Aviation Maintenance Technician (AMT) General Knowledge and Practices

Comprehensive vocabulary flashcards covering general aviation maintenance technician (AMT) concepts, including corrosion control, hardware identification, technical drawing standards, tools, and materials.

Surface Preparation Post-Cleaning (Aircraft Painting)

The maintenance action where the AMT cleans the metal surface well and checks for dust, oil, or water before painting to ensure proper paint adhesion and corrosion protection.

Hydraulic O-Ring Inspection

A critical routine check for cracks and hardening to prevent hydraulic fluid leaks that could lead to system failures or loss of control.

AN430

The standard part number designation identified for a universal head rivet.

Galvanic Corrosion

The type of corrosion that occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte.

Pitting Removal on Aluminum

The procedural requirement to ensure all corrosion is thoroughly removed and inspect the area for remaining pitting before applying alodine.

Acetone (Aircraft Painting)

A solvent primarily used to wipe down surfaces before painting to ensure better adhesion.

Fisheye Defect

A paint defect characterized by small round spots where the paint pulls away, exposing the underlying surface.

Small-Hole Gauge

A measuring tool used to determine the accurate diameter of a hole approximately $1/4\text{ inch}$ by measuring the ball end of the gauge with a micrometer.

Epoxy Primer

A primer applied to bare aluminum aircraft parts before painting to ensure corrosion resistance and proper topcoat adhesion.

Micrometer Ratchet Feature

A mechanism that allows consistent measuring pressure, ensuring repeatable and accurate measurements on engine components.

Block Diagram

A type of schematic diagram that shows a simplified system overview.

Uniform Surface Corrosion

Corrosion that involves only the metal surface and appears over a wide area.

-O Temper Designation

The letter designation indicating that a metal is in its fully annealed condition.

480 Inch-Pounds Conversion

A torque value equal to $40\text{ ft-lbs}$ when converted to foot-pounds ($480 / 12 = 40$).

Spinning Nutplate Correction

The corrective action of replacing or re-riveting the nutplate to secure it before reinstalling the screw.

Annealing (Aluminum Alloys)

A thermal treatment used to soften aluminum, restoring ductility and reducing cracking during the forming of complex components.

Safety Wiring

A mechanical locking method used on aircraft to prevent nuts and bolts from loosening due to vibrations.

Sectioning Line

A type of line used on technical drawings to show exposed surfaces cut by a cutting plane.

Volatile Paint Solvents Hazard

Safety concern where solvents like acetone evaporate rapidly and can be inhaled or absorbed without proper personal protective equipment.

Fretting Corrosion

The form of corrosion typically associated with the telltale visual indicator known as "smoking rivets."

Blind Rivet

A mechanical fastener designed for installation when there is no access to the blind or back side of the joint for bucking.

Conductivity

The physical property of a metal that enables it to carry heat or electricity.

Thickness Gauge

A precision tool used to measure clearance between a surface plate and a relatively narrow surface being checked for flatness.

Orange Peel Remedy

The corrective step of checking and adjusting paint viscosity, thinner ratio, and spray technique according to specifications before repainting.

"DD" Bolt Marking

Identification marking on an aircraft bolt head indicating that the bolt is manufactured from aluminum alloy.

Non-Ferrous Metals Properties

Material characteristics of metals like aluminum and titanium requiring unique handling, specialized repair methods, and corrosion prevention to maintain aircraft performance.

Vernier Scale

An auxiliary graduation scale on calipers and micrometers designed to allow for more precise readings.

Acrylic Panel Scratch Remedy

The recommended practice of polishing out light surface scratches using an approved plastic polish to restore optical visibility and prevent crack propagation.

Polyurethane

A durable topcoat formulation known for providing a tough, chemical-resistant finish on aircraft surfaces.

Tempering (Steel)

A heat treatment process performed after hardening steel to reduce brittleness and improve toughness.

Severe Galvanic Corrosion Condition

The surface area ratio where galvanic corrosion is most rapid and severe: when the surface area of the anodic metal is smaller than the surface area of the cathodic metal.

Sandwich Panels

Structural composite panels used in aircraft construction primarily to increase strength while minimizing weight.

Half Section Drawing

An aircraft drafting view that helps a technician see both the inside and outside of a symmetrical part simultaneously.

Plastic Media Blasting (PMB)

A surface preparation technique used to gently remove paint and rust without damaging base metal surfaces.

Orthographic Projection

A drafting method where one-view, two-view, and three-view drawings are the most common representations of an object.

Aircraft Registration Number Height

The regulatory dimensional requirement stating that registration numbers on most aircraft must typically be at least $12\text{ inches}$ tall.

Notes on Maintenance Drawings

Drafting annotations that provide technicians with additional instructions and specifications not easily shown graphically.

AN470A4-4

A part number identifying an icebox rivet that requires low-temperature storage prior to driving.

Scriber

A pointed hand tool used to mark precise, fine layout lines on metal surfaces before cutting or drilling.

Exploded View Drawing

An illustration showing assembly components separated to illustrate how individual parts align and fit together.

Zone Numbers (Aircraft Blueprints)

Reference numbers along blueprint borders used to locate specific parts, sections, and views on large engineering drawings.

Magnesium (Galvanic Hierarchy)

The most chemically active and anodic metal when compared to cadmium and 7075-T6 aluminum alloy.

Common Aircraft Paints

Polyurethane and epoxy, which are the two most commonly used paint and coating types on aircraft structures.

Anode (Galvanic Cell)

The active electrode material that corrodes as electrons flow from it to the cathode during an electrochemical reaction.

