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NCATT AET practice questions

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Question 1Aircraft Fundamentals

In level, unaccelerated flight, which force directly opposes lift?

  1. Drag
  2. Weight Correct answer.
  3. Momentum
  4. Thrust

Explanation

In steady level flight the four forces balance: lift equals weight and thrust equals drag. Lift acts upward, so the force acting directly opposite to it is the aircraft's weight, acting downward through the center of gravity.

Question 2Aircraft Fundamentals

Which primary flight control surface controls rotation about the longitudinal axis?

  1. Rudder
  2. Elevator
  3. Flap
  4. Aileron Correct answer.

Explanation

Ailerons are hinged at the trailing edge of the outer wings and move in opposite directions, producing roll about the longitudinal axis. The elevator controls pitch and the rudder controls yaw.

Question 3Aircraft Fundamentals

A fuselage in which the skin alone carries the primary loads, with no internal longitudinal members, is called:

  1. Truss
  2. Geodetic
  3. Monocoque Correct answer.
  4. Semimonocoque

Explanation

A true monocoque structure carries its primary loads through the outer skin. Semimonocoque designs add stringers and formers to help the skin carry those loads and are far more common in modern aircraft.

Question 4Aircraft Fundamentals

What is the primary purpose of a circuit breaker in an aircraft electrical system?

  1. Step voltage up or down
  2. Convert AC to DC power
  3. Regulate generator output
  4. Protect wiring from overcurrent Correct answer.

Explanation

A circuit breaker opens automatically when current exceeds its rating, protecting wiring and components from overheating. Unlike a fuse, it can be reset after the fault is corrected.

Question 5Aircraft Fundamentals

Which action is required before fueling an aircraft?

  1. Disconnect the battery charger
  2. Open all cabin circuit breakers
  3. Turn on the cabin lighting
  4. Bond the aircraft before fueling Correct answer.

Explanation

Bonding connects the aircraft structure to the fuel source so static charges equalize through a controlled path. Without it, a spark near fuel vapors could cause ignition.

Question 6Aircraft Fundamentals

On an aircraft drawing, a station number typically identifies:

  1. The drawing revision level
  2. A location along a datum Correct answer.
  3. The part's serial number
  4. The material specification

Explanation

Station numbers are measured from a reference datum, usually along the fuselage, so that components can be located consistently during manufacture and repair.

Question 7Aircraft Fundamentals

Which corrosion type appears as a white or gray powdery deposit on unprotected aluminum?

  1. Stress corrosion
  2. Galvanic corrosion
  3. Intergranular corrosion
  4. General surface corrosion Correct answer.

Explanation

Exposed aluminum reacts with oxygen to form a white or gray powdery oxide on the surface. If it is not removed, the attack can progress into pitting and loss of section thickness.

Question 8Aircraft Fundamentals

Which document is the FAA advisory circular that describes acceptable methods, techniques, and practices for aircraft inspection and repair?

  1. Airworthiness Directive
  2. Type certificate data sheet
  3. AC 43.13-1B Correct answer.
  4. FAA Form 337

Explanation

AC 43.13-1B contains the FAA's accepted methods and practices for inspecting and repairing aircraft. It is advisory guidance widely used as the basis for acceptable repairs.

Question 9Aircraft Fundamentals

Pascal's law states that pressure applied to a confined fluid is:

  1. Transmitted undiminished in all directions Correct answer.
  2. Converted entirely into kinetic energy
  3. Absorbed by the system reservoir
  4. Reduced in proportion to fluid volume

Explanation

Pascal's law holds that pressure applied to a confined fluid is transmitted undiminished to every part of the fluid and to the walls of the container. This principle allows a small force on a small piston to produce a large force on a larger piston.

Question 10Aircraft Fundamentals

On most transport-category aircraft, air for cabin pressurization is normally supplied by:

  1. The hydraulic reservoir
  2. The APU bleed only
  3. Engine compressor bleed Correct answer.
  4. The ram air inlet

Explanation

Compressor bleed air is hot and at sufficient pressure to feed the air cycle machines and the pressurization system. The APU can supply bleed air on the ground, but engines are the normal source in flight.

Question 11Aircraft Fundamentals

An aircraft is loaded so that its center of gravity falls aft of the aft limit. What is the primary concern?

