FAA Aviation Mechanic – ACS Airman Certification Standards Knowledge Test — Questions and Answers

Question 1: Aramid (Kevlar) fiber composite panels present a unique machining challenge because:

Aramid fibers are tough and tend to fray or delaminate rather than cut cleanly (Correct answer)
Aramid fibers conduct electricity, requiring insulated tooling
Aramid fibers expand significantly when heated by cutting tools
Aramid fibers are brittle and shatter when drilled

Correct answer: Aramid fibers are tough and tend to fray or delaminate rather than cut cleanly

Aramid fibers are extremely tough and absorb energy rather than fracturing, causing fuzzing and delamination during drilling or trimming without special tooling.

Question 2: When performing a bonding check on an aircraft, what maximum resistance is typically acceptable between two airframe components?

0.003 ohm (Correct answer)
0.1 ohm
1.0 ohm
10 ohms

Correct answer: 0.003 ohm

FAA AC 43.13-1B specifies that bonding connections should have resistance not exceeding 0.003 ohm (3 milliohms) for effective static discharge and EMI protection.

Question 3: After engine overhaul, a break-in run is performed. What oil type should NOT be used during engine break-in?

Ashless dispersant oil
Straight mineral oil
Multi-viscosity mineral oil
Synthetic oil (Correct answer)

Correct answer: Synthetic oil

Synthetic oil is too slippery during break-in and prevents cylinder walls from seating properly; mineral oil is required for new or overhauled engines.

Question 4: AC 43.13-1B is best described as:

A mandatory training curriculum for A&P schools
A legally binding regulation for all aircraft maintenance
The type certificate data sheet reference manual
FAA-accepted methods, techniques, and practices for aircraft inspection and repair (Correct answer)

Correct answer: FAA-accepted methods, techniques, and practices for aircraft inspection and repair

AC 43.13-1B provides FAA-accepted (not mandatory) methods, techniques, and practices for aircraft inspection and repair, commonly used when no manufacturer data exists.

Question 5: During a ground run, manifold pressure is 2 inches Hg higher than standard atmosphere with the throttle closed. What does this indicate?

Intake air filter is clogged
Supercharger is engaged
Throttle plate is not fully closing (Correct answer)
Manifold pressure gauge is miscalibrated

Correct answer: Throttle plate is not fully closing

A throttle plate that does not fully close allows high-pressure air to leak into the intake manifold, raising manifold pressure above atmospheric.

Question 6: Honeycomb core damage repair typically requires restoring core density primarily to:

Provide an attachment point for skin repair plies
Restore the electrical conductivity of the panel
Prevent moisture ingress into the honeycomb cells
Maintain the compressive and shear strength the core provides to the sandwich panel (Correct answer)

Correct answer: Maintain the compressive and shear strength the core provides to the sandwich panel

Honeycomb core transfers shear loads between face sheets and provides compressive stability; restoring equivalent density/cell size is essential for structural integrity.

Question 7: When using a Structural Repair Manual (SRM) for composite repairs, a mechanic must ensure the manual revision used is:

The latest revision that is current and applicable to the specific aircraft serial number (Correct answer)
Any revision published after the aircraft was manufactured
The revision the operator's maintenance director approves
The original issue regardless of subsequent revisions

Correct answer: The latest revision that is current and applicable to the specific aircraft serial number

Technicians must use the current, applicable revision of the SRM for the specific aircraft's serial number to ensure the repair meets the type design requirements.

Question 8: Which NDT method is most effective for detecting surface and near-surface cracks in ferromagnetic aircraft components?

Magnetic particle inspection (Correct answer)
Ultrasonic testing
Dye penetrant inspection
Eddy current testing

Correct answer: Magnetic particle inspection

Magnetic particle inspection (MPI) is specifically designed for ferromagnetic materials and can reveal both surface and subsurface discontinuities by applying a magnetic field and iron particles.

Question 9: What is the purpose of a magnetic particle inspection on steel aircraft components?

To check material hardness and tensile strength
To verify material composition and alloy type
To identify corrosion beneath paint coatings
To detect surface and near-surface cracks in ferromagnetic materials (Correct answer)

Correct answer: To detect surface and near-surface cracks in ferromagnetic materials

Magnetic particle inspection reveals surface and near-surface discontinuities in ferromagnetic materials by attracting iron particles to areas where magnetic flux leaks at defects.

