aileron on a knife-edge fixture at its hinge line. Which of the following conditions indicates the aileron is properly balanced?

The leading edge slowly drops until it rests on the fixture.
The aileron remains in a horizontal position or exhibits a slight nose-down tendency. (Correct answer)
The aileron oscillates for several seconds before settling with the trailing edge down.
The trailing edge consistently rises to a 15-degree angle.

Correct answer: The aileron remains in a horizontal position or exhibits a slight nose-down tendency.

Proper static balance requires the control surface's center of gravity (CG) to be at or slightly ahead of the hinge line. When placed on a knife-edge at the hinge line, a balanced surface will remain horizontal or show a slight tendency to be nose-down. A trailing-edge-heavy condition (underbalance) is undesirable as it can lead to control surface flutter at high speeds.

Question 67: What is 'corrosion' in the context of aircraft metals?

Fatigue cracking from repeated stress cycles
Deformation of metal under sustained load
Microscopic cracking caused by hydrogen embrittlement only
Electrochemical deterioration of metal by reaction with the environment (Correct answer)

Correct answer: Electrochemical deterioration of metal by reaction with the environment

Corrosion is the electrochemical deterioration of metal through chemical reaction with moisture, oxygen, or other environmental agents.

Question 68: During a ground maintenance check on a retractable-gear aircraft, a technician attempts to raise the landing gear using the cockpit selector switch, but the gear does not retract. Which safety device is most likely preventing the gear retraction?

The downlock mechanism.
The squat switch (or weight-on-wheels switch). (Correct answer)
The hydraulic bypass valve.
The gear-up indicator light.

Correct answer: The squat switch (or weight-on-wheels switch).

A squat switch, also known as a weight-on-wheels switch, is a safety device that prevents accidental retraction of the landing gear when the aircraft is on the ground. It senses when the aircraft's weight is compressing the landing gear struts and opens an electrical circuit to the retraction mechanism, making it impossible to raise the gear.

Question 69: What is the primary function of a turnbuckle in an aircraft flight control cable system?

To provide a quick-disconnect point for cable removal.
To dampen vibrations transmitted along the control cable.
To allow for the adjustment of cable length and tension. (Correct answer)
To act as a fusible link that fails under excessive loads.

Correct answer: To allow for the adjustment of cable length and tension.

A turnbuckle is a device consisting of a barrel with internal screw threads at both ends (one right-hand and one left-hand) that connects to threaded cable terminals. By rotating the barrel, the terminals are drawn together or pushed apart, allowing for precise adjustments to the length and, therefore, the tension of the control cable.

Question 70: During wing-to-fuselage assembly on a high-wing strut-braced aircraft, which alignment parameter is checked using a plumb bob?

Dihedral angle at the wingtip
Angle of incidence at the wing root
Wing sweep angle
Lateral level of the wing root attachment relative to the fuselage centerline (Correct answer)

Correct answer: Lateral level of the wing root attachment relative to the fuselage centerline

A plumb bob dropped from the wing root fitting verifies that both sides are laterally level and symmetrical relative to the fuselage datum centerline.

Question 71: Pascal's Law is a fundamental principle governing hydraulic systems. Which of the following statements best describes this law?

For every action in a fluid system, there is an equal and opposite reaction.
Fluid pressure is directly proportional to the fluid's velocity.
Pressure applied to a confined fluid is transmitted undiminished to every portion of the fluid and the walls of the containing vessel. (Correct answer)
The force exerted by a fluid is equal to its mass times its acceleration.

Correct answer: Pressure applied to a confined fluid is transmitted undiminished to every portion of the fluid and the walls of the containing vessel.

Pascal's Law states that when pressure is applied to a confined, incompressible fluid, the pressure is transmitted equally in all directions throughout the fluid. This principle allows hydraulic systems to multiply force.

Question 72: What is the function of a jury strut on a semi-cantilever wing?

