FAA Aviation Maintenance Technician (AMT) Airframe Knowledge Test — Questions and Answers

Question 1: Which organization sets global aviation safety and security standards?

International Civil Aviation Organization (ICAO) (Correct answer)
National Aeronautics and Space Administration (NASA)
Airline Pilots Association (ALPA)
Federal Aviation Administration (FAA)

Correct answer: International Civil Aviation Organization (ICAO)

The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations that codifies the principles and techniques of international air navigation. ICAO sets global Standards and Recommended Practices (SARPs) for aviation safety, security, efficiency, and environmental protection. These standards are adopted by its member states to ensure a globally harmonized and safe air transport system.

Question 2: What is the correct procedure when mixing different brands of the same type of hydraulic fluid (e.g., Skydrol 500B-4 and Skydrol LD-4)?

Add a fluid conditioner before mixing
Drain, flush, and refill — different brands must not be mixed
Mixing is acceptable if both are phosphate ester type
Check with the aircraft manufacturer's CMM before mixing (Correct answer)

Correct answer: Check with the aircraft manufacturer's CMM before mixing

Even similar-type hydraulic fluids can have additive packages that interact adversely, so the aircraft manufacturer's Component Maintenance Manual must be consulted before mixing brands.

Question 3: An aircraft engine oil cooler bypass valve opens prematurely at low oil temperatures. The effect on the engine will be:

No effect since the thermostat regulates temperature independently
Oil that remains too cool, increasing viscosity and reducing lubrication effectiveness (Correct answer)
Excessively hot oil causing accelerated bearing wear
Lower oil pressure because of reduced pump load

Correct answer: Oil that remains too cool, increasing viscosity and reducing lubrication effectiveness

A bypass valve that opens prematurely routes cold oil around the cooler, keeping it too viscous, which reduces flow to bearings and impairs lubrication at low temperatures.

Question 4: An aircraft is returned for recurring nose-wheel shimmy. After replacing the shimmy damper with a serviceable unit, shimmy recurs immediately. The NEXT step is to inspect:

Nose gear fork bolt torque and wheel bearing preload (Correct answer)
Nose gear downlock mechanism for full engagement
Hydraulic system relief valve pressure setting
Main gear trunnion bearing for excessive play

Correct answer: Nose gear fork bolt torque and wheel bearing preload

Recurring shimmy after damper replacement indicates the root cause is mechanical looseness, most commonly excessive wheel bearing play or loose gear fork bolt torque.

Question 5: Which principle underpins Total Quality Management (TQM) in Aircraft Maintenance Certification?

Everyone in the organization is responsible for quality (Correct answer)
Top-down control only
Quality is only the QA department's job
Minimize customer feedback

Correct answer: Everyone in the organization is responsible for quality

TQM is based on the principle that quality is everyone's responsibility, from leadership to front-line workers.

Question 6: Which FAR part governs the airworthiness standards for aircraft electrical equipment?

FAR Part 23 (Correct answer)
FAR Part 21
FAR Part 65
FAR Part 91

Correct answer: FAR Part 23

FAR Part 23 establishes airworthiness standards for normal, utility, acrobatic, and commuter category airplanes, including electrical systems.

Question 7: What is the significance of the 'T6' temper designation for aluminum alloys such as 6061-T6?

Normalized after hot rolling
Solution heat-treated and artificially aged to peak strength (Correct answer)
Annealed to maximum softness
Cold-worked only, no heat treatment

Correct answer: Solution heat-treated and artificially aged to peak strength

T6 temper means the alloy was solution heat-treated then artificially aged (precipitation hardened), achieving near-maximum strength and hardness.

Question 8: Which skill is most important for success in Installation Techniques within Aircraft Maintenance Certification?

Working without any training
Continuous learning and adaptation (Correct answer)
Avoiding feedback
Resisting change

Correct answer: Continuous learning and adaptation

Continuous learning ensures professionals stay current with evolving practices in Installation Techniques.

Question 9: An aircraft static system check reveals the altimeter reads 50 feet higher than field elevation when on the ground with correct baro set. The MOST likely cause is:

Incorrect barometric setting by the pilot
A blocked or mislocated static port sensing higher-than-actual static pressure (Correct answer)
Altimeter vibration damage
Altimeter instrument error within limits

Correct answer: A blocked or mislocated static port sensing higher-than-actual static pressure

A static port in a high-pressure area (such as near an airflow disruption) reads higher pressure, which the altimeter interprets as lower altitude.

Question 10: During inspection of an aircraft fuel system, you discover a blue stain around a fuel cap gasket. This finding indicates:

Microbial growth in the fuel cell
Fuel contamination with hydraulic fluid
A fuel cap seal leak requiring gasket replacement (Correct answer)
Fuel dye residue from recent sumping — no action required

Correct answer: A fuel cap seal leak requiring gasket replacement

Blue staining (from aviation gasoline dye) around the fuel cap area is evidence of a leaking cap gasket that must be replaced.

Question 11: When must a mechanic holding an A&P certificate refuse to sign off maintenance?

When a manufacturer's service bulletin has not been incorporated
When the aircraft owner is not present
When the work is outside the mechanic's skill or knowledge for that specific task (Correct answer)
When the work was performed at a non-certificated facility

Correct answer: When the work is outside the mechanic's skill or knowledge for that specific task

14 CFR 65.81 prohibits a mechanic from exercising privileges for work they are not competent to perform, requiring refusal when beyond their skill.

Question 12: What causes hydraulic fluid to appear milky or foamy?

