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FAA A&P Mechanic practice questions

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Question 1General

What is the area of a circle that has a radius of 5 inches?

  1. 15.71 square inches
  2. 31.42 square inches
  3. 78.54 square inches Correct answer.
  4. 157.1 square inches

Explanation

Area of a circle equals pi times the radius squared, so 3.1416 x 5 x 5 = 78.54 square inches. The radius, not the diameter, is used in the formula.

Question 2General

Which of these quantities is a scalar?

  1. Mass Correct answer.
  2. Weight
  3. Acceleration
  4. Velocity

Explanation

A scalar is fully described by magnitude alone, and mass meets that definition. Velocity, weight, and acceleration all require a direction as well as a magnitude.

Question 3General

Which statement correctly describes current in a series circuit?

  1. It is zero in every component except the one with the lowest resistance.
  2. It is the same through every component. Correct answer.
  3. It divides among the components in proportion to their resistance.
  4. It is greatest in the component with the highest resistance.

Explanation

A series circuit provides only one path for electron flow, so the same current passes through each component. Voltage, not current, divides across series resistances.

Question 4General

A Class C fire involves which of the following?

  1. Combustible metals
  2. Flammable liquids
  3. Ordinary combustible materials
  4. Energized electrical equipment Correct answer.

Explanation

Fires involving energized electrical equipment are Class C, and the extinguishing agent must be nonconductive. Once power is removed, the fire is classified by the material that is burning.

Question 5General

In the aluminum alloy designation 2024, the major alloying element is

  1. Magnesium
  2. Silicon
  3. Copper Correct answer.
  4. Zinc

Explanation

The first digit of the four-digit wrought aluminum designation identifies the principal alloying element, and the 2xxx series is alloyed mainly with copper. Copper-bearing alloys are strong but require protection against corrosion.

Question 6General

In weight and balance work, the arm of an item is defined as

  1. The distance from the datum to the center of gravity of the item Correct answer.
  2. The distance between the forward and aft center of gravity limits
  3. The point at which the aircraft would balance if suspended
  4. The weight of the item multiplied by its distance from the datum

Explanation

An arm is a measured distance from the datum to the item's center of gravity, usually expressed in inches. Multiplying an arm by a weight produces a moment.

Question 7General

Compliance with an Airworthiness Directive is

  1. Mandatory, and the compliance must be recorded Correct answer.
  2. Advisory only when the aircraft is operated under Part 91
  3. Recommended but not required for private aircraft
  4. Optional for aircraft that are not flown for hire

Explanation

Airworthiness Directives are rules issued to correct unsafe conditions, and the affected aircraft cannot be legally flown until they are complied with. The action taken must be documented in the aircraft records.

Question 8General

The flare angle used on an AN flare-type fitting is

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

Explanation

AN flare fittings use a 37-degree flare, which mates with the corresponding cone on the fitting body. Using the wrong flare angle prevents proper sealing and can cause a leak or failure.

Question 9General

An aircraft burns 12 gallons of fuel per hour. How many gallons are needed for a flight of 3 hours 20 minutes with a 45-minute reserve?

  1. 44 gallons
  2. 49 gallons Correct answer.
  3. 52 gallons
  4. 58 gallons

Explanation

Total time is 3.333 hours plus 0.75 hour of reserve, or about 4.08 hours. Multiplying by 12 gallons per hour gives approximately 49 gallons.

Question 10General

A 24-volt circuit has a total resistance of 6 ohms. What current flows in the circuit?

  1. 4 amperes Correct answer.
  2. 0.25 ampere
  3. 18 amperes
  4. 144 amperes

Explanation

Ohm's law states that current equals voltage divided by resistance, so 24 divided by 6 equals 4 amperes. Voltage and resistance must be expressed in volts and ohms.

Question 11General

Two 12-volt, 25-ampere-hour batteries are connected in parallel. The resulting combination provides

  1. 12 volts and 50 ampere-hours Correct answer.
  2. 24 volts and 50 ampere-hours
  3. 12 volts and 25 ampere-hours
  4. 24 volts and 25 ampere-hours

Explanation

In a parallel connection the positive terminals are joined together and the negative terminals are joined together, so the voltage stays the same while the capacity adds. Two 25-ampere-hour batteries therefore give 50 ampere-hours at 12 volts.