Prevents the interplane strut from bowing under compression loads (Correct answer)
Connects the wing leading edge to the forward fuselage
Transfers fuel load to the center section
Carries the primary bending load from the wing to the fuselage

Correct answer: Prevents the interplane strut from bowing under compression loads

A jury strut braces the interplane or wing strut at its midpoint to prevent bowing or buckling under compressive loads.

Question 73: What is the function of a fuel strainer (gascolator) installed in an aircraft fuel system?

To boost fuel pressure to the carburetor
To control the fuel-to-air mixture ratio
To remove water and debris from fuel before it reaches the engine (Correct answer)
To measure fuel flow rate to the engine

Correct answer: To remove water and debris from fuel before it reaches the engine

A fuel strainer or gascolator filters out water, sediment, and particulate contaminants to protect the carburetor and engine from damage.

Question 74: During a pre-flight inspection, a pilot notices a frayed, flat, braided copper cable connecting the aircraft's elevator to the horizontal stabilizer. What is the primary purpose of this bonding strap?

To transmit control position data to the flight data recorder.
To act as a secondary structural attachment for the control surface.
To provide a low-resistance path for static electricity and fault currents. (Correct answer)
To dampen high-frequency vibration of the control surface.

Correct answer: To provide a low-resistance path for static electricity and fault currents.

Bonding straps (or jumpers) are used to create electrical continuity between all metallic components of the aircraft. Their primary purpose is to provide a path of least resistance for static electricity buildup and electrical fault currents, preventing arcing, sparks, and interference with radio and navigation equipment.

Question 75: A technician is performing a flush patch repair on a pressurized fuselage skin. How should the thickness of the doubler and the filler (patch) relate to the original skin thickness?

The doubler and filler should both be the same thickness as the original skin.
The doubler and filler should both be one gauge thicker than the original skin.
The doubler should be the same thickness, and the filler should be one gauge thinner than the original skin.
The doubler should be one gauge thicker, and the filler should be the same thickness as the original skin. (Correct answer)

Correct answer: The doubler should be one gauge thicker, and the filler should be the same thickness as the original skin.

For a flush patch repair, the filler plug must be of the same gauge and material as the original skin to maintain a smooth surface. The doubler, which provides the structural reinforcement from the inside, should be made of material one gauge heavier (thicker) than the original skin.

Question 76: When visually inspecting a primary structural member of an all-metal aircraft, such as a wing root fitting, which of the following findings would be considered the MOST critical?

A small, smooth-edged dent
A crack originating from a rivet hole (Correct answer)
Light surface oxidation
Chipped or flaking paint

Correct answer: A crack originating from a rivet hole

While all discrepancies must be evaluated, a crack in a primary structural member is the most critical because it represents a failure of the material that can propagate under load, potentially leading to catastrophic failure of the structure. [3, 19] Cracks often start at stress concentration points like rivet holes.

Question 77: When selecting a replacement rivet after removing a damaged rivet, what size rivet should typically be used if the hole is not damaged?

Same diameter but 1/8 inch longer than original
Same diameter and same length as the original (Correct answer)
Next smaller diameter to avoid stressing the hole
Next larger diameter and appropriate length

Correct answer: Same diameter and same length as the original

If the hole is undamaged, the replacement rivet should be the same diameter and appropriate driven length as the original specification.

Question 78: Which material property describes a metal's ability to be drawn into wire without breaking?

Ductility (Correct answer)
Malleability
Brittleness
Elasticity

Correct answer: Ductility

Ductility is the ability of a material to deform plastically under tensile stress, allowing it to be drawn into wire.

Question 79: What is 'chem-milling' used for in aircraft sheet metal fabrication?

Selectively removing material from sheet metal using chemical etching to reduce weight (Correct answer)
Cleaning metal surfaces before welding
Applying corrosion-inhibiting primer to bare metal
Chemically treating rivets before installation

Correct answer: Selectively removing material from sheet metal using chemical etching to reduce weight

Chem-milling uses controlled chemical etching to precisely remove material from selected areas to reduce weight while maintaining structural integrity.