Metal particle contamination
Seal degradation only
Overheating only
Water contamination (Correct answer)

Correct answer: Water contamination

Water contamination causes hydraulic fluid to appear milky or foamy due to emulsification, which degrades lubrication and can cause corrosion and ice formation.

Question 13: Which document defines the approved avionics equipment for a specific aircraft?

FAR Part 91
Pilot Operating Handbook only
AC 43.13-1B
Aircraft Equipment List / AFMS (Correct answer)

Correct answer: Aircraft Equipment List / AFMS

The Aircraft Equipment List or Approved Flight Manual Supplement (AFMS) documents which avionics are approved for installation on a specific aircraft.

Question 14: When replacing an aircraft antenna coaxial cable, what must be verified after installation?

Cable color coding
Cable temperature rating only
Connector pin count
VSWR (Voltage Standing Wave Ratio) (Correct answer)

Correct answer: VSWR (Voltage Standing Wave Ratio)

VSWR must be measured after coaxial cable replacement to verify proper impedance matching and antenna system efficiency.

Question 15: A fuel-injected aircraft engine experiences a sudden loss of power at cruise altitude with fuel flow remaining normal. The MOST likely cause is:

Fuel control unit overspeed governor activation
Induction air duct collapse or obstruction downstream of the air filter (Correct answer)
Exhaust gas temperature probe failure
Alternate air door stuck in the closed position

Correct answer: Induction air duct collapse or obstruction downstream of the air filter

Normal fuel flow with sudden power loss suggests adequate fuel delivery but restricted airflow, most likely from an induction duct collapse or obstruction.

Question 16: Before performing maintenance on an aircraft hydraulic system, what is the first action a technician must take?

Depressurize the system and verify zero pressure (Correct answer)
Bleed the accumulator
Change the hydraulic filter
Top off the reservoir

Correct answer: Depressurize the system and verify zero pressure

The system must be fully depressurized and pressure verified at zero before opening any hydraulic line to prevent fluid injection injury or component ejection.

Question 17: An Airworthiness Directive (AD) requires a one-time inspection. The AD compliance is documented in the aircraft records and the inspection is complete. The mechanic's NEXT required action regarding this AD is:

Add the AD to the aircraft's recurring inspection checklist
No further action required — a one-time AD is complete after first compliance (Correct answer)
Re-inspect at the next annual inspection
File a copy of the AD with the FAA Flight Standards District Office

Correct answer: No further action required — a one-time AD is complete after first compliance

A one-time AD requires no further recurring action once the required inspection or repair is performed and documented.

Question 18: What is the purpose of a flux gate compass in an aircraft?

Regulate alternator field current
Sense fuel quantity
Detect the Earth's magnetic field for heading reference (Correct answer)
Measure static air pressure

Correct answer: Detect the Earth's magnetic field for heading reference

A flux gate compass uses electromagnetic induction to precisely sense the Earth's magnetic field, providing an accurate heading reference for remote indicating compasses and autopilots.

Question 19: A repair station certificated under 14 CFR Part 145 must display its certificate:

In the FAA regional office for that district
Only in the station's office files
On every aircraft it releases to service
At a location visible to customers at the repair station (Correct answer)

Correct answer: At a location visible to customers at the repair station

14 CFR 145.57 requires a repair station certificate to be displayed at a location visible to customers.

Question 20: What is the primary function of an aircraft engine oil system?

To lubricate engine components and dissipate heat (Correct answer)
To generate electrical power
To control flight surfaces
To provide fuel to the engine

Correct answer: To lubricate engine components and dissipate heat

The primary function of an aircraft engine oil system is to lubricate moving parts, reducing friction and wear, which is crucial for the engine's longevity and efficient operation. Additionally, the oil system plays a significant role in dissipating heat generated during combustion and friction, helping to maintain optimal engine operating temperatures.

Question 21: During ground testing, fuel is found in the engine oil. What is the MOST likely cause on a reciprocating engine?

Failed primer system or leaking fuel injection nozzle flooding the intake (Correct answer)
Carburetor float level too low
Overfilled fuel tanks
Fuel pump pressure too high

Correct answer: Failed primer system or leaking fuel injection nozzle flooding the intake

Fuel can enter the crankcase via a leaking primer or flooded injection nozzle, allowing raw fuel to pass the rings into the oil.

Question 22: A turboprop engine has a higher-than-normal torque reading for a given power lever position. What is the MOST likely explanation?

Fuel flow transducer failure
Compressor inlet blockage
Propeller pitch stuck in a lower blade angle than commanded (Correct answer)
Propeller governor overspeed

Correct answer: Propeller pitch stuck in a lower blade angle than commanded

Lower-than-commanded propeller blade angle increases drag on the propeller, causing the engine to develop more torque to maintain speed.

Question 23: When bonding aircraft components, what maximum resistance is typically allowed between bonded parts?

0.001 ohm
0.003 ohm
0.05 ohm (Correct answer)
1.0 ohm

Correct answer: 0.05 ohm

FAA Advisory Circulars specify that bonding connections should not exceed 0.003 ohm to ensure effective static discharge and EMI shielding.

Question 24: Which hand tool is specifically designed to cut external threads on a rod or bolt?

Tap
Thread chaser
Die (Correct answer)
Reamer

Correct answer: Die

A die is used to cut external threads on cylindrical stock, while a tap cuts internal threads inside a hole.

Question 25: What action is required when a mechanic discovers a defect that could endanger the aircraft but is outside the scope of their work order?