Question 12General

A drawing is marked SCALE 1/2. A line on the drawing measures 4.0 inches. What is the actual length of the part?

  1. 1.0 inch
  2. 0.5 inch
  3. 2.0 inches
  4. 8.0 inches Correct answer.

Explanation

A scale of 1/2 means the drawing is half the size of the actual part, so each drawn inch represents two actual inches. Multiplying 4.0 inches by 2 gives 8.0 inches.

Question 13General

In the designation 2024-T3, the T3 indicates that the alloy has been

  1. Annealed to its softest condition
  2. Cold-worked only, without any heat treatment
  3. Solution heat-treated and then cold-worked Correct answer.
  4. Hot-rolled and stress-relieved

Explanation

The T temper designations indicate thermal treatment, and T3 specifically means solution heat-treated, cold-worked to improve strength, and naturally aged. Material in this temper is stronger than the annealed O condition.

Question 14General

Which situation is most likely to promote galvanic corrosion?

  1. An aluminum sheet washed regularly with clean water
  2. Two identical aluminum alloy plates riveted together in a dry hangar
  3. A painted steel panel exposed to dry desert air
  4. A magnesium casting bolted to a steel bracket in a damp area Correct answer.

Explanation

Galvanic corrosion requires two dissimilar metals in contact plus an electrolyte, and dampness provides that electrolyte. Metals far apart on the galvanic scale, such as magnesium and steel, corrode most rapidly.

Question 15General

FAA Form 337 is used to

  1. Record a major repair or major alteration Correct answer.
  2. Apply for a special flight permit
  3. Report an aircraft accident to the NTSB
  4. Record the annual inspection of an aircraft

Explanation

Form 337 documents major repairs and major alterations along with the approved data used and the approving authority. It becomes part of the aircraft's permanent records.

Question 16General

Under FAA rules, a private pilot may perform preventive maintenance on an aircraft that the pilot

  1. Only at a certificated repair station using approved data
  2. Only if the aircraft is operated for compensation or hire
  3. Owns and operates, provided it is not operated for hire Correct answer.
  4. Only under the direct supervision of a certificated A&P mechanic

Explanation

A pilot certificated to at least the private level may perform preventive maintenance on an aircraft the pilot owns and operates, as long as it is not operated for compensation or hire. The work must be recorded in the maintenance records.

Question 17General

Before opening the filler cap on an aircraft during refueling, the recommended practice is to

  1. Ground the fuel truck to the ramp only
  2. Close all of the aircraft circuit breakers
  3. Remove the static wicks from the wing tips
  4. Bond the aircraft to the fuel source Correct answer.

Explanation

Bonding the aircraft to the fuel truck equalizes static potential between the two before fuel transfer begins. A difference in potential can produce a spark and ignite fuel vapor.

Question 18General

An aircraft has an empty weight of 1,200 pounds with a center of gravity at arm 40. A 200-pound item is added at arm 30. What is the new center of gravity location?

  1. 40.0 inches
  2. 37.5 inches
  3. 39.2 inches
  4. 38.6 inches Correct answer.

Explanation

Total moment is (1,200 x 40) plus (200 x 30), or 48,000 plus 6,000, giving 54,000 pound-inches. Dividing by the new total weight of 1,400 pounds gives about 38.6 inches.

Question 19General

Stress in a structural member is defined as

  1. The deformation produced by an applied load
  2. The internal force per unit of cross-sectional area Correct answer.
  3. The total load carried by the member
  4. The tendency of a load to twist the member

Explanation

Stress is the internal resistance expressed as force divided by the area over which it acts, commonly in pounds per square inch. It is distinct from strain, which is the resulting deformation.

Question 20General

Which procedure is acceptable for removing light surface corrosion from an aluminum alloy part?

  1. Scrub the area with steel wool until bare metal is exposed
  2. Apply household bleach to dissolve the corrosion products
  3. Sand the area with coarse grit paper until the pits disappear
  4. Rub the area with aluminum wool and apply a protective coating Correct answer.

