FAA Aviation Mechanic General (AMG) flashcards

For an object falling freely under gravity from rest, distance equals one-half the acceleration due to gravity times time squared: d = ½gt².

• g ≈ 32.2 ft/sec² near Earth's surface
• d = ½gt² (starting from rest, no air resistance)
• Solve for t: t = √(2d/g)

Memory trick: 'Half gravity times time squared' tells you how far it drops.

When an extension changes the effective lever arm of a torque wrench, the dial reading must be adjusted using TW = TE × L/(L+A) so the actual torque applied to the fastener matches the specification.

• L = wrench length, A = extension length
• Extensions in-line with the wrench increase the lever arm
• Wrench reading must be LOWER than actual desired torque when adding length

Memory trick: 'Longer arm, lower reading' — the extension steals leverage

Form 337 documents major repairs/alterations, but certificated repair stations may use their own approved records instead.

• Form 337 required for major repairs/alterations by mechanics/IA
• Part 43 Appendix B allows repair stations to use their own equivalent records
• One copy of Form 337 normally goes to FAA, one stays with aircraft records

Memory trick: 'Repair stations write their own story instead of filling out Form 337.'

A standardized box, usually in the lower right corner of a drawing, containing identifying information such as drawing number, revision, scale, date, and part name.

• Located in lower right corner by convention
• Includes drawing number, scale, revision letter, date, drafter
• Distinct from bill of materials which lists parts/quantities

Memory trick: Title block = the drawing's 'ID card' in the corner

At constant pressure, the volume of a gas is directly proportional to its absolute temperature.

• V1/T1 = V2/T2 (constant pressure)
• Temperature must be in absolute units (°R or K)
• Volume increases as temperature increases
• Used with Boyle's Law to form the Combined Gas Law

Memory trick: Charles heats the balloon and it grows — volume follows temperature.

14 CFR 91.413 requires ATC transponders to be tested and inspected per Part 43 Appendix F at intervals not exceeding 24 calendar months for operation in controlled airspace requiring a transponder.

• Same 24-month interval applies to altimeter/static system checks under 91.411
• Test must be performed by an appropriately certificated repair station, or the manufacturer
• Required for operations in most controlled airspace per 91.215

Memory trick: 'Transponder & Altimeter: Two-Year Twins' — both use 24-month cycles.

Compressed oxygen must be stored upright and secured, away from flammable materials, oil, and grease due to its strong oxidizing properties.

• Oxygen supports combustion violently; never mix with oil/grease
• Store away from flammable gases like acetylene
• Cylinders secured upright to prevent valve damage if they fall

Memory trick: Oxygen loves fire — keep it clean, upright, and alone.

Per 14 CFR 43 Appendix A, a major repair is one that if improperly done might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other airworthiness qualities.

• Wing spars, primary structure, and engine mounts are classic major repair examples
• Major repairs require an FAA Form 337 entry
• Minor repairs are all other repairs not meeting the major repair definition

Memory trick: 'Spar = structure' — anything touching primary structure is major.

As the velocity of a fluid increases, its static pressure decreases, assuming total energy remains constant.

• Basis for venturi and carburetor operation
• Also explains lift generation over an airfoil
• Total pressure = static pressure + dynamic pressure
• Velocity and static pressure are inversely related

Memory trick: Speed up the flow, pressure goes low.

A table on an engineering drawing that records the history of changes, including revision letter/number, description of change, date, and approval.

• Located near the title block
• Tracks revision letter/number sequence
• Records date and approving authority for each change

Memory trick: Revision block = the drawing's 'diary' of every change.

A human factor where an individual fails to express concerns, opinions, or objections to a decision or action, often due to hierarchy or fear of conflict, contributing to maintenance errors.

• Common in hierarchical team environments.
• Mitigated by open communication policies and CRM-style training.
• Different from lack of knowledge, which involves not knowing the correct information.

Memory trick: 'Bite your tongue, break the wing' — silence causes failure.

For a straight conductor, if the thumb points in the direction of conventional current flow, the curled fingers indicate the direction of the circular magnetic field around the wire.

• Used for conventional current (positive to negative)
• Left-hand rule used for electron flow theory
• Field lines form concentric circles around the conductor

Memory trick: 'Right hand, current flows' - thumb is current, fingers curl the field.

14 CFR 91.409(a) permits an aircraft due for a 100-hour inspection to fly up to 10 additional hours to reach a facility that can perform the inspection, with that excess time counted against the next inspection interval.

• Applies to aircraft used for hire or flight instruction for hire
• Maximum 10-hour overflight allowance
• Excess hours are subtracted from the next 100-hour interval
• Inspection must occur before further flight except to reach the maintenance location

Memory trick: 'Ten more to get her fixed' — 10 extra hours allowed to reach the shop.

An NDI method using high-frequency sound waves transmitted through a couplant to detect and locate internal or surface flaws at specific depths within a material.

• Uses pulse-echo or through-transmission techniques
• Requires a couplant (gel, oil, or water) to transmit sound into the part
• Can precisely locate flaw depth, unlike radiography which shows a 2D projection

Memory trick: Ultrasonic SHOUTS sound waves deep into metal to find hidden flaws

A human factor describing failure to recognize a hazard or situational change, such as an unexpected modification, before or during a task.

