FAA Aviation Mechanic General (AMG) flashcards

A line, often drawn jagged or S-shaped, used on a drawing to indicate that a uniform middle portion of a long part has been left out to conserve space, while overall length is still dimensioned.

• Used for long, uniform parts like spars, shafts, tubing
• Jagged (freehand) or S-shaped (long break) style
• True overall dimension is still specified despite the omission

Memory trick: Break line — imagine literally snapping the part in the middle and pushing the ends together to save paper.

States that the induced EMF in a conductor is directly proportional to the rate of change of magnetic flux through the circuit.

• Faster relative motion increases induced EMF
• Basis for generator and transformer operation
• Formula: EMF = -N(dΦ/dt)

Memory trick: Faster flux change = bigger spark — speed matters, not wire length.

Period (T) is the time for one complete AC cycle and is the mathematical reciprocal of frequency (f): T = 1/f.

• Formula: T = 1/f (seconds)
• Aircraft AC systems commonly use 400 Hz
• Higher frequency means shorter period

Memory trick: Frequency and period are reciprocal dance partners — one up, the other down.

The opposition an inductor presents to AC current flow, which increases with frequency and inductance.

• Formula: XL = 2πfL
• Directly proportional to frequency and inductance
• Measured in ohms

Memory trick: Inductors 'resist change' more as frequency climbs — XL rises with f and L.

In a series circuit, total resistance is the sum of all resistances because current has only one path to follow.

• Rt = R1+R2+R3...
• Current is the same through all components
• Voltage drops divide across resistors
• Adding resistors increases total resistance

Memory trick: Series resistors line up like train cars — just add their lengths.

The turning effect of a weight about the datum, calculated as weight multiplied by its arm (distance from datum).

• Moment = Weight × Arm
• Expressed in inch-pounds (in-lb)
• Used to find total moment for CG calculations

Memory trick: Moment = Weight times Wobble-distance (arm).

14 CFR 65.91 governs Inspection Authorization: it is effective until March 31 of each odd-numbered year and may be renewed by meeting activity requirements, a refresher course, or an oral/practical test.

• IA expires March 31 of odd-numbered years, a two-year cycle
• Renewal requires meeting at least one of several activity criteria in the preceding 24 months
• Alternative: complete an FAA-approved refresher course or pass an oral/practical retest

Memory trick: 'Odd years end it' — IA always dies on March 31 of an odd year.

One of the FAA's twelve human factors causing maintenance errors, referring to failure to pass on necessary information between individuals, shifts, or departments.

• Common at shift changes and job handoffs.
• Mitigated by written logs and verbal briefings.
• Part of the 'Dirty Dozen' maintenance human factors model.

Memory trick: 'Silent shift, sunk ship' — no talk means trouble.

An FAA document listing the approved design, engine/propeller combinations, weight and balance limits, and other airworthiness specifications for a certificated aircraft, engine, or propeller.

• Issued as part of the type certification process.
• Used to verify approved parts, configurations, and limits.
• Essential reference for determining major vs. minor alteration status.

Memory trick: 'TCDS = the recipe card' for what's legally allowed on the aircraft.

A four-digit code identifying alloy composition; the first two digits indicate alloy type and the last two indicate approximate carbon content in hundredths of a percent.

• 10xx = plain carbon steel
• 41xx = chromium-molybdenum alloy steel
• Last two digits = approximate carbon percentage x100
• 4130 and 4340 are common aircraft structural steels

Memory trick: "Forty-one, forged with chrome and moly, tough as can be."

A human factors hazard where overconfidence from repeated successful outcomes leads to reduced awareness of risk.

• One of the FAA/Transport Canada 'Dirty Dozen' maintenance error factors
• Often caused by repetitive, routine tasks
• Countered by following checklists regardless of experience level

Memory trick: 'Dozen dangers dwell in every dull, doubted duty.'

A semiconductor diode conducts current in only one direction, allowing it to convert AC into pulsating DC through rectification.

• Diode has a PN junction
• Forward bias allows current flow
• Reverse bias blocks current flow
• Used in rectifier circuits to produce DC from AC

Memory trick: A diode is a one-way street sign for electrons.

A procedure using only the starter (no fuel or ignition) to rotate a turbine engine and purge residual fuel after an aborted/hung start.