  1. Increased fuel consumption
  2. Reduced pitch stability Correct answer.
  3. Reduced takeoff performance
  4. Higher stall speed

Explanation

An aft center of gravity reduces the nose-down moment and can result in marginal or unstable pitch control, and recovery from a stall may become difficult. The aircraft must be loaded within the published CG range.

Question 12Aircraft Fundamentals

Galvanic corrosion is most likely to occur when:

  1. A protective coating is applied to steel
  2. A single metal is exposed to dry air
  3. An alloy is heat treated above its critical range
  4. Dissimilar metals share a common electrolyte Correct answer.

Explanation

When two different metals are joined and wetted by an electrolyte, the more active metal becomes anodic and corrodes preferentially. Preventing moisture from bridging the joint is the main defense.

Question 13Aircraft Fundamentals

Rotation of an aircraft about its lateral axis is called:

  1. Yaw
  2. Bank
  3. Pitch Correct answer.
  4. Roll

Explanation

Pitch is rotation about the lateral, or wing-to-wing, axis and is controlled by the elevator. Roll occurs about the longitudinal axis, and yaw occurs about the vertical axis.

Question 14Aircraft Fundamentals

AC electrical power on most transport aircraft is generated at which frequency?

  1. 1000 Hz
  2. 50 Hz
  3. 400 Hz Correct answer.
  4. 60 Hz

Explanation

Most aircraft AC systems produce 115 V AC at 400 Hz. Higher frequency allows smaller, lighter transformers and motors for a given power rating.

Question 15Aircraft Fundamentals

What is the function of a shimmy damper on a nose landing gear?

  1. Damp nose wheel shimmy Correct answer.
  2. Retract the gear after takeoff
  3. Lock the gear in the down position
  4. Absorb landing impact loads

Explanation

The shimmy damper adds hydraulic damping that resists rapid side-to-side oscillation of the nose wheel during taxi, takeoff, and landing. It does not carry the vertical loads of the aircraft.

Question 16Aircraft Fundamentals

Why must aircraft fuel tanks be vented?

  1. To keep tank pressure near ambient Correct answer.
  2. To drain accumulated water
  3. To allow fuel transfer between tanks
  4. To vent boost pump output

Explanation

Vents keep tank pressure close to ambient as fuel is consumed or as altitude changes. Without venting, a partial vacuum could stop fuel flow or overpressure could damage the tank.

Question 17Aircraft Fundamentals

What is the primary purpose of a trim tab?

  1. Increase the maximum deflection of the control surface
  2. Relieve control forces in steady flight Correct answer.
  3. Provide aerodynamic balance at high airspeeds
  4. Lock the control surface during ground handling

Explanation

A trim tab moves opposite the main control surface, creating a small moment that holds the surface where the pilot wants it. This relieves the control forces the pilot would otherwise have to maintain.

Question 18Aircraft Fundamentals

In a cabin pressurization system, cabin altitude is controlled primarily by:

  1. The inflow of bleed air
  2. The ram air door
  3. The outflow valve position Correct answer.
  4. The cabin compressor speed

Explanation

Conditioned bleed air flows into the cabin continuously, and pressure is regulated by how fast air leaves through the outflow valve. Modulating that valve sets the cabin altitude and rate of change.

Question 19Aircraft Fundamentals

When a bolt is tightened to a specified torque, the torque value is used as an indirect measure of:

  1. Bolt shear strength
  2. Bolt tension Correct answer.
  3. Thread pitch
  4. Grip length

Explanation

Torque stretches the bolt, producing clamping tension. Because friction varies with lubrication and condition, torque is only an approximate indicator of the tension actually achieved.

Question 20Aircraft Fundamentals

Pitot heat is installed to prevent:

  1. Ice on the windshield
  2. Ice in the fuel lines
  3. Ice blocking the pitot tube Correct answer.
  4. Ice on the wing leading edge

Explanation

Ice in a pitot tube blocks ram air pressure, causing the airspeed indicator to behave like an altimeter. Pitot heat keeps the tube clear so airspeed indications remain reliable.

Question 21Aircraft Fundamentals

A load factor of 3.0 during a maneuver means that the:

  1. Aircraft is climbing at three times its normal rate
  2. Airspeed is three times the normal value
  3. Stall speed is three times the normal value
  4. Structural load equals three times the aircraft's weight Correct answer.