• Different from Lack of Knowledge, which is a general skills gap
• Mitigated by reviewing current maintenance records and recent alteration history
• Common in shared or previously modified aircraft

Memory trick: 'Awareness blind spot' — didn't check what changed before drilling in.

A location reference system that measures vertical distance, in inches, above (or occasionally below) a horizontal reference plane established by the manufacturer.

• Measured vertically, in inches
• Reference plane may be ground level or a fixed point below the aircraft
• Used with FS and BL to give a 3-D location on the aircraft

Memory trick: Water rises up, so Water Line goes UP the aircraft.

Ampere-hour (Ah) rating indicates how much current a battery can theoretically supply over time; time = Ah rating divided by load current.

• Ah = Amps x Hours
• Time (hours) = Ah rating / load current
• Actual discharge time is affected by temperature and discharge rate

Memory trick: 'Ah divided by Amps gives Hours' - simple division for runtime.

One of the 'Dirty Dozen' human factors; occurs when a technician lacks the necessary tools, parts, manuals, time, or personnel to properly perform a maintenance task, often leading to improvisation or shortcuts.

• Includes tool, part, and manpower shortages
• Can lead to using improper or uncalibrated equipment
• Mitigated by proper planning and inventory management
• Distinct from Lack of Knowledge (skill/training gap)

Memory trick: No proper wrench in the toolbox forces a risky guess—Lack of Resources breeds improvisation.

The frequency of the alternating current produced by a generator is determined by the number of magnetic poles and the speed of rotation, calculated as f = (P × N) / 120.

• f = frequency in Hertz (Hz)
• P = number of poles
• N = speed in revolutions per minute (RPM)

Memory trick: Poles and RPM, divide by 120, that's the Hz we've known.

A type of corrosion characterized by a general roughening of the metal surface, often appearing as a red, flaky deposit on steel or a white powdery deposit on aluminum.

• Attacks the entire exposed surface relatively evenly.
• Commonly called surface corrosion.
• On steel, it manifests as red rust; on aluminum, as a white powder.

Memory trick: Corrosion's many forms, know their tell-tale signs.

Alternating Current (AC) is the preferred welding current for aluminum due to its ability to break up the tenacious aluminum oxide layer during the reverse polarity half-cycle, ensuring a clean and strong weld.

• Aluminum oxide has a much higher melting point (3700°F) than aluminum (1220°F).
• AC provides a 'self-cleaning' action.
• DCEN (straight polarity) is generally not used for aluminum due to lack of oxide cleaning.

Memory trick: AC's dual nature cleans and penetrates for aluminum's tough skin.

Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. When finding resistance, R = V/I.

• R = Resistance (ohms Ω)
• V = Voltage (volts V)
• I = Current (amperes A)

Memory trick: V over I times R, the voltage triangle's star.

An electrical fault where current bypasses the intended path due to a low-resistance connection, often leading to excessive current and minimal voltage drop across the short.

• Low or near-zero resistance path.
• Results in very high current flow.
• Voltage drop across the short is minimal.

Memory trick: Open, Short, High-R: Three ways a circuit goes awry.

Aircraft utilize different series of stainless steel, primarily 300 and 400 series, each with distinct properties regarding magnetism, corrosion resistance, and strength characteristics.

• 300 series (austenitic): Generally non-magnetic, excellent corrosion resistance, not heat treatable for hardness.
• 400 series (ferritic/martensitic): Magnetic, some are heat treatable for strength, good corrosion resistance.
• Common aircraft uses: exhaust systems (300 series), fasteners (400 series).

Memory trick: Three hundred non-magnetic, four hundred attracts.

The characteristic open-circuit voltage produced by a single nickel-cadmium electrochemical cell, which is approximately 1.2 volts when fully charged.

• Nominal voltage is 1.2V per cell.
• Stable voltage output during discharge.
• Susceptible to memory effect if not properly discharged.

Memory trick: Lead-Acid is heavy with 2V, NiCad is lighter with 1.2V.

To operate an NPN transistor in the active region for signal amplification, the base-emitter junction must be forward-biased and the base-collector junction must be reverse-biased.

• Forward-bias allows base current to flow.
• Reverse-bias allows collector current to be controlled by base current.
• Essential for linear amplification.

Memory trick: Cut it, Act it, Sat it: Three ways a transistor can be lit.

Specific limits on the number of broken wires allowed in a certain length of aircraft control cable before replacement is mandatory, varying by cable construction type.

• 7x7 flexible cable: 3 broken wires allowed in any 1-inch length.
• 7x19 extra-flexible cable: 6 broken wires allowed in any 1-inch length.
• Broken wires near a terminal fitting are more critical.

Memory trick: Cable's broken strands, a critical number demands.

A common type of damage in composite materials where adjacent layers (plies) separate from each other, often initiated by impact, fatigue, or the expansion of trapped moisture.

• Reduces structural integrity and load-carrying capability.
• Can be caused by moisture ingress and subsequent freeze-thaw cycles.
• Often detected by tap testing, ultrasonic inspection, or thermography.

Memory trick: Delamination splits the layers, like ice in a crack.

A National Aerospace Standard bolt designed for critical structural applications requiring a precise fit and high shear strength, identified by its exact shank diameter and sometimes a shorter grip length.

• Used where precise alignment and minimal movement are crucial.
• Provides superior shear strength compared to standard AN bolts.
• Requires reaming of the hole to exact size before installation.

Memory trick: NAS bolts are precise, strong, and shear-resistant.