• Fuel and ignition are OFF during the run
• Clears unburned fuel/vapor from combustion section
• Prevents tailpipe fire on next start attempt

Memory trick: Dry motoring = 'dry cleaning' the engine before trying again.

The minimum distance from a rivet hole center to the sheet edge, typically 2 times the rivet shank diameter, to prevent edge cracking or rivet pull-through.

• Minimum edge distance = 2 × rivet diameter
• Applies to standard/universal head rivets
• Insufficient edge distance risks skin cracking under load

Memory trick: Two diameters from the edge keeps the rivet from a wedge (crack)

The ratio of true power (watts) to apparent power (volt-amps) in an AC circuit, indicating how effectively current is converted into useful work.

• Formula: PF = True Power / Apparent Power
• Apparent Power = Voltage x Current (VA)
• PF = 1.0 only in purely resistive circuits

Memory trick: True power is the 'useful work,' apparent power is the 'total effort' — PF shows efficiency.

The amount of material consumed by a bend, calculated with BA = (0.01743R + 0.0078T) × N, used to determine flat pattern layout length for sheet metal fabrication.

• R = bend radius, T = material thickness, N = bend angle in degrees
• Used with setback to determine flat pattern layout
• Essential for accurate sheet metal part fabrication

Memory trick: 'Bend Allowance eats up the flat length'

A method using the left hand (electron flow theory) to determine the direction of induced current when a conductor moves through a magnetic field.

• Thumb = direction of motion
• Forefinger = direction of magnetic field
• Middle finger = direction of induced current
• Used to predict generator output polarity

Memory trick: Thumb moves, Forefinger points the field, Middle finger shows the current — 'FBI' backwards for electron flow.

In a compound gear train, the overall speed ratio is the product of the individual gear stage ratios.

• Single stage ratio = driven teeth / drive teeth
• Compound ratio = product of all stage ratios
• Output speed = Input speed ÷ total ratio

Memory trick: 'Multiply each mesh to find the total squeeze' on shaft speed.

14 CFR 43.16 requires that maintenance, preventive maintenance, rebuilding, or alteration be performed in accordance with the ICA prepared by the manufacturer or STC holder.

• ICA are issued by TC, PMA, or STC holders
• Compliance is mandatory under 43.16
• Applies to alterations, appliances, and parts
• Deviations require FAA-approved alternate data

Memory trick: 'ICA is the instruction manual for the modification—follow it like gospel.'

A location reference expressed as the horizontal distance, in inches, from the aircraft's datum along the longitudinal axis.

• Measured parallel to the longitudinal axis
• Expressed in inches from datum
• Complements Buttline (lateral) and Waterline (vertical) references

Memory trick: FS = 'Forward/aft Slide' along the fuselage length.

Raised or recessed symbols stamped on a rivet's manufactured head identify its aluminum alloy composition per AC 43.13-1B.

• No marking = 1100/3003 pure aluminum
• Recessed dot = 2117-T4 (AD), usable at room temperature
• Raised dot = 2024-T3 (DD), must be refrigerated until driven

Memory trick: 'Dot Up = Freeze it, Dot In = Use it'

A heat treatment applied after electroplating high-strength steel parts to drive out absorbed hydrogen and prevent delayed brittle cracking.

• Required for steel parts with tensile strength above ~220,000 psi
• Must occur within a specified time after plating (often within hours)
• Baking temperature is typically 375-400°F for several hours
• Failure to bake can cause sudden, delayed cracking under load

Memory trick: "Plate then bake, or the bolt will break."

An absolute temperature scale used in gas law calculations where 0°R equals absolute zero; found by adding 460 to a Fahrenheit reading.

• °R = °F + 460
• Absolute zero = 0°R = -460°F
• Used with gas laws requiring absolute temperature in English units

Memory trick: 'Rank it up 460' — add 460 to Fahrenheit for Rankine.

Procedure requiring the aircraft to be leveled and jacks placed on solid, level surfaces before lifting to prevent instability.

• Use leveling device on longitudinal and lateral axes
• Jacks must be rated for aircraft weight and placed at designated jack points
• Never work under a jacked aircraft without additional support (safety stands)

Memory trick: Level it, lock it, lift it safely.

The volume of a sphere is calculated as V = (4/3)πr³, where r is the radius; used for spherical accumulators and tanks.