Explanation

Aluminum wool or a nonmetallic abrasive removes corrosion without embedding foreign metal particles in the surface. The cleaned area must then be protected with an appropriate coating to prevent recurrence.

Question 21General

An aircraft has an empty weight of 1,500 pounds with a center of gravity at arm 38. Cargo will be loaded at arm 60, and the aft center of gravity limit is arm 40. What is the maximum cargo weight that can be carried?

  1. 125 pounds
  2. 150 pounds Correct answer.
  3. 175 pounds
  4. 100 pounds

Explanation

At the limit, the total moment divided by total weight equals 40: (57,000 + 60W) divided by (1,500 + W) = 40. Solving gives 20W = 3,000, so W equals 150 pounds.

Question 22General

Layers of metal lifting and flaking in sheets roughly parallel to the surface, often seen on extruded aluminum parts, indicate

  1. Pitting corrosion
  2. Exfoliation corrosion Correct answer.
  3. Galvanic corrosion
  4. Stress-corrosion cracking

Explanation

Exfoliation is intergranular corrosion that follows the grain boundaries of heavily worked metal, forcing thin layers apart. Extruded and rolled sections with directional grain structure are especially susceptible.

Question 23General

A dimension on an aircraft drawing is given as 3.250 plus or minus 0.010. Which measurement of the part is acceptable?

  1. 3.255 inches Correct answer.
  2. 3.262 inches
  3. 3.272 inches
  4. 3.238 inches

Explanation

The tolerance permits any dimension from 3.240 to 3.260 inches inclusive. Only 3.255 falls inside that range.

Question 24General

Under Part 91, maintenance records for work performed on an aircraft must be retained

  1. Until the aircraft is sold to another owner
  2. For 6 months after the work is performed
  3. For 2 years after the work is performed
  4. For 1 year after the work is performed or until the work is superseded Correct answer.

Explanation

The regulation requires retention of maintenance, preventive maintenance, and alteration records for at least one year after the work is done, or until the work is repeated or superseded. Records for certain items, such as life-limited parts, must be kept longer.

Question 25General

Aircraft alternating current systems commonly operate at 400 Hz rather than 60 Hz because the higher frequency

  1. Permits smaller and lighter transformers, motors, and generators Correct answer.
  2. Allows aluminum conductors to replace copper conductors
  3. Eliminates the need for a constant-speed drive
  4. Reduces the voltage required for a given amount of power

Explanation

Magnetic devices can be built smaller for a given power level as frequency increases, which saves weight on aircraft. The higher frequency is produced by a constant-speed drive or an inverter because the weight saving is worth the added complexity.

Question 26General

The unit of electrical power in the SI system is the

  1. volt
  2. ohm
  3. watt Correct answer.
  4. ampere

Explanation

Electrical power is the rate at which electrical energy is transferred and is measured in watts. One watt equals one joule per second, or one volt times one ampere.

Question 27General

The grip length of an aircraft bolt is measured from the underside of the head to the

  1. end of the threads
  2. center of the shank
  3. start of the threads Correct answer.
  4. top of the head

Explanation

Grip length covers the unthreaded shank portion that passes through the parts being joined. It is measured from the bearing surface under the head to the first thread.

Question 28General

Which extinguishing agent is appropriate for a fire involving magnesium?

  1. carbon dioxide from a CO2 extinguisher
  2. Class D dry powder Correct answer.
  3. water spray from a pressurized can
  4. aqueous foam solution

Explanation

Magnesium is a combustible metal, and combustible metal fires require a Class D extinguishing agent. Water and ordinary foam can react violently with burning magnesium. Carbon dioxide is not effective for deep-seated metal fires.

Question 29General

A torque wrench is used to

  1. measure twisting force applied to a fastener Correct answer.
  2. check the hardness of the fastener threads
  3. measure the stretch of the bolt shank directly
  4. measure the pitch of the fastener threads

Explanation

A torque wrench controls the amount of turning effort applied to a fastener. It indicates torque, which is force multiplied by lever arm, rather than bolt stretch or thread dimensions.