Question 10: What is the primary radiation safety concern for technicians performing X-ray radiographic inspection?

Chemical burns from radiographic film developer solutions
Cumulative exposure to ionizing radiation increasing the risk of biological harm (Correct answer)
Ultraviolet skin burns from the X-ray tube housing
Hearing damage from high-frequency radiation noise

Correct answer: Cumulative exposure to ionizing radiation increasing the risk of biological harm

Ionizing radiation (X-rays and gamma rays) can damage living tissue and DNA; cumulative occupational exposure is regulated by the NRC/OSHA, and technicians must use dosimetry badges and stay within annual dose limits.

Question 11: What continuing education is typically required in weight & balance?

Regular training to stay current with industry standards, regulations, and best practices (Correct answer)
Only education obtained before certification matters
No continuing education is ever required
Training is only needed in the first year of certification

Correct answer: Regular training to stay current with industry standards, regulations, and best practices

Professional fields require ongoing education to ensure practitioners stay current with evolving standards, technologies, regulations, and best practices in their specialty.

Question 12: What does a sudden drop in fuel flow during an engine operational test with no corresponding change in throttle position indicate?

Mixture control moved inadvertently
Fuel vapor lock or cavitation in the fuel system (Correct answer)
Fuel pump pressure exceeding regulator limits
Idle cutoff valve partially engaging

Correct answer: Fuel vapor lock or cavitation in the fuel system

Vapor lock causes intermittent fuel starvation as fuel vaporizes in the fuel lines, creating a pocket that temporarily reduces liquid fuel flow.

Question 13: What is the purpose of a hydraulic system case drain line on a variable displacement piston pump?

Return low-pressure fluid that bypasses the internal piston seals back to the reservoir (Correct answer)
Carry pump output to a secondary system during low-demand periods
Supply lubrication fluid to the pump shaft bearing from an external source
Vent pressure from the pump housing if the outlet check valve fails

Correct answer: Return low-pressure fluid that bypasses the internal piston seals back to the reservoir

Case drain lines return internal leakage fluid that bypasses piston seals back to the reservoir, preventing case pressure buildup that could damage pump shaft seals.

Question 14: A reciprocating engine exhibits detonation during high-power operation. Which of the following will most effectively reduce detonation?

Enriching the fuel-air mixture (Correct answer)
Reducing cooling airflow
Advancing ignition timing
Leaning the mixture further

Correct answer: Enriching the fuel-air mixture

Enriching the mixture reduces cylinder temperatures and lowers the tendency for detonation by decreasing peak combustion temperatures.

Question 15: What document certifies an aircraft is airworthy?

Airworthiness Certificate (Correct answer)
Insurance Certificate
Operating Handbook
Registration Certificate

Correct answer: Airworthiness Certificate

The Airworthiness Certificate indicates an aircraft meets its approved design and is in a condition for safe operation.

Question 16: An aircraft's ELT activates inadvertently on the ground. What is the required action?

Allow it to transmit for no more than 10 minutes, then deactivate
Deactivate it immediately and report the inadvertent activation to the nearest FAA FSDO
Replace the ELT before the next flight regardless of the reason for activation
Notify ATC immediately and deactivate the ELT as quickly as possible (Correct answer)

Correct answer: Notify ATC immediately and deactivate the ELT as quickly as possible

An inadvertent ELT activation must be silenced immediately, and ATC must be notified to prevent unnecessary search and rescue operations.

Question 17: What is the main purpose of a pressurization system in an aircraft?

Vent fuel tanks
Prevent corrosion
Provide fresh air
Maintain cabin pressure (Correct answer)

Correct answer: Maintain cabin pressure

Pressurization systems maintain safe cabin pressure at high altitudes.

Question 18: What is the purpose of antiskid system on aircraft brakes?