Ignore it and complete only the assigned task
Ground the aircraft and call the FAA
Notify the aircraft owner or operator of the unsafe condition (Correct answer)
Repair it immediately without notifying anyone

Correct answer: Notify the aircraft owner or operator of the unsafe condition

14 CFR 43.13 requires the mechanic to notify the owner or operator of any unsafe condition found during maintenance.

Question 26: Which skill is most important for success in Blueprint Reading & Interpretation within Aircraft Maintenance Certification?

Continuous learning and adaptation (Correct answer)
Avoiding feedback
Working without any training
Resisting change

Correct answer: Continuous learning and adaptation

Continuous learning ensures professionals stay current with evolving practices in Blueprint Reading & Interpretation.

Question 27: What fluid is specified for most Boeing commercial aircraft hydraulic systems?

Water-glycol
MIL-PRF-83282 (synthetic hydrocarbon)
Skydrol (phosphate ester) (Correct answer)
MIL-PRF-5606 (red mineral oil)

Correct answer: Skydrol (phosphate ester)

Boeing commercial aircraft use Skydrol, a fire-resistant phosphate ester hydraulic fluid, to reduce fire risk in the event of a hydraulic leak.

Question 28: What is the function of a borescope in aircraft maintenance?

To clean fuel lines
To detect radio signals
To inspect internal aircraft components without disassembly (Correct answer)
To measure airspeed

Correct answer: To inspect internal aircraft components without disassembly

A borescope is an optical instrument used in aircraft maintenance to visually inspect internal components of engines, airframes, and other systems without requiring extensive disassembly. This non-destructive inspection method saves significant time and cost while allowing technicians to identify potential issues like cracks, wear, or foreign object damage in hard-to-reach areas.

Question 29: When working in a confined space on an aircraft, what is the minimum requirement before entry?

A buddy system only
Wearing a hard hat and gloves
Atmospheric testing for oxygen, flammable, and toxic gases (Correct answer)
Notifying the crew chief verbally

Correct answer: Atmospheric testing for oxygen, flammable, and toxic gases

Confined space entry requires atmospheric testing to confirm oxygen levels (19.5–23.5%) and absence of hazardous gases before anyone enters.

Question 30: Which tool is commonly used for root cause analysis in Aircraft Maintenance Certification?

Fishbone (Ishikawa) diagram (Correct answer)
Organizational chart
Gantt chart
Profit and loss statement

Correct answer: Fishbone (Ishikawa) diagram

The fishbone diagram helps identify potential causes of a problem by organizing them into categories, revealing root causes.

Question 31: What is the function of an aircraft VOR receiver?

Measures distance to a ground station
Tracks GPS satellite signals
Receives weather data broadcasts
Provides magnetic bearing to/from a VOR station (Correct answer)

Correct answer: Provides magnetic bearing to/from a VOR station

A VOR receiver measures the phase difference between reference and variable signals to determine the aircraft's magnetic bearing to or from a VOR ground station.

Question 32: When inspecting a flight control cable for airworthiness, a technician finds 3 broken wires in one strand of a 7×19 cable. The correct disposition is:

Replace the cable; broken wire limits for 7×19 cable are typically exceeded with 3 broken wires in one strand (Correct answer)
The cable is serviceable; up to 6 broken wires per strand are allowed
Mark the location with safety wire and re-inspect at 25 hours
Splice the broken strand using an approved swaged fitting

Correct answer: Replace the cable; broken wire limits for 7×19 cable are typically exceeded with 3 broken wires in one strand

For 7×19 flight control cables, most manufacturer limits and AC 43.13 specify replacement when a defined number of broken wires are found in any given length, and 3 in one strand typically exceeds the limit.

Question 33: What is a primary function of an Aircraft Maintenance Program (AMP)?

To define the scheduled maintenance tasks and intervals required to maintain airworthiness (Correct answer)
To track aircraft fuel consumption
To authorize mechanics to perform inspections
To schedule pilot training intervals

Correct answer: To define the scheduled maintenance tasks and intervals required to maintain airworthiness

An AMP defines the required scheduled maintenance tasks, intervals, and inspection requirements to ensure continued airworthiness.

Question 34: What component prevents back-flow in a hydraulic line when downstream pressure exceeds upstream pressure?

Selector valve
Flow restrictor
Relief valve
Check valve (Correct answer)

Correct answer: Check valve

A check valve allows fluid flow in only one direction and closes automatically when downstream pressure exceeds upstream pressure, preventing back-flow.

Question 35: What is the foundation of professional ethics in Aircraft Maintenance Certification?

Maximizing profit at all costs
Following only verbal instructions
Avoiding difficult decisions
Acting with integrity, honesty, and accountability (Correct answer)

Correct answer: Acting with integrity, honesty, and accountability

Professional ethics are built on principles of integrity, honesty, and accountability, which guide practitioners in making responsible decisions.

Question 36: What condition does a hydraulic system ground test must verify before return to service after seal replacement?

Filter bypass indicator has not popped
No external leaks at operating pressure and correct actuator travel (Correct answer)
Accumulator pre-charge pressure only
Fluid color returns to original

Correct answer: No external leaks at operating pressure and correct actuator travel

A post-maintenance ground test must confirm no external leaks at full operating pressure and verify that all affected actuators move through their correct range of travel.

Question 37: A hydraulic pump that delivers a fixed volume of fluid per revolution regardless of system pressure is called:

Electric motor pump
Fixed-displacement (constant delivery) pump (Correct answer)
Demand pump
Variable-displacement pump

Correct answer: Fixed-displacement (constant delivery) pump

A fixed-displacement pump delivers the same volume per revolution regardless of system pressure; excess flow must be relieved or unloaded.