Question 80: When performing a continuity check on a control cable system, a technician finds an open circuit. What does this most likely indicate?

Incorrect cable routing
Moisture in the conduit
A broken or disconnected cable (Correct answer)
Excessive cable tension

Correct answer: A broken or disconnected cable

An open circuit in a cable system continuity check indicates the electrical path is broken, most commonly due to a broken or disconnected wire or cable.

Question 81: An aircraft's retractable landing gear system is equipped with a squat switch, also known as a weight-on-wheels switch. What is the primary function of this switch?

To automatically apply the brakes upon landing.
To control the nose wheel steering system during taxi operations.
To prevent inadvertent retraction of the landing gear while the aircraft is on the ground. (Correct answer)
To illuminate the 'gear down and locked' indicator lights in the cockpit.

Correct answer: To prevent inadvertent retraction of the landing gear while the aircraft is on the ground.

The squat switch is a safety device that opens an electrical circuit when the weight of the aircraft is on the landing gear, preventing power from reaching the gear retraction motor. This ensures the gear cannot be raised while the aircraft is on the ground.

Question 82: How often must fuel strainers and filters be inspected and cleaned according to FAA regulations?

Once per year during the annual inspection only
Only when a fuel system malfunction is detected
At each 100-hour or annual inspection and per manufacturer's maintenance schedule (Correct answer)
Every 500 hours regardless of manufacturer guidance

Correct answer: At each 100-hour or annual inspection and per manufacturer's maintenance schedule

Fuel strainers and filters must be inspected and cleaned at each 100-hour or annual inspection, and at any additional intervals specified by the aircraft manufacturer's maintenance manual.

Question 83: A pilot reports a violent, uncontrolled, side-to-side oscillation of the nose wheel during takeoff and landing rolls. Which of the following conditions is the most likely cause?

Hydraulic fluid cavitation in the brake lines.
A malfunctioning centering cam.
Nose wheel shimmy. (Correct answer)
An over-inflated nose wheel tire.

Correct answer: Nose wheel shimmy.

The condition described is a classic symptom of nose wheel shimmy. This is a rapid, uncontrolled side-to-side oscillation that can be caused by several factors, including worn torque link bushings, an improperly serviced or failing shimmy damper, incorrect tire pressure, or an out-of-balance wheel/tire assembly.

Question 84: A mechanic discovers a crack in an aircraft structure that is NOT listed in the approved repair manual. What is the correct course of action?

Obtain an FAA-approved repair data or DER-approved repair before proceeding (Correct answer)
Stop all work and notify the FAA immediately
Repair the crack using standard riveting practices
Document the crack in the aircraft logbook and continue operation

Correct answer: Obtain an FAA-approved repair data or DER-approved repair before proceeding

Repairs not covered by approved data must be accomplished using FAA-approved data, which may include a Designated Engineering Representative (DER) approval or a Supplemental Type Certificate (STC).

Question 85: Which of the following describes the minimum allowable edge distance for a single row of protruding head rivets in a sheet metal repair?

Two times the rivet shank diameter (Correct answer)
One and a half times the rivet shank diameter
Three times the rivet shank diameter
One times the rivet shank diameter

Correct answer: Two times the rivet shank diameter

According to FAA guidelines (AC 43.13-1B), the minimum edge distance, measured from the center of the rivet hole to the edge of the sheet, should not be less than two times the diameter of the rivet shank for a single row of rivets. This ensures sufficient material strength to prevent the rivet from tearing out the edge of the sheet.

Question 86: What fuel selector valve position is recommended during takeoff and landing on most aircraft with multiple fuel tanks?