To equalize brake pressure between left and right brakes
To prevent wheel lockup during braking, optimizing stopping distance and directional control (Correct answer)
To automatically apply brakes on landing touchdown
To reduce brake pedal effort for the pilot

Correct answer: To prevent wheel lockup during braking, optimizing stopping distance and directional control

The antiskid system monitors wheel speed and modulates hydraulic pressure to prevent lockup, maximizing braking efficiency and maintaining steering control.

Question 19: What is the purpose of the Minimum Equipment List (MEL) in aviation maintenance?

To list all tools required for a 100-hour inspection
To identify equipment that may be inoperative while still allowing safe flight under specific conditions (Correct answer)
To define the minimum qualifications for mechanics working on turbine aircraft
To outline required spare parts inventory for Part 145 stations

Correct answer: To identify equipment that may be inoperative while still allowing safe flight under specific conditions

An MEL specifies which systems or instruments may be inoperative with conditions and limitations, allowing dispatch of an aircraft that is not fully operational.

Question 20: If an aircraft hydraulic system uses MIL-PRF-5606 fluid and is inadvertently serviced with MIL-PRF-83282 fluid, what action is required?

No action; the fluids are completely interchangeable
Replace only the hydraulic pump since it is most susceptible to damage
Flush the system and replace all seals, as the fluids have different seal compatibility (Correct answer)
Simply add the correct fluid to dilute the contamination

Correct answer: Flush the system and replace all seals, as the fluids have different seal compatibility

MIL-PRF-5606 and MIL-PRF-83282 have different base oils and different seal material requirements, requiring a full system flush and seal replacement if mixed.

Question 21: In a pneumatic de-icing system, what is the function of a distributor valve?

Regulate bleed air pressure to the de-ice boots to a safe working pressure
Filter moisture from bleed air before it reaches the de-ice boots
Control the flow rate of bleed air to maintain boot inflation time
Sequence the inflation and deflation of individual de-ice boot sections (Correct answer)

Correct answer: Sequence the inflation and deflation of individual de-ice boot sections

The distributor valve sequences inflation of leading-edge boot sections in the correct order to most effectively shed ice while minimizing bleed air consumption.

Question 22: What type of rivet is commonly used for aircraft assembly?

Solid rivet (Correct answer)
Split rivet
Tubular rivet
Blind rivet

Correct answer: Solid rivet

Solid rivets are extensively used in aircraft structures for strength and reliability.

Question 23: MRM (Maintenance Resource Management) training is analogous to CRM (Crew Resource Management) for pilots and focuses on:

Improving tool inventory and parts tracking systems
Certifying mechanics in advanced avionics troubleshooting
Optimizing human performance and team communication to reduce maintenance errors (Correct answer)
Standardizing shift schedules to reduce fatigue

Correct answer: Optimizing human performance and team communication to reduce maintenance errors

MRM applies CRM principles—communication, situational awareness, decision-making, and teamwork—to the maintenance environment to reduce human-error-caused accidents.

Question 24: An aircraft's pitot-static system is equipped with a pitot heat circuit. When pitot heat is ON, the ammeter shows zero current draw. What should the technician check first?

The ammeter calibration
The pitot heat element for an open circuit (Correct answer)
The pitot tube itself for blockage
The static ports for ice

Correct answer: The pitot heat element for an open circuit

Zero current draw with the heater switch ON indicates an open circuit, most likely in the heating element itself which has burned out.

Question 25: An aircraft GPS receiver shows a valid position fix but the CDI needle of the integrated course deviation indicator remains deflected. What is the most likely cause?

The aircraft is outside of GPS coverage area
A faulty CDI display unit
An incorrectly entered flight plan or destination waypoint in the GPS (Correct answer)
Insufficient GPS satellite signal strength

Correct answer: An incorrectly entered flight plan or destination waypoint in the GPS

If the GPS has a valid fix but the CDI is deflected, the most common cause is an incorrect or incomplete flight plan entry causing the unit to navigate to an unintended waypoint.

Question 26: What ethical standards guide ACS professionals in their work?

Ethical standards are suggestions, not requirements
Integrity, objectivity, confidentiality, and professional competence in all engagements (Correct answer)
Ethics only apply when clients are watching
Maximizing personal profit is the primary ethical obligation

Correct answer: Integrity, objectivity, confidentiality, and professional competence in all engagements

Professional ethics require maintaining the highest standards of integrity, objectivity, and confidentiality while continuously developing competence.