Question 38: A technician finds a cracked engine mount on a small GA aircraft during a 100-hour inspection. The engine mount is classified as a:

Minor repair item correctable using AC 43.13 standard practices
Principal Structural Element requiring FAA-approved repair data (Correct answer)
Cosmetic deficiency deferrable to the next annual inspection
Component requiring only a logbook entry before return to service

Correct answer: Principal Structural Element requiring FAA-approved repair data

Engine mounts are Principal Structural Elements (PSEs); any crack requires FAA-approved repair data and cannot be addressed with generic standard practices alone.

Question 39: What is the minimum wire bend radius typically specified to prevent conductor damage in aircraft wiring bundles?

5× wire diameter
10× wire diameter
1× wire diameter
3× wire diameter (Correct answer)

Correct answer: 3× wire diameter

AC 43.13-1B specifies that aircraft wire should not be bent to a radius less than 3 times the wire's outside diameter to avoid insulation cracking and conductor fatigue.

Question 40: When using a torque wrench, in which direction should you apply force relative to the wrench handle to get an accurate reading?

At 90 degrees to the handle
In-line with the handle from the pivot point (Correct answer)
At 45 degrees to the handle
Direction does not affect accuracy

Correct answer: In-line with the handle from the pivot point

Torque wrenches are calibrated for force applied in-line with the handle at the grip point; off-axis force produces inaccurate readings.

Question 41: After replacing a primary flight control cable, the mechanic must verify:

Cable routing using the aircraft's weight and balance data
Cable tension using a tensiometer and correct turnbuckle safety method (Correct answer)
Cable part number matches the airframe log only
That no more than three broken wires exist in any one-foot section

Correct answer: Cable tension using a tensiometer and correct turnbuckle safety method

Control cable tension must be measured with a tensiometer and turnbuckles must be safetied per approved methods after any cable replacement.

Question 42: What is the primary purpose of a current limiter in an aircraft electrical circuit?

Balance multiple bus bars
Regulate voltage output
Increase circuit ampacity
Protect wiring from overload (Correct answer)

Correct answer: Protect wiring from overload

A current limiter (fusible link) opens the circuit to protect wiring from damage caused by excessive current flow.

Question 43: When leak-checking a turbine engine fuel manifold after maintenance, the test medium specified by most manufacturers is:

Nitrogen gas at 1.5 times operating pressure (Correct answer)
Fuel at idle engine flow rate during a ground run
Compressed air at system operating pressure
Hydraulic test fluid at operating pressure

Correct answer: Nitrogen gas at 1.5 times operating pressure

Nitrogen is used for pressure leak checks because it is inert and non-flammable, and testing at 1.5 times operating pressure verifies a positive margin of safety.

Question 44: What is a fundamental principle of Material Selection & Properties in Aircraft Maintenance Certification practice?

Working in isolation without guidance
Following established standards and best practices (Correct answer)
Using outdated methods
Ignoring industry guidelines

Correct answer: Following established standards and best practices

Following established standards and best practices ensures quality and consistency in Material Selection & Properties.

Question 45: An airworthiness directive (AD) requires repetitive inspections at 100-hour intervals. The aircraft is currently at 2,347 hours. At what total time is the NEXT inspection due?

2,400 hours (Correct answer)
2,300 hours
2,447 hours
2,347 hours

Correct answer: 2,400 hours

Repetitive ADs are complied with at the next interval boundary; rounding up to the nearest 100-hour increment from 2,347 gives 2,400 hours.

Question 46: What is the purpose of a 'First Article Inspection' (FAI) in aircraft parts manufacturing?

To test the first completed aircraft in each production series for airworthiness
To inspect only the first part received in each shipment from a supplier
To audit the manufacturing facility before production begins
To verify that the first production unit completely conforms to design drawings and specifications (Correct answer)

Correct answer: To verify that the first production unit completely conforms to design drawings and specifications

A First Article Inspection (AS9102) validates that the initial production unit matches all engineering design requirements before serial production is authorized.

Question 47: What does a transponder Mode C provide to ATC?

Aircraft position and heading
Pressure altitude and identification (Correct answer)
Aircraft identification only
Ground speed and track

Correct answer: Pressure altitude and identification

Mode C transponders encode and transmit the aircraft's pressure altitude along with its squawk code to ATC radar.

Question 48: What is the maximum interval between inspections for an aircraft operated under a progressive inspection program?

100 hours
200 hours
12 calendar months
As specified in the approved program (Correct answer)

Correct answer: As specified in the approved program

Under a progressive inspection program, inspection intervals are set by the FAA-approved program itself, not a fixed regulatory limit.

Question 49: What does the term 'work hardening' (strain hardening) describe?

Hardening by rapid quenching from elevated temperature
Hardening by heat treatment above the critical temperature
Surface hardening by carbon diffusion
Increased hardness and strength resulting from plastic deformation at room temperature (Correct answer)

Correct answer: Increased hardness and strength resulting from plastic deformation at room temperature

Work hardening occurs when plastic deformation increases dislocation density, making further deformation more difficult and raising hardness and strength.

Question 50: What is the primary purpose of a pre-flight inspection in aircraft maintenance?

To increase fuel efficiency
To record passenger details
To verify airworthiness and safety before flight (Correct answer)
To clean the exterior of the aircraft

Correct answer: To verify airworthiness and safety before flight

The primary purpose of a pre-flight inspection in aircraft maintenance is to verify the airworthiness and safety of the aircraft before each flight. This critical procedure involves a thorough visual and functional check of key systems and components to ensure they are in proper working order, confirming the aircraft's readiness for safe operation.