Right tank only
Both tanks or the fullest tank (Correct answer)
Left tank only
Off

Correct answer: Both tanks or the fullest tank

Selecting 'Both' or the fullest tank during takeoff and landing ensures maximum fuel availability and minimizes the risk of fuel starvation during these critical flight phases.

Question 87: Aircraft control cables are typically fabricated from which material?

Aluminum alloy 2024-T3
Titanium alloy wire
Galvanized or corrosion-resistant steel (CRES) (Correct answer)
Carbon fiber strands

Correct answer: Galvanized or corrosion-resistant steel (CRES)

Flight control cables are most commonly made from extra-flexible 7×19 or flexible 7×7 carbon steel or corrosion-resistant steel wire rope.

Question 88: Which type of load causes a structural member to twist about its longitudinal axis?

Shear load
Compressive load
Bending load
Torsional load (Correct answer)

Correct answer: Torsional load

Torsional loads cause twisting of a structural member about its longitudinal axis, such as the twisting experienced by a wing during aileron deflection.

Question 89: What is the minimum color specification for safety wire used on aircraft engine hardware?

Any stainless steel wire regardless of diameter
Copper wire, which is the industry standard for most fasteners
Monel or stainless steel wire of the diameter specified in the applicable maintenance manual (Correct answer)
Galvanized steel wire, which is standard for non-critical applications

Correct answer: Monel or stainless steel wire of the diameter specified in the applicable maintenance manual

Safety wire must be made of Monel or stainless steel of the diameter specified in the applicable maintenance manual or standard practice for the application.

Question 90: When safety wiring a turnbuckle using the double-wrap method, what is the generally accepted rule regarding the number of threads that may be exposed at either end of the barrel?

No more than five threads.
At least five threads must be visible for inspection.
Exactly four threads for maximum grip.
No more than three threads. (Correct answer)

Correct answer: No more than three threads.

To ensure adequate thread engagement and structural integrity, standard aviation practice dictates that no more than three threads of the turnbuckle terminal should be exposed outside the barrel after tensioning and before safetying. This ensures the connection is strong enough to handle its rated load.

Question 91: A technician observes that a hydraulic system is operating sluggishly. The system has been serviced recently, and the fluid level in the reservoir is correct. Which of the following is the most likely cause of the issue?

Air has been introduced into the system. (Correct answer)
The system relief valve is stuck open.
The ambient temperature is too high.
The incorrect type of hydraulic fluid was used.

Correct answer: Air has been introduced into the system.

Air in a hydraulic system is compressible, unlike hydraulic fluid. When air is present, the force applied by the pump will first compress the air before moving the hydraulic fluid, leading to a spongy feel and sluggish operation of actuators.

Question 92: What is the purpose of using a dimpling operation instead of countersinking on thin sheet metal?

Dimpling creates a stronger joint than countersinking
Thin sheet does not have enough material depth for a full countersink without knife-edge (Correct answer)
Dimpling is faster than countersinking for production work
Dimpling is required for all flush rivet installations

Correct answer: Thin sheet does not have enough material depth for a full countersink without knife-edge

On thin sheets, countersinking can leave a knife-edge around the hole, so dimpling displaces material rather than removing it.

Question 93: A technician inspecting a multi-disc brake system notices that one of the brakes is dragging after pressure is released. Which of the following is a plausible cause for this issue?

A weak or broken return spring in the brake assembly. (Correct answer)
Creep marks on the tire are misaligned by more than one inch.
Excessive wear on the brake disc's anti-skid sensor.
The use of nitrogen instead of compressed air to service the tire.

Correct answer: A weak or broken return spring in the brake assembly.

Brake drag occurs when the brake pads do not fully retract from the rotor after braking pressure is released. A weak or broken return spring within the brake caliper or piston housing is a common cause, as it fails to provide the necessary force to pull the pistons and pads away from the disc. Other causes can include a jammed piston, contaminated hydraulic fluid, or a malfunctioning master cylinder.