Question 27: What type of hydraulic pump is most commonly used in high-performance aircraft as an engine-driven pump due to its variable output capability?

Vane pump
Centrifugal pump
Variable displacement piston pump (Correct answer)
Gear pump

Correct answer: Variable displacement piston pump

Variable displacement piston pumps can adjust their output flow based on system demand, maintaining constant pressure while reducing heat generation and power consumption when demand is low.

Question 28: A mechanic who makes a maintenance error that goes undetected and results in an accident may face all of the following EXCEPT:

Civil lawsuit from affected parties
Automatic loss of all future FAA employment eligibility (Correct answer)
Criminal prosecution
FAA certificate action

Correct answer: Automatic loss of all future FAA employment eligibility

While mechanics can face certificate action, criminal charges, and civil liability, there is no automatic statutory bar from all FAA employment eligibility following an accident.

Question 29: What is the regulatory requirement for retaining maintenance records after the work is performed?

Records must be kept for 2 years after the work
Records must be kept until the aircraft is scrapped
Records must be kept for 1 year or until the work is repeated (Correct answer)
Records are the owner's property and may be discarded at any time

Correct answer: Records must be kept for 1 year or until the work is repeated

14 CFR 43.9 and 91.417 generally require maintenance records to be retained for 1 year or until superseded by equivalent work.

Question 30: Which document provides type-specific limitations, required equipment, and approved data sources for a certificated aircraft?

Pilot's Operating Handbook
Type Certificate Data Sheet (TCDS) (Correct answer)
Aircraft logbook
FAA Form 337

Correct answer: Type Certificate Data Sheet (TCDS)

The TCDS is the official FAA document that defines certification basis, approved configurations, required equipment, and limitations for a specific aircraft type.

Question 31: What qualifications are needed for advanced aviation mechanics practice?

Advanced practice requires no formal credentials
Advanced certifications, specialized training, demonstrated experience, and ongoing professional development (Correct answer)
No additional qualifications beyond initial certification
Only a college degree in any subject

Correct answer: Advanced certifications, specialized training, demonstrated experience, and ongoing professional development

Advanced practice requires building upon foundational knowledge through specialized certifications, targeted training, and demonstrated competence in specific areas.

Question 32: When a maintenance technician completes a required inspection entry, the record must include all of the following EXCEPT:

Date of completion
Signature and certificate number of the approving person
Description of the work performed
Owner's written authorization to perform the work (Correct answer)

Correct answer: Owner's written authorization to perform the work

14 CFR 43.9 requires the work description, date, and approving technician's signature/certificate number—owner authorization is not a required element of the maintenance entry itself.

Question 33: What is the first step in troubleshooting an aircraft system?

Disassemble the system
Replace suspected parts
Check battery voltage
Identify the problem (Correct answer)

Correct answer: Identify the problem

The first step is identifying the problem through observation or pilot reports.

Question 34: When troubleshooting an intermittent avionics failure, what is the recommended first approach?

Duplicate the failure condition, inspect connectors and wiring for corrosion or loose connections (Correct answer)
Send the unit for bench testing even if the fault cannot be duplicated
Replace the suspected unit immediately
Monitor the system over several flights before taking action

Correct answer: Duplicate the failure condition, inspect connectors and wiring for corrosion or loose connections

Intermittent avionics faults are most commonly caused by poor connections; inspecting connectors and wiring while attempting to duplicate the failure is the systematic first step.

Question 35: During engine assembly, what is the correct procedure for installing a new oil seal on a crankshaft?

Lubricate the seal lip with clean engine oil and press it in squarely to the specified depth (Correct answer)
Heat the seal to expand it before sliding it onto the crankshaft
Apply RTV sealant to the seal lip before installation
Install the seal dry to maximize friction and prevent leakage

Correct answer: Lubricate the seal lip with clean engine oil and press it in squarely to the specified depth

Oil seals should be lubricated on the sealing lip with clean engine oil to prevent lip damage during installation and initial start-up, and pressed squarely to the correct depth.