Question 51: The purpose of a heat gun used in aircraft maintenance is best described as:

Providing controlled heat for tasks such as heat-shrink tubing installation and adhesive removal (Correct answer)
Drying aircraft wash water at temperatures above 400°F
Replacing an oxy-acetylene torch for welding thin sheet metal
Pre-heating hydraulic fluid before system bleeding

Correct answer: Providing controlled heat for tasks such as heat-shrink tubing installation and adhesive removal

Heat guns deliver regulated hot air for shrinking heat-shrink tubing, removing decals, softening adhesives, and similar low-temperature thermal tasks.

Question 52: A static inverter in an aircraft converts:

High voltage AC to low voltage AC
28V DC to 14V DC
DC to AC (Correct answer)
AC to DC

Correct answer: DC to AC

A static inverter converts DC power from the aircraft bus to AC power needed by instruments and avionics equipment.

Question 53: According to 14 CFR 43.13, maintenance must be performed using methods, techniques, and practices prescribed in:

The aircraft owner's personal logbook
The manufacturer's current maintenance manual or FAA-approved equivalent data (Correct answer)
The mechanic's own best judgment without reference documents
Any aviation textbook published after 1990

Correct answer: The manufacturer's current maintenance manual or FAA-approved equivalent data

14 CFR 43.13 requires mechanics to use the manufacturer's current maintenance manual or other FAA-approved data as the basis for all maintenance.

Question 54: What protection device should be used in an aircraft circuit rather than a fuse when repeated resetting may be required in flight?

Zener diode
Circuit breaker (Correct answer)
Current limiter
Thermal switch

Correct answer: Circuit breaker

Circuit breakers are preferred over fuses in circuits that may need to be reset in flight because they can be manually reset without replacement.

Question 55: Which of the following correctly describes a 'buddy system' as used in aviation maintenance safety?

A training requirement where a new hire shadows a licensed mechanic for 90 days
Two mechanics signing off the same logbook entry
Two technicians sharing the same task card to speed up work
One technician monitoring another during hazardous operations such as confined space entry or working at height (Correct answer)

Correct answer: One technician monitoring another during hazardous operations such as confined space entry or working at height

A buddy system pairs a working technician with an observer during high-risk tasks to provide immediate assistance or emergency response if an incident occurs.

Question 56: An engine fuel system shows erratic fuel flow indications. After verifying the fuel flow transmitter is serviceable, the technician should next inspect:

Fuel cap venting
Primer system check valves
Fuel tank sump for water
Fuel flow divider valve for sticking or contamination (Correct answer)

Correct answer: Fuel flow divider valve for sticking or contamination

A sticking or contaminated flow divider valve causes uneven fuel distribution and erratic fuel flow readings across the engine.

Question 57: A Standard Airworthiness Certificate becomes invalid when:

The annual inspection is overdue by 30 days
The aircraft is hangared for more than 90 days
The aircraft is not maintained in an airworthy condition (Correct answer)
The aircraft changes ownership

Correct answer: The aircraft is not maintained in an airworthy condition

A Standard Airworthiness Certificate remains valid as long as the aircraft is maintained in an airworthy condition per applicable regulations.

Question 58: What must be included in an aircraft maintenance record after a repair?

Details of the work, completion date, and technician's signature (Correct answer)
Only the name of the airline
Only the aircraft tail number
Only the type of repair performed

Correct answer: Details of the work, completion date, and technician's signature

After any repair or inspection, proper maintenance record-keeping requires that the entry in the aircraft's logbook or maintenance record clearly describes the work performed. This entry must also include the date of completion and the signature and certificate number of the authorized technician. This ensures accountability, traceability, and compliance with aviation regulations, confirming the aircraft's airworthiness.

Question 59: What is the importance of staying current with trends in Tools & Equipment Operation for Aircraft Maintenance Certification?

It ensures practices remain effective and relevant (Correct answer)
It is not necessary once certified
Trends do not affect professional practice
It is only required for new professionals

Correct answer: It ensures practices remain effective and relevant

Staying current with industry trends ensures that professional practices remain effective, relevant, and aligned with evolving standards.

Question 60: Which FAA document defines the airworthiness standards for transport category airplanes?

14 CFR Part 25 (Correct answer)
14 CFR Part 23
14 CFR Part 27
14 CFR Part 29

Correct answer: 14 CFR Part 25

14 CFR Part 25 establishes airworthiness standards specifically for transport category airplanes.

Question 61: An ammeter that reads on the discharge side of zero indicates the aircraft battery is:

Discharging to supply the bus (Correct answer)
Fully charged and at rest
Being charged by the alternator
Disconnected from the bus

Correct answer: Discharging to supply the bus

A negative (discharge) ammeter reading means the battery is supplying current to the bus because the alternator output is insufficient.

Question 62: Which regulatory reference establishes weight and balance requirements for certificated aircraft maintenance?

14 CFR Part 91 only
14 CFR Part 65
AC 43.13-1B only
14 CFR Part 43 and the aircraft's approved Type Certificate Data Sheet (TCDS) (Correct answer)

Correct answer: 14 CFR Part 43 and the aircraft's approved Type Certificate Data Sheet (TCDS)

14 CFR Part 43 governs maintenance requirements, and the aircraft's TCDS contains FAA-approved weight and balance limits and data specific to the aircraft type.

Question 63: What information is required when computing weight and balance for a flight?