Explanation

Load factor is the ratio of total lift to weight, so at 3.0 the structure carries three times the aircraft's weight. Stall speed increases by the square root of the load factor, not by the factor itself.

Question 22Aircraft Fundamentals

Before two AC generators are connected in parallel, they must be matched in:

  1. Phase and frequency Correct answer.
  2. Voltage and current
  3. Voltage and resistance
  4. Frequency and current

Explanation

AC sources can be paralleled only when their output voltages are in phase and at the same frequency. If they are not synchronized, large circulating currents will flow between the generators.

Question 23Aircraft Fundamentals

A hydraulic fluid sample is reported as NAS 1638 Class 6. This value describes the fluid's:

  1. Maximum allowable moisture content
  2. Viscosity at operating temperature
  3. Particle contamination level Correct answer.
  4. Resistance to foaming

Explanation

NAS 1638 defines cleanliness classes by counting particles in specified size ranges per 100 mL of sample. A higher class number means a greater number of contaminant particles.

Question 24Aircraft Fundamentals

Which design approach removes a component from service at a fixed number of cycles before a crack is expected to form?

  1. Safe-life design Correct answer.
  2. Damage-tolerant design
  3. Fail-safe design
  4. On-condition maintenance

Explanation

Safe-life components are given a finite life based on fatigue testing and analysis and are retired before cracks are predicted to initiate. Fail-safe and damage-tolerant designs instead rely on alternate load paths and inspection.

Question 25Aircraft Fundamentals

In a split-bus electrical system, the bus tie breaker allows the crew to:

  1. Block reverse current from the battery
  2. Limit current to each avionics unit
  3. Convert 115 V AC to 28 V DC
  4. Isolate a faulted source Correct answer.

Explanation

Bus tie breakers connect the main buses so either generator can supply both, and they open to isolate a faulted source or to separate the buses. This gives dispatch flexibility and fault isolation.

Question 26Aircraft Fundamentals

An airplane wing stalls when the:

  1. airspeed exceeds the never-exceed speed
  2. airplane climbs above its service ceiling
  3. flaps are extended beyond 20 degrees
  4. angle of attack exceeds the critical angle Correct answer.

Explanation

A wing stalls when the angle of attack exceeds the critical angle, at which point the airflow separates from the upper surface and lift drops sharply. This can happen at any airspeed, weight, or attitude, which is why angle of attack rather than speed defines the stall.

Question 27Aircraft Fundamentals

In semimonocoque construction, the primary flight loads are carried by the:

  1. the spar carry-through fittings exclusively
  2. a fabric envelope stretched over wooden ribs
  3. the stressed skin, stringers, and frames Correct answer.
  4. an internal truss of welded diagonal tubes

Explanation

Semimonocoque structure uses the skin itself as a load-carrying member, with stringers and frames stiffening it and distributing loads to the spars and bulkheads. Because the skin carries shear and tension, damage to it reduces the strength of the structure.

Question 28Aircraft Fundamentals

Which fastener is designed for installation where only one side of the structure can be reached?

  1. Hi-Lok pin and collar
  2. Hex-head bolt and nut
  3. Solid shank rivet
  4. Blind rivet Correct answer.

Explanation

Blind rivets are set from the accessible side only; the far end forms its own shop head against the structure. Solid shank rivets, bolts with nuts, and collar-type fasteners all require access to the back side for bucking or for installing the mating part.

Question 29Aircraft Fundamentals

Wing dihedral is incorporated primarily to improve:

  1. directional stability
  2. lateral stability Correct answer.
  3. longitudinal balance
  4. longitudinal stability

Explanation

With dihedral, a sideslip causes the lower wing to meet the airflow at a greater effective angle of attack than the upper wing, producing a rolling moment that tends to level the wings. This gives positive lateral (roll) stability.

Question 30Aircraft Fundamentals

An aircraft weighs 3,000 pounds with its center of gravity at 40 inches aft of the datum. A 200-pound item is loaded at a station 60 inches aft of the datum. The new center of gravity is:

  1. 41.25 inches Correct answer.
  2. 43.75 inches
  3. 40.50 inches
  4. 42.00 inches

Explanation

Total moment equals 3,000 times 40 plus 200 times 60, or 132,000 pound-inches, and total weight is 3,200 pounds. Dividing moment by weight gives 41.25 inches aft of the datum.