Question 36: When checking valve clearance (tappet clearance) on a reciprocating engine, the piston of the cylinder being checked must be positioned at:

TDC on the exhaust stroke
Mid-stroke on the intake stroke
TDC on the compression stroke (Correct answer)
BDC on the power stroke

Correct answer: TDC on the compression stroke

Valve clearance is checked with the piston at TDC on the compression stroke so that both intake and exhaust valves are fully closed.

Question 37: What is the purpose of a firewall shutoff valve (fuel selector/firewall valve) in an aircraft fuel system?

To filter fuel before it enters the engine
To allow the crew to stop fuel flow to the engine compartment in the event of an engine fire or fuel leak (Correct answer)
To balance fuel between left and right tanks
To regulate fuel pressure to the engine

Correct answer: To allow the crew to stop fuel flow to the engine compartment in the event of an engine fire or fuel leak

The firewall shutoff valve allows the flight crew to cut fuel flow to the engine compartment to starve a fire or stop a fuel leak from reaching the engine bay.

Question 38: What is the maximum allowable bend radius violation that can occur when bending aluminum aircraft tubing?

Minor kinks can be straightened with a tube repair tool
Kinks up to 1/16 inch depth are acceptable if within 6 inches of a fitting
No kinking is acceptable — kinked tubing must be replaced (Correct answer)
The tube may be kinked if the kink is less than 10% of the tube diameter

Correct answer: No kinking is acceptable — kinked tubing must be replaced

Any kink in aluminum aircraft tubing significantly weakens it and creates stress concentration points — kinked tubing must always be replaced, never repaired or reused.

Question 39: What is the function of a hydraulic system priority valve?

Prevent two hydraulic systems from operating at the same time
Switch automatically from one hydraulic system to another if pressure drops
Ensure flight-critical systems receive hydraulic pressure before non-critical systems during low-pressure conditions (Correct answer)
Regulate pump output pressure to a constant predetermined value

Correct answer: Ensure flight-critical systems receive hydraulic pressure before non-critical systems during low-pressure conditions

A priority valve ensures that flight-critical hydraulic consumers (such as flight controls) are served first, with non-essential systems receiving flow only when adequate pressure exists.

Question 40: How should ACS professionals approach client or stakeholder communication?

Only communicate in writing, never verbally
Use clear, professional language appropriate to the audience, confirm understanding, and document key communications (Correct answer)
Use technical jargon regardless of the audience
Communication skills are unimportant for technical professionals

Correct answer: Use clear, professional language appropriate to the audience, confirm understanding, and document key communications

Effective communication tailored to the audience's knowledge level is essential for building trust, ensuring understanding, and achieving professional objectives.

Question 41: When performing a flush repair on a composite skin, the stepped preparation method differs from a scarf by:

Using filler rather than replacement fabric plies
Applying plies on the exterior surface only
Removing material in discrete flat steps equal to one ply thickness each rather than a continuous taper (Correct answer)
Requiring autoclave cure instead of heat blanket cure

Correct answer: Removing material in discrete flat steps equal to one ply thickness each rather than a continuous taper

A stepped repair removes each ply in a flat step (typically 0.5–1 inch per step), while a scarf creates a continuous angular taper through the laminate thickness.

Question 42: Under 14 CFR Part 43, who is authorized to approve an aircraft for return to service after a major repair?

Any certificated pilot with a private certificate
A certificated mechanic holding an Airframe and Powerplant rating (Correct answer)
Only the aircraft manufacturer's representative
Any person holding a repairman certificate

Correct answer: A certificated mechanic holding an Airframe and Powerplant rating

14 CFR Part 43.7 specifies that a certificated mechanic holding the appropriate rating may approve an aircraft for return to service after a major repair.

Question 43: What is the purpose of a fuel heat exchanger on a turbine aircraft?

To chill fuel for increased density and greater range
To use fuel to cool engine oil while also preventing fuel system icing by warming the fuel (Correct answer)
To separate water from fuel using temperature differential
To increase fuel temperature for improved combustion efficiency

Correct answer: To use fuel to cool engine oil while also preventing fuel system icing by warming the fuel

The fuel-oil heat exchanger cools hot engine oil using cooler fuel as the heat sink, simultaneously warming the fuel to prevent ice crystal formation in the fuel system.