Question 94: Which regulation requires aircraft operators to comply with Airworthiness Directives?

14 CFR 39.7 (Correct answer)
14 CFR 65.81
14 CFR 43.13
14 CFR 91.403

Correct answer: 14 CFR 39.7

14 CFR 39.7 states that no person may operate a product to which an Airworthiness Directive applies except in accordance with the requirements of that AD.

Question 95: What is the purpose of applying sealant between sheet metal faying surfaces in pressurized areas?

To electrically insulate dissimilar metals from each other
To prevent cabin air leaks and provide corrosion protection (Correct answer)
To prevent relative motion and reduce fretting
To improve the strength of the riveted joint

Correct answer: To prevent cabin air leaks and provide corrosion protection

Sealant on faying surfaces in pressurized areas prevents pressurized air from leaking and also inhibits corrosion by excluding moisture from the joint.

Question 96: Which of the following is the primary purpose of a Transformer Rectifier Unit (TRU) in an aircraft electrical system?

To convert 28V DC power to 115V AC power for sensitive instruments
To convert 115V AC power to 28V DC power (Correct answer)
To regulate the frequency of the AC generator output
To step up DC voltage for long-distance transmission

Correct answer: To convert 115V AC power to 28V DC power

A Transformer Rectifier Unit (TRU) is a standard component in aircraft with AC power generation. Its main function is to transform the high-voltage AC (typically 115V, 400Hz) and then rectify it into stable, low-voltage DC (typically 28V) for use by numerous aircraft systems.

Question 97: An aircraft's hydraulic system incorporates an accumulator. What is one of the primary purposes of this component?

To cool the hydraulic fluid as it returns to the reservoir.
To store hydraulic fluid for the pump.
To dampen pressure surges and supplement the pump's output during peak demand. (Correct answer)
To filter contaminants from the hydraulic fluid.

Correct answer: To dampen pressure surges and supplement the pump's output during peak demand.

An accumulator is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure by an external source. Its purposes include dampening pressure fluctuations, supplementing the pump's flow during peak demand (like landing gear operation), and providing a source of emergency pressure if the pump fails.

Question 98: What is the purpose of a servo tab (floating tab) on a large aircraft's control surface?

To provide backup pitch trim in case of elevator failure
To aerodynamically assist control surface movement and reduce pilot effort (Correct answer)
To lock the control surface during ground operations
To limit control surface travel to the maximum structural angle

Correct answer: To aerodynamically assist control surface movement and reduce pilot effort

A servo tab deflects opposite to the desired surface direction, using aerodynamic force to drive the main surface, which reduces the hinge moment the pilot must overcome.

Question 99: Where should a fuel tank sump drain be located to be most effective?

Adjacent to the fuel quantity transmitter
At the midpoint of the tank sidewall for access
At the lowest point where water and sediment accumulate (Correct answer)
At the highest point of the tank to allow air to escape

Correct answer: At the lowest point where water and sediment accumulate

Sump drains are at the lowest point so water, which is denser than fuel, and sediment collect there and can be drained during preflight inspection.

Question 100: In a brushed DC generator, what is the combined function of the commutator and brushes?

To provide a sliding electrical connection and convert the internal AC to external DC. (Correct answer)
To cool the armature windings by providing an air gap.
To vary the magnetic field strength of the stator.
To regulate the generator's output voltage.

Correct answer: To provide a sliding electrical connection and convert the internal AC to external DC.

As the armature rotates, it generates AC internally. The commutator, consisting of segmented copper bars, rotates with the armature. The stationary carbon brushes ride on the commutator, acting as a mechanical rectifier to reverse the current direction every half-turn, resulting in a DC output to the external circuit.

FAA Airframe Mechanic Written Exam

Certifies individuals to inspect, maintain, and repair aircraft airframes, ensuring structural integrity and system functionality in accordance with FAA regulations.

100

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120 min

Time Limit

70%

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