Question 30General

MIL-PRF-5606 mineral-base hydraulic fluid is normally colored

  1. red Correct answer.
  2. blue
  3. green
  4. clear

Explanation

MIL-PRF-5606 hydraulic fluid is dyed red to help identify it and distinguish it from other fluids. Color coding assists in preventing the wrong fluid from being added to a system.

Question 31General

Nitrogen is often used to inflate aircraft tires because it

  1. reduces fire hazard and moisture in the tire Correct answer.
  2. makes the tire assembly noticeably lighter
  3. increases the tire pressure automatically as it warms
  4. eliminates the need for any future pressure check

Explanation

Nitrogen is dry and does not support combustion, so it reduces the risk of a tire fire and minimizes moisture inside the wheel assembly. It does not eliminate the need for routine pressure checks.

Question 32General

The most common cause of corrosion on aircraft structures is

  1. vibration
  2. heat
  3. fuel
  4. moisture Correct answer.

Explanation

Moisture, often combined with salt or other contaminants, is the primary environmental factor that promotes corrosion. Corrosion control therefore focuses on preventing water accumulation and maintaining protective coatings.

Question 33General

An adjustable torque wrench should be stored

  1. at its lowest setting Correct answer.
  2. at any setting
  3. at its mid-range setting
  4. at its maximum setting

Explanation

Storing an adjustable torque wrench at its lowest setting relieves spring tension and helps preserve calibration. A wrench left compressed can take a set and lose accuracy.

Question 34General

A micrometer sleeve reads 0.200 inch and the thimble is on the 18th division. If the thimble has 25 divisions and one revolution advances 0.025 inch, the reading is

  1. 0.238 in
  2. 0.380 in
  3. 0.218 in Correct answer.
  4. 0.200 in

Explanation

Each thimble division represents 0.025 inch divided by 25, or 0.001 inch. Adding 18 divisions to the sleeve reading gives 0.200 + 0.018 = 0.218 inch.

Question 35General

A torque wrench is fitted with a crow's foot extension in line with the handle. To apply the specified torque at the fastener, the wrench setting should be

  1. converted to inch-pounds only
  2. decreased Correct answer.
  3. left unchanged
  4. increased

Explanation

An in-line extension increases the effective lever arm, so the wrench would otherwise apply more torque at the fastener than it indicates. The wrench setting must therefore be reduced according to the adapter formula.

Question 36General

In a series circuit containing three resistors, the current

  1. is divided among the resistors in proportion to resistance
  2. is the same at every point in the circuit Correct answer.
  3. equals the sum of all the voltage drops around the circuit
  4. is greatest across the largest resistor in the circuit

Explanation

A series circuit has only one path for current, so the same current flows through every component. The voltage drops divide in proportion to resistance.

Question 37General

A 12-volt battery is connected across a 3-ohm resistor. What power is dissipated by the resistor?

  1. 36 W
  2. 48 W Correct answer.
  3. 12 W
  4. 4 W

Explanation

Power can be found from P = V squared divided by R. Substituting gives 144 divided by 3, or 48 watts.

Question 38General

The empty weight and empty-weight center of gravity for a specific aircraft are normally recorded in the

  1. pilot's operating handbook limitations section
  2. type certificate data sheet only
  3. FAA registration certificate
  4. aircraft weight and balance report Correct answer.

Explanation

The weight and balance report documents the actual as-weighed empty weight and empty-weight center of gravity for that individual aircraft. It also records the arm and moment of each installed item.

Question 39General

The primary purpose of electrical bonding in an aircraft is to

  1. provide a low-resistance path for static and fault current Correct answer.
  2. reduce the overall weight of the electrical system
  3. allow aluminum wire to be used in place of copper wire
  4. increase the structural strength of the airframe assembly

Explanation

Bonding connects conductive structures so that static charges and fault currents have a low-resistance path. This helps protect against sparks, lightning damage, and electrical shock hazards.