Question 44: Which component in a pneumatic system performs the same function as a hydraulic system relief valve?

Filter/separator
Pressure regulator
Pressure relief valve (Correct answer)
Check valve

Correct answer: Pressure relief valve

A pneumatic pressure relief valve protects the system from overpressure just as a hydraulic relief valve does, opening to vent excess pressure to atmosphere.

Question 45: Which NDT method is most appropriate for detecting delaminations in a carbon fiber reinforced polymer (CFRP) aircraft panel?

Ultrasonic testing (pulse-echo or through-transmission) (Correct answer)
Eddy current surface probe testing
Magnetic particle inspection
Dye penetrant inspection

Correct answer: Ultrasonic testing (pulse-echo or through-transmission)

Ultrasonic testing is the preferred method for detecting delaminations in CFRP composites because delaminations create internal interfaces that reflect ultrasonic energy, and the method works on non-conductive materials.

Question 46: When applying aircraft dope to a fabric-covered surface, runs or sags in the finish are caused by:

Using dope that is too thin or applying too heavy a coat in one pass (Correct answer)
Applying dope in cold, dry conditions
Not scuffing the previous coat before applying the next
Using too little dope per coat and moving the spray gun too fast

Correct answer: Using dope that is too thin or applying too heavy a coat in one pass

Runs and sags in aircraft dope are caused by an over-thinned mixture or applying an excessively thick coat, both of which allow the material to flow before it can flash off.

Question 47: A mechanic finds exfoliation corrosion on an aluminum alloy wing spar cap. What action is required?

Clean, treat, and determine if remaining material meets minimum thickness per SRM (Correct answer)
Treat with Alodine and apply primer immediately
Remove the spar cap and replace it
Polish smooth, apply zinc chromate, and return to service

Correct answer: Clean, treat, and determine if remaining material meets minimum thickness per SRM

Exfoliation corrosion causes layer-by-layer material loss; the mechanic must clean, treat, measure the remaining material, and compare it to the SRM minimum thickness allowable to determine airworthiness.

Question 48: According to the Dirty Dozen human factors in aviation maintenance, 'complacency' is best described as:

Overconfidence combined with reduced vigilance on familiar tasks (Correct answer)
Physical fatigue causing missed inspection steps
Failure to communicate a discrepancy to the next shift
Working beyond approved data

Correct answer: Overconfidence combined with reduced vigilance on familiar tasks

Complacency in the Dirty Dozen refers to overconfidence and reduced vigilance—often on routine, familiar tasks where errors are most likely to be overlooked.

Question 49: Aircraft fuel quantity gauges are required by FAR to be accurate to within what tolerance?

No tolerance is specified — they are advisory only
±5% of total capacity
±10% of indicated reading at all fuel levels
They must only be accurate when reading empty (zero fuel) (Correct answer)

Correct answer: They must only be accurate when reading empty (zero fuel)

FAR 23.1337 requires fuel quantity gauges to be accurate only at the empty (zero) position; at all other quantities, accuracy is advisory and may vary.

Question 50: Which part of the regulations pertains to airworthiness certification?

Part 91
Part 147
Part 21 (Correct answer)
Part 135

Correct answer: Part 21

Title 14 CFR Part 21 covers certification procedures for products and parts.

Question 51: What does a hydraulic system pressure relief valve protect against?

Filter bypass due to clogging
Pump cavitation during low-fluid conditions
Thermal expansion causing pressure spikes that exceed system design limits (Correct answer)
Fluid contamination entering the actuator

Correct answer: Thermal expansion causing pressure spikes that exceed system design limits

The pressure relief valve opens to bypass fluid back to the reservoir when system pressure exceeds the maximum design limit, protecting components from overpressure damage.

Question 52: What document governs the minimum bend radii and tube material specifications for aircraft fluid lines?

NFPA 407
FAR Part 21
AC 43.13-1B Chapter 9 and the applicable aircraft maintenance manual (Correct answer)
MIL-SPEC-5015 only

Correct answer: AC 43.13-1B Chapter 9 and the applicable aircraft maintenance manual

AC 43.13-1B Chapter 9 provides the FAA-accepted data for aircraft plumbing including bend radii, materials, flare types, and installation standards, supplemented by the AMM.

