Module 07A B1 - Maintenance Practices

Comprehensive vocabulary flashcards covering safety, workshop tools, drawings, airframe structures, systems testing, and maintenance standards for the Module 07A B1 syllabus.

Safety Lanes

Painted paths around the perimeter inside hangars used to prevent accidents and keep pedestrian traffic out of work areas.

Physiological Safety Hazards (Electricity)

Hazards that include severe burns at the entrance and exit points of the body and damage to the nervous system.

Shorting

Occurs when heat melts protective coatings on wiring, leading to increased current flow and potentially metal melting or ignition of flammable substances.

Tire Cage Guards

Safety devices that must be used when inflating aircraft tires on wheels to prevent personal injury from over-inflation, unless the tires are installed on the aircraft.

Oxygen Safety Distance

A minimum of $15\text{ meters}$ must be maintained between smoking or open flames and the work area.

Material Safety Data Sheet (MSDS/SDS)

A required $16\text{ section}$ document containing information for the safe handling, use, storage, and disposal of hazardous chemicals.

Globally Harmonized System of Classification and Labeling of Chemicals (GHS)

A United Nations system adopted by the European Union in $EC 1272/2008$ to standardize worldwide chemical documentation.

Risk Diamond (Red Segment)

The top segment of a four-color diamond representing Flammability hazards.

Risk Diamond (Health Block No. 4)

Indicates that the material is very hazardous to human health.

Drill Press Safety

Critical precautions include wearing eye protection, securely clamping all work, and stopping the machine before adjusting work or removing jams.

Fire Triangle

The three elements required for a fire to occur: Fuel, Heat, and Oxygen.

Class A Fire (US System)

Fires consisting of ordinary combustibles such as wood, paper, fabric, and trash.

Class D Fire

Fires involving combustible metals like lithium, potassium, magnesium, titanium, and zirconium.

Class K Fire (US System)

Fires involving cooking oils, recognized for their higher flash points and extinguished by turning oil into foam.

Water-Type Fire Extinguishers

Best for Class A fires; they work by depriving the fire of oxygen and cooling the burning material.

Carbon Dioxide (CO2) Extinguishers

Used for Class A, B, and C electrical fires; they extinguish by depriving the fire of oxygen and cooling the material.

Halon 104 (Carbon Tetrachloride)

A highly toxic substance with a $3$ toxicity rating, not approved for fire extinguishing use as it produces phosgene gas.

Halon 1211 (Bromochlorodifluoromethane)

A colorless, noncorrosive liquefied gas with a toxicity rating of $5$ that interferes chemically with the combustion process.

Dry Powder Extinguishers

The best type for Class D fires, working by smothering and heat absorption; common agents include sodium chloride and graphite powder.

Foreign Object Damage (FOD)

Any damage caused by loose objects (like concrete, shop towels, or safety wire) to aircraft, personnel, or equipment.

Elastometric Bearings

Helicopter components that require a specific method for rotor securing to avoid damage as specified in the maintenance manual.

Shadow Board

A tool storage concept where every tool occupies a specific location, making it easy to identify missing tools at a glance.

Tool Calibration Sticker

A label attached to a tool detailing the due date of the next calibration; no tool should be used if it is out of calibration.

Basic Size

The theoretical size from which limits of size are derived by applying allowances and tolerances.

Bilateral Tolerance

A tolerance that can be added to or subtracted from the basic size (e.g., $\text{2.5 } \text{+/- 0.05}$).

Unilateral Tolerance

A tolerance that allows variation in only one direction from the basic size.

Interference Fit

A fit where the dimensions of two parts overlap, requiring mechanical pressure for assembly.

Manufacturer's Instructions

Designed procedures used as mandatory guidance to bring about the best results in aircraft maintenance and repair.

Phillips vs. Reed & Prince Screwdrivers

Phillips screwdrivers are blunt on the end to fit a center-widened cross, while Reed & Prince are pointed for a perfect cross.

Duckbill Pliers

Pliers with thin, flat jaws used exclusively for twisting safety wire in aviation.

Combination Square Head

Utilizes a stock head with a spirit level and scriber that slides along a central groove on a scale.

Prick Punch

A tool used to place reference marks on metal or transfer dimensions from a paper pattern.

Center Punch

A punch with a heavier body than a prick punch, ground to a $60^\text{o}$ angle, used to start a twist drill.

Hooke's Law

States that the amount a beam deflects is directly related to the force applied, which is the principle behind defensive beam torque wrenches.