Question 31Aircraft Fundamentals

In the aluminum designation 2024-T6, the T6 indicates the metal has been:

  1. solution heat-treated and artificially aged Correct answer.
  2. strain-hardened by rolling at the rolling mill
  3. cold worked only, with no thermal treatment
  4. annealed to its softest possible condition

Explanation

The T temper prefix denotes a thermally treated alloy, and the 6 shows it was solution heat-treated and then artificially aged to develop strength. Temper designations matter because the same alloy in different tempers has very different strength and formability.

Question 32Aircraft Fundamentals

The standard flare angle for AN flared tubing fittings is:

  1. 30 degrees
  2. 37 degrees Correct answer.
  3. 60 degrees
  4. 45 degrees

Explanation

AN flare fittings use a 37-degree flare, which is the aircraft standard for rigid and flexible fluid lines. A 45-degree flare belongs to the automotive (AC) fitting family and will not seal properly against a 37-degree AN fitting.

Question 33Aircraft Fundamentals

A balance weight is installed ahead of the hinge line of an elevator primarily to:

  1. reduce the control forces felt by the pilot
  2. keep the surface from fluttering at high speed Correct answer.
  3. increase the maximum elevator deflection angle
  4. hold the surface neutral when the controls are released

Explanation

Placing mass ahead of the hinge line moves the surface's center of gravity to or ahead of the hinge, so inertial forces do not drive the surface to increasing deflection. Without that balance, the coupling of structural bending and control-surface motion can sustain flutter.

Question 34Aircraft Fundamentals

Two wings have equal area and are flown at the same speed and lift coefficient, but one has a higher aspect ratio. The higher-aspect-ratio wing will have:

  1. lower induced drag Correct answer.
  2. higher induced drag
  3. the same induced drag
  4. higher zero-lift drag

Explanation

Induced drag is proportional to the square of the lift coefficient divided by aspect ratio, so a longer, narrower wing produces less induced drag for the same lift. This is why sailplanes and long-range aircraft use high-aspect-ratio wings.

Question 35Basic Electricity and Electronics

A 12-ohm resistor carries a current of 0.5 A. What is the voltage across the resistor?

  1. 6 V Correct answer.
  2. 0.04 V
  3. 12 V
  4. 24 V

Explanation

Ohm's law states that voltage equals current multiplied by resistance, V = I x R. Substituting gives 0.5 A x 12 ohms = 6 V.

Question 36Basic Electricity and Electronics

A 220-ohm resistor and a 330-ohm resistor are connected in series. What is the total resistance of the combination?

  1. 550 ohms Correct answer.
  2. 132 ohms
  3. 130 ohms
  4. 275 ohms

Explanation

In a series circuit the same current flows through every component, so the resistances simply add. The total is 220 + 330 = 550 ohms.

Question 37Basic Electricity and Electronics

Two 100-ohm resistors are connected in parallel. What is the equivalent resistance of the pair?

  1. 100 ohms
  2. 25 ohms
  3. 200 ohms
  4. 50 ohms Correct answer.

Explanation

For two equal resistors in parallel, the equivalent resistance is half of one resistor's value because the product-over-sum rule reduces to R/2. Here 100 / 2 = 50 ohms.

Question 38Basic Electricity and Electronics

A circuit draws 2 A from a 12 V supply. How much power does the circuit dissipate?

  1. 6 W
  2. 0.17 W
  3. 48 W
  4. 24 W Correct answer.

Explanation

Electrical power in a DC circuit equals voltage multiplied by current, P = V x I. Multiplying 12 V by 2 A gives 24 W.

Question 39Basic Electricity and Electronics

A periodic AC signal completes one full cycle every 4 milliseconds. What is its frequency?

  1. 250 Hz Correct answer.
  2. 4 Hz
  3. 2.5 kHz
  4. 40 Hz

Explanation

Frequency is the reciprocal of the period, f = 1/T. With T = 0.004 s, f = 1 / 0.004 = 250 Hz.

Question 40Basic Electricity and Electronics

Four 1.5 V cells are connected in series. What is the total terminal voltage of the battery?