Only the total gross weight
Aircraft serial number and date of manufacture only
Weight and location of all items including passengers, baggage, cargo, and fuel (Correct answer)
Only passenger weights and fuel load

Correct answer: Weight and location of all items including passengers, baggage, cargo, and fuel

A complete weight and balance calculation requires the weight and arm (location) of every item on board — passengers, baggage, cargo, and fuel — to accurately determine the loaded CG.

Question 64: What is the purpose of the chip detector in an aircraft turbine engine lubrication system?

Measure oil viscosity changes
Detect ferrous metallic particles indicating internal wear or failure (Correct answer)
Filter large debris before the oil pump
Monitor oil temperature at the sump

Correct answer: Detect ferrous metallic particles indicating internal wear or failure

Chip detectors use a magnetic plug to capture ferrous metal particles, providing early warning of internal component wear or imminent failure.

Question 65: What is the primary purpose of grounding an aircraft before refueling?

To protect avionics from power surges
To comply with FAA weight-and-balance requirements
To keep the aircraft stationary on the ramp
To equalize static charge between the aircraft and fuel vehicle, preventing spark ignition (Correct answer)

Correct answer: To equalize static charge between the aircraft and fuel vehicle, preventing spark ignition

Bonding and grounding dissipate static electricity accumulated during fueling, eliminating ignition sources near flammable vapors.

Question 66: What does a red 'X' in an aircraft logbook signify?

A discrepancy or inoperative item that has been deferred per MEL
An item requiring immediate attention that grounds the aircraft (Correct answer)
An outdated entry that has been superseded
A completed maintenance action

Correct answer: An item requiring immediate attention that grounds the aircraft

A red 'X' indicates a discrepancy that grounds the aircraft until it is corrected and signed off by an authorized mechanic.

Question 67: On an aircraft structural drawing, what does 'FS 247.5' designate?

Fastener Size 247.5 series
Frame Spacing of 247.5 millimeters
Fuselage Station 247.5 inches from the datum reference point (Correct answer)
Fuel System line 247.5

Correct answer: Fuselage Station 247.5 inches from the datum reference point

FS refers to Fuselage Station, a measurement in inches from the aircraft's forward datum to locate structural positions along the fuselage.

Question 68: Which noise level triggers the mandatory use of hearing protection under OSHA general industry standards?

75 dB(A) for any duration
90 dB(A) for less than 1 hour
85 dB(A) over an 8-hour TWA (Correct answer)
95 dB(A) peak impulse noise

Correct answer: 85 dB(A) over an 8-hour TWA

OSHA's Hearing Conservation Amendment requires hearing protection when the 8-hour time-weighted average (TWA) reaches or exceeds 85 dB(A).

Question 69: In aircraft blueprint reading, what does the term 'DATUM' refer to?

The maximum allowable weight of a component
The date the drawing was originally created
The required surface finish specification
A fixed reference plane or point from which measurements are taken (Correct answer)

Correct answer: A fixed reference plane or point from which measurements are taken

A datum is an exact theoretical reference plane, axis, or point established on a drawing from which all feature locations are measured.

Question 70: How is hydraulic fluid contamination level typically classified in aircraft maintenance?

By FAR Part 43 fluid specs
By NAS 1638 or ISO 4406 cleanliness codes (Correct answer)
By color and viscosity only
By MIL-SPEC gravity rating

Correct answer: By NAS 1638 or ISO 4406 cleanliness codes

NAS 1638 and ISO 4406 cleanliness codes classify hydraulic fluid contamination by counting particle sizes per unit volume using automated particle counters.

Question 71: What is the standard voltage for most general aviation aircraft DC electrical systems?

24 volts
48 volts
12 volts
28 volts (Correct answer)

Correct answer: 28 volts

Most general aviation aircraft use a 28-volt DC electrical system, which is the FAA and MIL-SPEC standard.

Question 72: Which approach best supports quality outcomes in Blueprint Reading & Interpretation for Aircraft Maintenance Certification?

Rushing through tasks
Relying solely on intuition
Avoiding quality checks
Systematic application of evidence-based methods (Correct answer)

Correct answer: Systematic application of evidence-based methods

Evidence-based methods provide a reliable foundation for achieving consistent, high-quality outcomes.

Question 73: What is the function of a hydraulic accumulator?

Cool hydraulic fluid
Measure system pressure
Filter contaminants from fluid
Store pressurized fluid and dampen pressure surges (Correct answer)

Correct answer: Store pressurized fluid and dampen pressure surges

A hydraulic accumulator stores pressurized fluid under a pre-charged gas pressure to supplement pump output during peak demands and dampen pressure spikes.

Question 74: Why must non-sparking tools be used when working inside or near aircraft fuel tanks?

Metal-on-metal sparks can ignite residual fuel vapors in the explosive range (1.3–7.6% for Jet-A) (Correct answer)
FAA requires non-sparking tools for all avionics work
Non-sparking tools are required for composite structures
They are lighter and reduce technician fatigue

Correct answer: Metal-on-metal sparks can ignite residual fuel vapors in the explosive range (1.3–7.6% for Jet-A)

Residual fuel vapors in tanks can form flammable mixtures; a single spark from standard steel tools can trigger an explosion, so non-sparking (brass, bronze, or beryllium copper) tools are mandatory.

Question 75: Which of the following is NOT required in a maintenance record entry per 14 CFR 43.9?

Signature and certificate number of the person approving the work
Description of the work performed
Total flight hours logged on the aircraft (Correct answer)
Date the work was completed

Correct answer: Total flight hours logged on the aircraft

14 CFR 43.9 requires description of work, date, name, certificate number, and kind of certificate; total aircraft flight hours is not a mandated element.