Primary Purpose of Aircraft Paint

To protect aircraft structural surfaces from environmental corrosion.

Torque Wrench Extension Formula

The equation used to find the required wrench indication: $\frac{T \times L}{L + E}$, which yields $633.3\text{ ft-lbs}$ for $T = 700\text{ ft-lbs}$, $L = 66.5\text{ in}$, and $E = 7\text{ in}$.

Alclad Skin Advantage

A metallurgical cladding that provides a corrosion-resistant pure aluminum outer layer while maintaining the strength of the underlying aluminum alloy core.

"H" Suffix in AN6H34

Part number code indicating that the bolt head is drilled for safety wire installation.

Tolerance (Aircraft Blueprints)

The difference between extreme permissible dimensions that a manufactured part may possess and still remain acceptable.

Dimpled Head Rivet

An aircraft rivet manufactured from 2117 aluminum alloy, identified by a small indention or dimple on its head.

Filiform Corrosion

A localized form of corrosion that manifests as fine, "worm-like" filament tracks beneath paint films caused by trapped moisture.

Hardness (Mechanical Property)

A metal property evaluated during mechanical testing by assessing the material's resistance to permanent indentation or denting.

Field Rivet

A standard aircraft solid rivet designated by code AD and manufactured from 2117 aluminum alloy.

Non-Approved Cleaning Compounds Risk

The chemical danger of inducing hydrogen embrittlement in high-strength metal structures by using unapproved cleaners.

Aircraft "N" Numbers

Identification markings prominently displayed to legally identify the aircraft's country of origin and specific registration.

Revision Block Verification

The mandatory administrative check confirming that a maintenance drawing is current, authorized, and accurate before starting work.

"T" Temper Designation

A metallurgy letter designation indicating that an aluminum alloy has been heat treated.

Aluminum Rivets in Magnesium Skin

A dissimilar metal combination that creates galvanic corrosion between the metals, progressively weakening the structural joint.

Thermal Expansion

The physical property describing the dimensional expansion and volumetric increase of a metal when heated.

Sodium Dichromate Solution

A chemical conversion treatment specifically noted as a milder passivating option for treating aluminum components with complex shapes.

Aircraft Bolt Diameter Increments

The fractional measurement unit of $1/16\text{ inch}$ used to designate standard aircraft bolt shank diameters.

Safety Data Sheet (SDS)

An official chemical information document providing mandatory handling, toxicity, and emergency safety instructions for materials used in corrosion control.

Wing Skin Repair Sketching (Initial Step)

The fundamental first step in laying out a repair drawing: to block in the views.

Steel Wool Hazard (Anodized Aluminum)

An aggressive mechanical cleaning abrasive known to cause severe surface damage and corrosion site initiation on anodized aluminum films.

Alclad Aluminum

Composite sheet metal consisting of pure aluminum surface layers metallurgically rolled over an aluminum alloy core to achieve corrosion resistance.

"A" Suffix on Bolt Part Numbers

A standard military/aerospace hardware code indicating that the bolt shank is undrilled (lacks a cotter pin hole).

Thickness Gauge (Piston Ring Check)

A feeler gauge instrument used to measure the side clearance between a piston ring and its corresponding piston groove.

Tap

A fluted cutting tool designed to cut or recondition internal screw threads inside a pre-drilled hole.

Corrosion (Aviation Definition)

The natural electrochemical deterioration process commonly described in aviation as metal returning to its natural state.

Revision Block Location

The standardized location reserved for engineering change history on an aircraft blueprint: the upper right corner.

Stiff Nonmetallic Brush

The approved tool used to mechanically scrub away corrosion products from magnesium alloys without introducing galvanic contamination.

Class 3 Thread Fit

The standard dimensional tolerance classification describing the medium fit used on aerospace structural bolt threads.

Shaft Precision Measurement Tool

A micrometer, selected over rulers and calipers because it provides the highest level of precision required for tight outside diameter tolerances.

Topcoat Peeling on Cured Primer

An adhesion failure occurring because the epoxy primer cured fully over several days and required scuff sanding for mechanical bonding.

Nomogram

A graphical calculating chart designed to determine approximate numerical operational values quickly without requiring a calculator.

$7 \times 19$ Control Cable

A multi-strand aircraft steel control cable classified as extra-flexible for use over tight pulleys.

Seals and Gaskets

Elastomeric and mechanical packing components designed to prevent fluid leaks and exclude contaminants from aircraft systems.

Solid Rivet Diameter Increments

The fractional measurement unit of $1/32\text{ inch}$ used to specify the shank diameter of solid aircraft rivets.

Blushing (Milky Paint Defect)

A cloudy, milky finish defect caused when relative humidity in the paint booth is excessively high during application, causing moisture trapping.

Aluminum Alloy Bolt Head Marking

A distinctive physical marking consisting of a double dash stamped or raised on the bolt head.

Chisel

A hardened steel striking tool used to shear off stuck fasteners or trim ragged sheet metal edges.

Aluminum Oxide vs. Iron Oxide

A metallurgical difference where aluminum oxide forms a tight, stable protective barrier, whereas iron oxide flakes away and exposes more bare metal to continuous corrosion.

Phantom Lines

Drafting lines composed of long and short dashes used to show the alternate positions of moving components or where a missing part would fit.

Lock Washer Omission

A dangerous assembly error where a nut may loosen due to cyclic operational vibration, leading to complete component failure.

Small Shaft Measuring Tools

A caliper (or a micrometer when high precision is demanded), identified as the appropriate instrument for checking small shaft diameters.

2024 Aluminum Alloy

The specific high-strength heat-treated aluminum alloy most commonly selected and used for aircraft skin panels.