Question 53: When curing a composite repair using a heat blanket, which parameter is MOST important to monitor continuously?

Cure temperature ramp rate and hold temperature at the part surface (Correct answer)
Color change of the laminate during the cure cycle
Ambient relative humidity at the repair site
Vacuum bag pressure at the pump inlet only

Correct answer: Cure temperature ramp rate and hold temperature at the part surface

Incorrect ramp rates can cause residual stress or incomplete cure; hold temperature must be verified at the part surface because heat blankets can overshoot.

Question 54: How does technology impact modern hydraulic & pneumatic systems practices?

Technology improves accuracy, efficiency, and capabilities while requiring new skills and knowledge (Correct answer)
Technology has made professional expertise unnecessary
Only large organizations benefit from technology in this field
Technology has no impact on this field

Correct answer: Technology improves accuracy, efficiency, and capabilities while requiring new skills and knowledge

Technological advances have transformed professional practice by improving diagnostic capabilities, data analysis, documentation, and efficiency while requiring practitioners to develop new competencies.

Question 55: Which method is primarily used to detect corrosion on aircraft structures?

Ultrasonic inspection
Magnetic field mapping
X-ray imaging
Visual inspection (Correct answer)

Correct answer: Visual inspection

Visual inspection is the first method to identify corrosion before using specialized tests.

Question 56: What does a hydraulic system ground test unit (GTU) allow a technician to do?

Pressurize only the brake system independently from the main hydraulic system
Operate aircraft hydraulic systems using external ground power without running the engines (Correct answer)
Measure hydraulic fluid contamination levels during system operation
Test hydraulic systems with engines running at high power settings safely on the ground

Correct answer: Operate aircraft hydraulic systems using external ground power without running the engines

A ground test unit provides external hydraulic pressure and flow, allowing full system operation and testing without starting the aircraft engines.

Question 57: What continuing education is typically required in hydraulic & pneumatic systems?

No continuing education is ever required
Regular training to stay current with industry standards, regulations, and best practices (Correct answer)
Only education obtained before certification matters
Training is only needed in the first year of certification

Correct answer: Regular training to stay current with industry standards, regulations, and best practices

Professional fields require ongoing education to ensure practitioners stay current with evolving standards, technologies, regulations, and best practices in their specialty.

Question 58: To exercise Inspection Authorization (IA) privileges, a mechanic must hold an IA for at least how long before it must be renewed?

It never expires
24 months
12 months (Correct answer)
6 months

Correct answer: 12 months

An Inspection Authorization must be renewed annually (every 12 calendar months) by meeting one of the renewal activity requirements in 14 CFR 65.93.

Question 59: What is the primary principle behind eddy current testing?

Ionizing radiation passes through the material to expose a film
High-frequency sound waves are transmitted through the material
Fluorescent dye penetrates surface cracks and is revealed under UV light
Alternating magnetic fields induce eddy currents in conductive materials, and changes in those currents indicate defects (Correct answer)

Correct answer: Alternating magnetic fields induce eddy currents in conductive materials, and changes in those currents indicate defects

Eddy current testing works by inducing eddy currents in electrically conductive materials via alternating magnetic fields; discontinuities or material variations alter the eddy current flow, changing the coil impedance that is measured.

Question 60: Which risk assessment model used in aviation maintenance identifies likelihood and severity to prioritize hazards?

Risk matrix (likelihood × severity) (Correct answer)
DECIDE model
PAVE checklist
5M model

Correct answer: Risk matrix (likelihood × severity)

A risk matrix that evaluates both the likelihood of an event and its potential severity is the standard tool for prioritizing hazards in SMS and maintenance risk management.

FAA Aviation Mechanic – ACS Airman Certification Standards Knowledge Test

The FAA Aviation Mechanic knowledge test evaluates candidates on general aviation maintenance principles, airframe systems, fuel/hydraulic systems, and NDT inspection skills required to earn an FAA Mechanic Certificate under the Airman Certification Standards (ACS) framework.

Questions

150 min

Time Limit

70%

To Pass

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