Question 76: Which document authorizes return-to-service after a major repair on a certificated aircraft?

FAA Form 8060-4
FAA Form 8710-1
FAA Form 8130-3
FAA Form 337 (Correct answer)

Correct answer: FAA Form 337

FAA Form 337 (Major Repair and Alteration) must be completed and submitted to the FAA for major repairs on certificated aircraft.

Question 77: What wire gauge system is used for aircraft electrical wire sizing?

SWG (Standard Wire Gauge)
AWG (American Wire Gauge) (Correct answer)
IEC 60228
Metric cross-section (mm²)

Correct answer: AWG (American Wire Gauge)

AWG (American Wire Gauge) is the standard system used for aircraft electrical wire sizing in the United States per FAA guidance.

Question 78: What is exfoliation corrosion and on which aircraft structure type is it most commonly found?

Layered delamination corrosion in high-strength aluminum extrusions and rolled products (Correct answer)
Uniform surface oxidation on titanium panels
Intergranular attack on magnesium castings
Deep pitting on steel fasteners

Correct answer: Layered delamination corrosion in high-strength aluminum extrusions and rolled products

Exfoliation corrosion progresses along grain boundaries parallel to the surface in wrought aluminum products, causing leaf-like delamination visible as blistering.

Question 79: What is the purpose of a Corrective Action Report (CAR) in an airline maintenance quality system?

To schedule routine maintenance intervals
To authorize mechanics to perform out-of-scope repairs
To record fuel uplifts between flights
To document the root cause of a deficiency and the actions taken to prevent recurrence (Correct answer)

Correct answer: To document the root cause of a deficiency and the actions taken to prevent recurrence

A CAR documents the root cause analysis of a quality finding and the preventive actions taken to avoid recurrence.

Question 80: Before working on an aircraft radar system, a technician must ensure the:

Radar is de-energized and capacitors discharged (Correct answer)
Radar is powered on for warm-up
Antenna is pointed skyward
Battery is fully charged

Correct answer: Radar is de-energized and capacitors discharged

Aircraft radar systems store lethal high-voltage charges in capacitors that must be discharged before maintenance to prevent electrocution.

Question 81: What is the primary purpose of a Receiving Inspection in an aircraft maintenance facility?

To calibrate incoming test equipment
To audit supplier quality management systems
To test completed assemblies before installation
To verify parts and materials meet specifications before use (Correct answer)

Correct answer: To verify parts and materials meet specifications before use

Receiving inspection ensures incoming parts, materials, and components conform to purchase order specifications before they enter the production or repair process.

Question 82: When bleeding a hydraulic system, why must air be completely removed?

Air increases fluid viscosity
Air is compressible and causes spongy, unpredictable actuator response (Correct answer)
Air causes fluid to overheat only
Air accelerates seal wear only

Correct answer: Air is compressible and causes spongy, unpredictable actuator response

Air is compressible unlike hydraulic fluid, so trapped air causes spongy, inconsistent actuator movement and can lead to unsafe control responses.

Question 83: Aircraft pneumatic systems typically use which gas as the working medium?

Hydrogen
Nitrogen or filtered, dried air (Correct answer)
Carbon dioxide
Oxygen

Correct answer: Nitrogen or filtered, dried air

Aircraft pneumatic systems use dry nitrogen or filtered, moisture-free air to prevent corrosion and ice formation in valves and actuators.

Question 84: If the computed CG falls outside the aft CG limit, what is the result?

Increased stability and reduced stall speed
No effect on flight characteristics
Increased fuel efficiency due to reduced drag
Reduced longitudinal stability, making recovery from a stall more difficult (Correct answer)

Correct answer: Reduced longitudinal stability, making recovery from a stall more difficult

An aft CG reduces longitudinal stability, decreases the effectiveness of elevator control, and makes it harder to recover from a stall.

Question 85: Which component converts AC generator output to DC for aircraft bus use?

Voltage regulator
Inverter
Transformer
Rectifier/TRU (Correct answer)

Correct answer: Rectifier/TRU

A Transformer Rectifier Unit (TRU) steps down AC voltage and converts it to DC for the aircraft's DC bus.

Question 86: An aircraft drawing calls out 'FINISH PER SPEC MIL-A-8625 TYPE II CLASS 1'. What process does this specify?

Anodizing treatment for aluminum (Correct answer)
Chromate conversion coating for aluminum
Primer application for composite structures
Cadmium plating for steel fasteners

Correct answer: Anodizing treatment for aluminum

MIL-A-8625 Type II Class 1 specifies sulfuric acid anodizing for aluminum alloys, providing corrosion protection and improved adhesion.

Question 87: What is 'basic empty weight' of an aircraft?

The weight of the airframe, engines, and all installed equipment, including unusable fuel and full operating fluids (Correct answer)
The weight with all optional equipment removed
The weight with full fuel and no passengers
The weight of the aircraft minus crew and baggage

Correct answer: The weight of the airframe, engines, and all installed equipment, including unusable fuel and full operating fluids

Basic empty weight includes the airframe, engines, all permanently installed equipment, unusable fuel, and full operating fluids such as oil and hydraulic fluid.

Question 88: What type of wire is required in aircraft electrical systems to prevent fire hazard in fuel tank areas?

Teflon-insulated wire (Correct answer)
Bare copper wire
PVC-insulated wire
Aluminum wire

Correct answer: Teflon-insulated wire

Teflon (PTFE)-insulated wire is required near fuel tanks because it is highly resistant to fuel, heat, and flame.