• Radius = half the diameter
• V = (4/3)πr³
• π ≈ 3.1416 for calculations

Memory trick: 'Four-thirds pi r cubed' — the sphere's secret formula.

A nondestructive testing method that reveals surface-breaking defects by applying penetrant, removing excess, then applying developer to draw the penetrant back out for visibility.

• Works on nonporous ferrous and nonferrous materials
• Steps: clean, apply penetrant, dwell, remove excess, apply developer, inspect
• Developer is critical to reveal fine surface cracks

Memory trick: 'Clean, Color, Wait, Wipe, Powder, Peek'

AN fitting and tubing dash numbers represent the outside diameter of the tube in sixteenths of an inch.

• Dash number ÷ 16 = OD in inches
• -4 = 1/4 inch, -6 = 3/8 inch, -8 = 1/2 inch
• Used consistently across AN fittings and hose sizing
• Helps technicians quickly identify tube size without measuring

Memory trick: Dash number over sixteen tells you the tube's true size.

A plain steel or aluminum washer placed under a bolt head or nut to distribute bearing load and protect the structure surface, and sometimes used for shimming grip length.

• Distributes clamping load over wider area
• Protects soft materials from nut/bolt rotation damage
• Can be used to adjust bolt grip length
• Does not provide anti-rotation locking by itself

Memory trick: "Washer wide, load divide."

To find a component's quantity in a mixture, multiply the total volume by the required percentage expressed as a decimal.

• Convert percentage to decimal by dividing by 100
• Component volume = Total volume × decimal percentage
• Remaining volume = Total volume − component volume

Memory trick: 'Quarter of the whole' — 25% means take one-fourth of the total volume.

To convert a tank's cubic volume to gallons, calculate volume in cubic feet and multiply by 7.48 gallons per cubic foot.

• 1 cubic foot = 7.48 U.S. gallons
• Convert all dimensions to feet before calculating volume
• Volume of rectangular tank = length × width × height
• Common in fuel and hydraulic reservoir sizing problems

Memory trick: Feet cubed times 7.48 turns a box into gallons.

For a fixed volume of gas, pressure is directly proportional to absolute temperature: P1/T1 = P2/T2.

• Volume must remain constant
• Temperature must be converted to absolute scale (Rankine or Kelvin)
• Used to predict pressure changes in sealed containers when heated

Memory trick: 'Pressure follows heat when volume can't retreat' — Gay-Lussac's rule.

Physical or mental exhaustion reducing a technician's alertness and performance, often from long hours or inadequate rest.

• Increases risk of missed steps and errors.
• Mitigated by duty-time limits and adequate rest periods.
• One of the twelve maintenance human factors identified by the FAA/industry.

Memory trick: 'Tired hands, torque forgotten.'

A table on an engineering drawing listing every part number, description, material, and quantity required for the assembly.

• Lists part number and description
• Shows quantity required per assembly
• Usually placed above the title block or on a separate sheet

Memory trick: Bill of Materials = grocery list for the assembly.

The area forward of a running turbine engine where suction can ingest loose objects, tools, or personnel, causing FOD or injury.

• Danger zone distance varies by engine size and power setting
• Personnel and loose equipment must stay clear of marked intake hazard areas
• Jet blast danger zone is aft of the exhaust, opposite of intake hazard

Memory trick: Front sucks, back blows — know your zones before you go.

Defines that a mechanic may perform and approve for return to service only maintenance within the scope of the rating(s) held (Airframe and/or Powerplant).

• Airframe rating covers structure, flight controls, and related systems.
• Powerplant rating covers engines, propellers, and related accessories.
• A mechanic holding both ratings may work on both categories.

Memory trick: 'Airframe = skin, Powerplant = spin (engine/prop).'

A human factor describing failure to work cooperatively and coordinate tasks/responsibilities with others on a shared job.

• Different from Lack of Communication, which is about information transfer
• Leads to duplicated work or, as here, unassigned/unverified tasks
• Mitigated by clearly defined roles and task assignment briefings

Memory trick: 'Two hands, no coordination' — both assume, neither confirms.

A standardized method of dividing an aircraft into numbered zones so maintenance personnel can quickly locate structure, systems, and components referenced in manuals.