Question 40General

When safety wiring two adjacent bolts, the wire should be installed so that

  1. the wire is twisted only at the ends of the run
  2. loosening pulls the wire toward tightening Correct answer.
  3. the wire is left loose so that it can flex with vibration
  4. the wire passes over the head of each bolt without tension

Explanation

Safety wire is routed so that any tendency of a fastener to loosen applies tension in the tightening direction. This keeps the wire taut and opposes rotation.

Question 41General

The datum used for aircraft weight and balance calculations is

  1. the forward limit of the center of gravity range
  2. an arbitrary manufacturer-selected reference point Correct answer.
  3. the main landing gear axle centerline
  4. the center of gravity of the empty aircraft

Explanation

The datum is an arbitrary reference point chosen by the manufacturer from which arms are measured. It may be located ahead of, behind, or within the aircraft.

Question 42General

A maintenance record entry for a major repair must include at least the

  1. aircraft total time and the shop name
  2. parts cost and the customer's signed receipt
  3. description, date, signature, and certificate number Correct answer.
  4. total labor hours and the date work started

Explanation

Maintenance records must describe the work performed, the date, and identify the person approving the work. For certified mechanics, the signature and certificate number provide that identification.

Question 43General

Major repairs and major alterations are defined in

  1. Part 39
  2. Part 43, Appendix A Correct answer.
  3. Part 65, Appendix B
  4. Part 91, Appendix D

Explanation

14 CFR Part 43, Appendix A, lists the work considered a major repair or major alteration. This classification affects what records and approvals are required.

Question 44General

The inside diameter of an engine cylinder bore is best measured with an

  1. inside micrometer or bore gauge Correct answer.
  2. vernier caliper
  3. feeler gauge
  4. outside micrometer

Explanation

An inside micrometer or a bore gauge is designed to measure internal diameters accurately. A telescoping gauge used with an outside micrometer is another acceptable method.

Question 45General

Aircraft fabric dope is applied primarily to

  1. provide color only and not affect the fabric
  2. shrink the fabric taut and form a base for finish Correct answer.
  3. clean the fabric and remove all old dope
  4. waterproof the fabric without affecting tautness

Explanation

Dope shrinks as it dries, tightening the fabric over the structure. It also builds a base to which subsequent coats and finishes can adhere.

Question 46General

Eddy current inspection is most useful for detecting

  1. magnetic flux leakage in ferromagnetic parts
  2. corrosion products trapped under paint
  3. surface and near-surface defects in conductive metals Correct answer.
  4. internal voids deep inside thick castings

Explanation

Eddy currents are induced in conductive materials and are disturbed by discontinuities near the surface. The method is therefore suited to cracks and similar flaws in conductive metals.

Question 47General

When 2024-T4 aluminum alloy is cold worked beyond its yield point, the material

  1. loses all resistance to corrosion
  2. returns to the annealed condition
  3. becomes softer and more ductile
  4. increases in strength and decreases in ductility Correct answer.

Explanation

Cold working strains the crystal structure and increases dislocation density, which raises strength. The same deformation reduces the amount of elongation the material can sustain before fracture.

Question 48General

An alternator must produce 400 Hz when driven at 6,000 rpm. How many poles does it need?

  1. 12 poles
  2. 8 poles Correct answer.
  3. 10 poles
  4. 6 poles

Explanation

Frequency equals poles times rpm divided by 120. Rearranging gives poles = 120 times frequency divided by rpm, so 120 times 400 divided by 6,000 equals 8 poles.

Question 49General

A 12-volt, 24-ampere-hour battery supplies a 48-watt load. Ignoring losses, how long can it supply the load?

  1. 3 hours
  2. 6 hours Correct answer.
  3. 5 hours
  4. 2 hours

Explanation

The load current is 48 watts divided by 12 volts, or 4 amperes. Dividing the 24-ampere-hour capacity by 4 amperes gives 6 hours.

Question 50General

In a sheet metal bend, the neutral axis is the location where the metal is

  1. at the neutral axis Correct answer.
  2. at the inner surface of the bend
  3. at the outer surface of the bend
  4. at the edge of the sheet

Explanation

The neutral axis lies within the bend where the material is neither stretched nor compressed. Material outside this axis is in tension, while material inside is in compression.