Torque Formula (Extensions)

$T_A = \frac{T_W \times (L + E)}{L}$ where $T_A$ is desired torque, $T_W$ is indicated torque, $L$ is wrench length, and $E$ is extension length.

Aviation Snips (Yellow)

Handle-color identified snips designed to cut in a straight line.

Hacksaw Blade Pitch

The number of teeth per inch; uses include $14$ for machine steel, $18$ for aluminum, $24$ for thick-walled tubing, and $32$ for thin-walled tubing.

Bastard Cut

A grade of file coarseness used on heavier classes of work.

Reamer

A tool used to smooth and enlarge holes to an exact size, typically after drilling $0.003$ to $0.007\text{ inch}$ undersize.

Tap and Die

A tap is used to cut internal threads in a hole; a die cuts external threads on round stock.

Kett Saw

An electrically operated, portable circular cutting saw that requires no starting hole and can start a cut anywhere on a sheet.

Cornice Brake

A sheet metal tool that allows folds to pass through the jaws from front to rear without obstruction, unlike a bar folder.

Annealing

The process of toughening steel by gradually heating and cooling it to remove temper, making it softer for forming.

Step Drill Bit

A bit that combines a pilot drill and an enlarging step into one tool to drill large holes in sheet metal.

Lip Clearance Angle

The angle at which the drill point is ground; standard for steel is $59^\text{o}$ from the axis ($118^\text{o}$ total).

Thimble and Barrel (Micrometer)

Parts used to measure work in thousandths of an inch; one thimble revolution moves the spindle $0.025\text{ inch}$.

Zerk Fitting

A lubrication fitting mounted in structure with a spring-loaded ball check valve for servicing with a grease gun.

D'Arsonval Meter Movement

A basic DC meter movement where a pointer is deflected in proportion to the current passing through a coil in a magnetic field.

Multiplier Resistance (Rm)

A series resistance added to a voltmeter movement to drop excess voltage for higher range measurements.

Megohmmeter (Megger)

A high-range ohmmeter with a hand-operated generator used to measure insulation resistance at high potential.

Oscilloscope Flyback

The period when the electron beam rapidly returns to the left side of the screen after finishing a sweep.

Line Select Key (LSK)

Buttons located next to a CDU display screen used to select menu options for BITE or system interrogation.

Time Domain Reflectometer (TDR)

Test equipment used to check for standing waves, opens, or shorts in transmission lines by displaying signal traces.

Detail Drawing

A description of a single part including specifications for size, shape, material, and manufacturing methods.

Zone Numbers

Coordinates on drawing borders (read right to left) that help locate specific parts or sections on a large drawing.

Fuselage Station 185 (FS 185)

A location identified as being $185\text{ inches}$ from the aircraft datum.

Orthographic Projection

A system using up to six possible views (front, top, bottom, rear, right/left sides) to show exact size and shape.

Isometric View

A three-dimensional pictorial drawing where lines are parallel and portions of all three views are visible.

ATA Spec 100

A standardized format for maintenance information classification using numbered chapters (e.g., Chapter $21$ for Air Conditioning).

Bow

A condition in a shaft or tube where the centerline is not straight; standard limit is often $1$ in $600$.

Electrical Wiring Interconnection System (EWIS)

Any wire or device installed to transmit electrical energy, treated as an independent airplane system.

Bonding Limit

The resistance of aircraft bond and ground connections should normally not exceed $0.003\text{ ohm}$.

Drip Loop

A wire routing technique where wires travel downward before entering a connector to trap fluids and prevent them from entering units.

Shop Head

The portion of a rivet upset during installation, ideally measuring $1.5$ times the shank diameter.

Cleco Fastener

A reusable sheet metal holder consisting of a steel cylinder and spreader bar, color-coded by size (e.g., Copper for $1/8\text{ inch}$).

37 Degrees

The required angle for aircraft tubing flares, distinguished from $45^\text{o}$ automotive flares.

Cold Flow (Hose)

Deep, permanent impressions in a flexible hose produced by the pressure of hose clamps or supports over time.

Galling

Bearing damage caused by rubbing mating surfaces where metal welds and is pulled apart in the direction of motion.

False Brinelling

Frictional corrosion damage in bearings caused by vibration while in a static state, identified by rusty lubricant coloring.

Backlash

The minute amount of 'lash' or play measured between meshing gear teeth, typically between $0.003$ and $0.004\text{ inches}$.