• Zones are independent of dimensioned drawings—purely for location reference
• Major zone groups: 100/200 fuselage, 300 empennage, 400 powerplant, 500/600 wings, 700 landing gear, 800 doors
• Zone charts are found in the maintenance manual's introduction section

Memory trick: '3 for the Tail' — three hundred points to the empennage

Lightweight, high-strength metal alloys with excellent corrosion resistance and high-temperature performance, used for firewalls, exhaust components, and structural fittings.

• Higher strength-to-weight ratio than steel or stainless steel
• Excellent corrosion and heat resistance
• Difficult to machine and weld due to reactivity

Memory trick: Titanium: Tough, Thermal-resistant, and Trim in weight

The grip length of a bolt should closely match the thickness of the material being joined so that the smooth shank—not the threads—bears within the joint; washers may be added to compensate for slight mismatches.

• Grip length = unthreaded shank length of bolt
• Should match or slightly exceed material thickness
• Washers can be added under the nut to fill gaps (typically up to 3)
• Threads must never bear within the clamped material

Memory trick: "Shank in the stack, threads stay back."

A form of corrosion that progresses along the grain boundaries of a metal, often caused by improper heat treatment, and is difficult to detect visually despite significant internal weakening.

• Often results from improper quenching/heat treatment
• Can lead to exfoliation corrosion if unchecked
• Hard to detect with visual inspection alone; needs NDT

Memory trick: 'Grain boundaries crumble quietly inside'

14 CFR 43.11 specifies what must be recorded when a required inspection (annual, 100-hour, progressive, etc.) is performed, separate from general 43.9 maintenance entries.

• Must include type of inspection, date, and aircraft total time in service
• Must include signature, certificate number, and kind of certificate of person approving/disapproving return to service
• If unairworthy, must include a list of discrepancies given to the owner/operator

Memory trick: 'Type, Time, Total, Signature' — the four T's of an inspection entry.

The smallest radius to which a sheet metal part can be bent without cracking, determined by material thickness, alloy, and temper.

• Exceeding (going tighter than) minimum radius causes outer-surface cracking
• Found in aircraft structural repair manuals per alloy/thickness
• Thicker/harder materials require larger minimum radii
• Directly affects bend allowance and setback calculations

Memory trick: "Bend too tight, crack in sight."

National Aerospace Standard hardware manufactured to closer tolerances and higher strength than standard AN hardware, used in critical structural applications.

• NAS = tighter tolerances than AN
• Often used in high-load, critical joints
• MS (Military Standard) parts often replaced AN designations for standardized simplified hardware

Memory trick: NAS = 'Narrow And Snug' tolerances for critical joints

A theoretical convention stating current flows from the positive terminal through the external circuit to the negative terminal, opposite to actual electron movement.

• Used on most schematic diagrams
• Opposite direction of electron flow theory
• Electron flow is negative to positive externally

Memory trick: Conventional current is 'positive thinking' — it flows from + to -.

The time from the moment an aircraft leaves the surface of the earth until it touches down at the next point of landing; used to compute inspection and overhaul intervals.

• Also called 'flight time' in this context.
• Excludes taxi time before takeoff and after landing.
• Basis for 100-hour, annual, and component life calculations.

Memory trick: 'Wheels up to wheels down' counts, not taxi time.

A nondestructive testing method that induces alternating currents into a conductive material to detect surface and near-surface cracks, corrosion, or conductivity changes.

• Works only on electrically conductive materials
• Detects surface and near-surface flaws in metals
• Effective on nonferrous metals like aluminum
• Can often be performed without removing paint coatings

Memory trick: "Eddy currents swirl and stall at every crack."

One of the 'Dirty Dozen' human factors; occurs when attention is diverted from a maintenance task, often causing steps to be missed or forgotten.

• Common cause of incomplete/incorrect maintenance
• Mitigated by task markers or 'stop and review' habits
• Interruptions should trigger a recheck of the last steps performed
• Distinct from complacency (overfamiliarity) or fatigue (tiredness)

Memory trick: Twelve gremlins sabotage maintenance quality—Distraction pulls your eyes away mid-task.

A tolerance that allows variation in only one direction from the basic dimension, expressed as plus or minus but not both.