  1. 6 V Correct answer.
  2. 1.5 V
  3. 4.5 V
  4. 0.375 V

Explanation

Cells in series add their voltages while sharing the same current. Four cells at 1.5 V each give 4 x 1.5 = 6 V.

Question 41Basic Electricity and Electronics

What is the primary function of a diode in a circuit?

  1. Pass current in one direction Correct answer.
  2. Amplify the amplitude of a signal
  3. Store energy in an electric field
  4. Convert direct current to alternating current

Explanation

A diode is a PN junction that conducts readily when forward biased and blocks current when reverse biased. This one-way conduction is the basis of rectification and circuit protection.

Question 42Basic Electricity and Electronics

For a fixed wire material and temperature, the resistance of a conductor increases with which of the following?

  1. Increasing length Correct answer.
  2. Lower temperature
  3. Increasing cross-sectional area
  4. Decreasing length

Explanation

Resistance is directly proportional to length and inversely proportional to cross-sectional area. A longer wire forces current through more material, so resistance rises.

Question 43Basic Electricity and Electronics

At a circuit junction, 3 A of current enters and 1.2 A leaves through one branch. Assuming only one other branch leaves the junction, what current flows in that branch?

  1. 1.8 A Correct answer.
  2. 1.2 A
  3. 4.2 A
  4. 0.6 A

Explanation

Kirchhoff's current law states that current entering a junction equals current leaving it. The unknown branch therefore carries 3 A - 1.2 A = 1.8 A.

Question 44Basic Electricity and Electronics

A 12 V source is applied across a series combination of a 1 kilo-ohm and a 3 kilo-ohm resistor. What voltage appears across the 3 kilo-ohm resistor?

  1. 4 V
  2. 3 V
  3. 9 V Correct answer.
  4. 6 V

Explanation

In a series voltage divider, each resistor drops a share of the source voltage proportional to its resistance. The 3 kilo-ohm resistor is three-quarters of the 4 kilo-ohm total, so it drops 0.75 x 12 V = 9 V.

Question 45Basic Electricity and Electronics

Two 10 microfarad capacitors are connected in series. What is the total capacitance?

  1. 5 microfarads Correct answer.
  2. 10 microfarads
  3. 20 microfarads
  4. 2.5 microfarads

Explanation

Capacitors in series combine like resistors in parallel, so for two equal values the total is half of one value. The result is 5 microfarads.

Question 46Basic Electricity and Electronics

A 10 millihenry inductor is used in a circuit operating at 1 kHz. What is its inductive reactance?

  1. 6.28 ohms
  2. 15.9 ohms
  3. 628 ohms
  4. 62.8 ohms Correct answer.

Explanation

Inductive reactance is calculated as X_L = 2 pi f L. Using f = 1000 Hz and L = 0.01 H gives 2 x 3.1416 x 1000 x 0.01, which equals about 62.8 ohms.

Question 47Basic Electricity and Electronics

A sinusoidal voltage has a peak value of 170 V. What is its RMS value?

  1. 85 V
  2. 120 V Correct answer.
  3. 170 V
  4. 340 V

Explanation

For a sine wave, RMS voltage equals peak voltage divided by the square root of two. Dividing 170 V by 1.414 gives approximately 120 V.

Question 48Basic Electricity and Electronics

A transformer with 240 primary turns and 60 secondary turns is supplied with 120 V on the primary. What is the secondary voltage?

  1. 480 V
  2. 30 V Correct answer.
  3. 15 V
  4. 60 V

Explanation

The voltage ratio of a transformer equals the turns ratio, Vp/Vs = Np/Ns. Rearranging gives Vs = 120 V x (60 / 240) = 30 V.

Question 49Basic Electricity and Electronics

What is the decimal equivalent of the binary number 1011?

  1. 9
  2. 11 Correct answer.
  3. 13
  4. 7

Explanation

Each binary digit carries a weight of a power of two: 8, 4, 2, and 1. Adding the weights where a 1 appears gives 8 + 0 + 2 + 1 = 11.

Question 50Basic Electricity and Electronics

Which logic gate produces a HIGH output only when every input is HIGH?

  1. AND Correct answer.
  2. NAND
  3. XOR
  4. OR

Explanation

The AND function requires all inputs to be true before its output goes true. Any LOW input forces the AND output LOW.