Question 89: Which class of fire extinguisher is appropriate for an electrical fire in an avionics bay?

Class D
Class A
Class C (Correct answer)
Class B

Correct answer: Class C

Class C extinguishers use non-conductive agents and are rated for fires involving energized electrical equipment.

Question 90: What is the typical operating pressure range for a large transport aircraft hydraulic system?

8,000–10,000 psi
500–1,000 psi
3,000–5,000 psi (Correct answer)
1,500–2,000 psi

Correct answer: 3,000–5,000 psi

Large transport aircraft hydraulic systems typically operate between 3,000 and 5,000 psi, with many modern aircraft using 5,000 psi systems for reduced weight.

Question 91: What is the purpose of a hydraulic fuse in an aircraft system?

Indicate low fluid level
Automatically shut off flow when excessive flow rate indicates a leak (Correct answer)
Regulate pump output pressure
Filter large particles from fluid

Correct answer: Automatically shut off flow when excessive flow rate indicates a leak

A hydraulic fuse senses an abnormally high flow rate (indicating a downstream rupture or leak) and closes automatically to isolate the failed section and conserve fluid.

Question 92: When must a safety observer be present during aircraft fuel cell entry?

Only when requested by the technician
Always—OSHA requires an attendant outside every permit-required confined space (Correct answer)
Only if the cell has not been purged of fuel vapors
Only for personnel under 6 months of experience

Correct answer: Always—OSHA requires an attendant outside every permit-required confined space

OSHA 29 CFR 1910.146 mandates an attendant stationed outside every permit-required confined space entry at all times to monitor entrants and summon rescue.

Question 93: What property is measured by the Rockwell hardness test?

Fatigue life under cyclic loading
Tensile strength at yield point
Resistance to plastic deformation under indentation (Correct answer)
Impact energy absorption

Correct answer: Resistance to plastic deformation under indentation

The Rockwell hardness test measures a material's resistance to permanent indentation under a specific load, indicating surface hardness.

Question 94: What is the purpose of a hydraulic system relief valve?

Separate fluid from air
Limit maximum system pressure to protect components (Correct answer)
Reduce flow to actuators
Control actuator speed

Correct answer: Limit maximum system pressure to protect components

A relief valve opens to return fluid to the reservoir when system pressure exceeds the set maximum, protecting pumps, actuators, and lines from over-pressurization.

Question 95: Which pneumatic system component removes moisture from compressed air before it enters the distribution system?

Pressure relief valve
Air dryer/moisture separator (Correct answer)
Check valve
Pressure regulator

Correct answer: Air dryer/moisture separator

An air dryer or moisture separator removes water vapor from compressed air to prevent corrosion, ice formation, and valve freezing in the pneumatic distribution system.

Question 96: When using a borescope to inspect turbine blades, cracks that run perpendicular to the blade span are known as:

Corrosion pits
Creep cracks
Fatigue cracks (transverse cracks) (Correct answer)
Fretting damage

Correct answer: Fatigue cracks (transverse cracks)

Transverse (cross-grain) cracks perpendicular to the blade span are classic fatigue cracks caused by cyclic thermal and mechanical stress.

Question 97: Which seal material is NOT compatible with Skydrol hydraulic fluid?

Teflon (PTFE)
Buna-N (nitrile) rubber (Correct answer)
Butyl rubber
Ethylene propylene (EPDM)

Correct answer: Buna-N (nitrile) rubber

Nitrile (Buna-N) seals swell and deteriorate rapidly when exposed to Skydrol phosphate ester fluid and must not be used in these systems.

Question 98: What is the primary advantage of a variable-displacement hydraulic pump over a fixed-displacement pump?

Lower initial cost
Higher pressure output capability
Simpler internal design
Reduces flow when pressure demand is met, saving power and reducing heat (Correct answer)

Correct answer: Reduces flow when pressure demand is met, saving power and reducing heat

Variable-displacement pumps reduce or eliminate output when system pressure is satisfied, saving engine power and reducing heat generation in the hydraulic fluid.

Question 99: An aircraft ELT must be tested in accordance with:

FAR 43.15 — during each annual inspection only
FAR 91.409 — annually with IFR equipment
FAR 91.207 — within first 5 minutes of each UTC hour, for no more than 3 audio sweeps (Correct answer)
FAR 91.207 — within first 5 minutes of each UTC hour

Correct answer: FAR 91.207 — within first 5 minutes of each UTC hour, for no more than 3 audio sweeps

FAR 91.207 permits ELT functional testing only within the first 5 minutes of each UTC hour, limited to 3 audible sweeps to avoid false alarm reports.

Question 100: What is the purpose of a bootstrap reservoir in an aircraft hydraulic system?

Pressurize the reservoir using system hydraulic pressure (Correct answer)
Separate air from hydraulic fluid
Filter return line fluid
Store emergency fluid supply at low pressure

Correct answer: Pressurize the reservoir using system hydraulic pressure

A bootstrap reservoir uses system hydraulic pressure applied to a piston to pressurize the reservoir, ensuring positive pump inlet pressure at altitude where atmospheric pressure is low.

FAA Aviation Maintenance Technician (AMT) Airframe Knowledge Test

The FAA AMT Airframe (AMA) knowledge test evaluates candidates on airframe structures, hydraulic and pneumatic systems, electrical and avionics systems, and maintenance inspection and documentation required to earn an FAA Aviation Mechanic certificate with Airframe rating.

Questions

35 min

Time Limit

70%

To Pass

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