• +0.005/-0.000 allows oversize only
• Basic dimension is the minimum acceptable size in this example
• Used when undersizing would cause a fit or function problem

Memory trick: Unilateral = 'one-way street' for size variation.

A transformer changes voltage between primary and secondary windings based on the ratio of turns, following Vs/Vp = Ns/Np.

• Step-up transformers have more secondary turns than primary
• Step-down transformers have fewer secondary turns than primary
• Vs = Vp × (Ns/Np)
• Power is conserved: Vp×Ip = Vs×Is (ideal transformer)

Memory trick: More turns, more volts — fewer turns, fewer volts.

Fire extinguishers are matched to fire class: A (ordinary combustibles), B (flammable liquids), C (electrical), D (combustible metals).

• Class C fires require non-conductive agents like CO2 or Halon
• Water/foam extinguishers are dangerous on live electrical equipment
• Class D powder agents smother burning metals like magnesium or titanium

Memory trick: 'C' is for Circuits — keep it dry, keep it CO2.

Places the primary responsibility for maintaining an aircraft in airworthy condition, including compliance with ADs, on the owner or operator, not solely on the mechanic performing the work.

• Owner must ensure maintenance is performed by authorized persons.
• Compliance with ADs is part of this responsibility.
• Mechanic responsibility for workmanship exists separately under 43.12/43.13.

Memory trick: 'Owner owns the outcome' even if a mechanic did the work.

A dimensioning method that specifies the maximum and minimum allowable size directly as two numbers (e.g., 0.497–0.500), without stating a separate nominal value and tolerance.

• States high limit and low limit directly
• No separate plus/minus value shown
• Common on precision machined dimensions

Memory trick: Limit dimensioning gives you the fence posts (min and max) directly, no math needed.

An additional certification for A&P mechanics that authorizes annual inspections and approval of major repairs/alterations.

• Requires 3 years of active A&P experience to qualify
• Grants privilege to perform annual and progressive inspections
• Must be renewed every 2 years by activity or retesting

Memory trick: 'IA = Inspects Annually' — the extra rating for annual sign-offs.

A drawing that completely describes a single part, including dimensions, tolerances, material, and finish, sufficient for manufacture.

• Shows one part only
• Includes all dimensions and tolerances
• Contrasts with assembly drawings, which show multiple parts

Memory trick: Detail = one part, all the fine print.

Formula used to convert Fahrenheit readings to Celsius for technical calculations.

• C = (F − 32) × 5/9
• F = (C × 9/5) + 32
• Freezing point: 32°F = 0°C
• Boiling point: 212°F = 100°C

Memory trick: Subtract 32, then multiply by 5/9 to go from F to C.

An increase in hardness and decrease in ductility of a metal caused by repeated plastic deformation (cold working), which can lead to cracking if working continues.

• Also called strain hardening or cold working effect
• Repeated bending/straightening is a common cause
• Annealing (heat treatment) can restore ductility

Memory trick: Bend a paperclip enough times and it work-hardens until it snaps

In a block-and-tackle system, mechanical advantage equals the number of rope segments supporting the movable load, reducing the effort force needed.

• MA = number of supporting rope segments
• Effort = Load ÷ MA
• More supporting segments = less force but more rope pulled

Memory trick: 'Count the strands holding the weight' to find your force savings.

Corrosion that occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte, causing the more anodic (active) metal to corrode.

• Requires dissimilar metals, electrical contact, and an electrolyte
• The more active metal in the galvanic series corrodes preferentially
• Greater difference in galvanic series = more severe corrosion

Memory trick: 'Different metals, wet weather, worse together' - galvanic corrosion needs a couple and moisture

The sum of all voltage drops around a closed series loop equals the applied source voltage.

• Applies to any closed loop circuit
• Sum of drops = source EMF
• Used to find unknown voltage drops in series circuits

Memory trick: What goes up (source) must come down (drops) — it all balances.

A corrosion-resistant aluminum sheet made by bonding a thin layer of pure aluminum to the surface of a stronger, less corrosion-resistant aluminum alloy such as 2024-T3.

• Pure aluminum cladding is anodic, sacrificing itself to protect the core
• Must not be sanded/polished through during repairs or corrosion of the core alloy can begin
• Commonly used on exterior skins for corrosion resistance

Memory trick: 'Alclad is the sacrificial shield' - pure aluminum takes the corrosive hit first