# AC 43.13-1B CHG 1 — Acceptable Methods, Techniques, and Practices: Aircraft Inspection and Repair # Appendices: Glossary, Acronyms, Metric Prefixes Source: FAA Advisory Circular 43.13-1B CHG 1. Page markers like [AC 43.13-1B p. 7-9] give the AC page; paragraph numbers (e.g. 7-40.) appear in the text. Tables are reproduced with | between columns. [AC 43.13-1B p. App 1] Appendix 1 ## APPENDIX 1. GLOSSARY The following words and terms represent some of those that are often encountered in the field of aviation. For a more complete list of definitions, a mechanic or technician should consult an aviation dictionary. -A- Abrasion resistant PTFE — A solid insulation wall of PTFE with hard, nonconductive grit positioned midway in the wall thickness, and significantly improves the resistance of the PTFE material to damage from wear. Acetylene — Gas composed of two parts of carbon and two parts of hydrogen. When burned in the atmosphere of oxygen, it produces one of the highest flame temperatures obtainable. Acetylene regulator — Manually adjustable device used to reduce cylinder pressure to torch pressure and to keep the pressure constant. They are never to be used as oxygen regulators. Adherend — One of the members being bonded together by adhesive. Airworthiness Directive— A regulation issued by the FAA that applies to aircraft, aircraft engines, propellers, or appliances, when an unsafe condition exists and that condition is likely to exist or develop in other products of the same type design. Airworthy — Is when an aircraft or one of its component parts meets its type design and is in a condition for safe operation. Ambient light — The visible light level measured at the surface of the part. Ampere (amp) — The basic unit of current flow. One A is the amount of current that flows when a difference of potential of 1 V is applied to a circuit with a resistance of coulomb per second. Antenna — A device designed to radiate or intercept electromagnetic waves. Anti-tear strips — Strips of fabric of the same material as the airplane is covered with, laid over the wing rib under the reinforcing tape. Apparent power — The product of volts and amperes in AC circuits where the current and voltage are out of phase. Appliance — Any instrument, mechanism, equipment, part, apparatus, appurtenance, or accessory, including communications equipment, that is used or intended to be used in operating or controlling an aircraft in flight, is installed in or attached to the aircraft, and is not part of an airframe, engine or propeller. [AC 43.13-1B p. App 2] Appendix 1 Arm — A measurement of distance, in inches, feet, etc., used in weight and balance calculations. Normally only the longitudinal arm is of practical importance. The three axial arms are longitudinal arm, lateral arm, and vertical arm. Automatic direction finder (ADF) — A radio receiver utilizing a directional loop antenna that enables the receiver to indicate the direction from which a radio signal is being received; also called a radio compass. Automatic flight control system (AFCS) — A flight control system incorporating an automatic pilot with additional systems such as a VOR coupler, an ILS approach coupler, and an internal navigation system that is fully automatic, so the aircraft can be flown in a completely automatic mode. Avionics — The science and technology of electronics as applied to aviation. Azimuth — Angular distance measured on a horizontal circle in a clockwise direction from either north or south. -B- Balance — The condition of stability which exists in an aircraft when all weight and forces are acting in such a way as to prevent rotation about an axis or pivot point. Base metal — The metal to be welded, brazed, soldered, or cut. Black light — Electromagnetic radiation in the near ultraviolet range of wavelength. Blade station — Is a reference position on a blade that is a specified distance from the center of the hub. Bond — The adhesion of one surface to another, with or without the use of an adhesive as a bonding agent. Bonding — A general term applied to the process of electrically connecting two or more conductive objects. In aircraft, the purpose of bonding (except as applied to individual connections in the wiring and grounding systems) is to provide conductive paths for electric currents. This is accomplished by providing suitable low-impedance connections joining conductive aircraft components and the aircraft structure. Another purpose of bonding is to ensure the safe passage of current caused by lightning or static electricity through the aircraft structure. Borescope — A long, tubular optical instrument designed for remote visual inspection of surfaces. Brashness — A condition of wood characterized by low resistance to shock and by an abrupt failure across the grain without splintering. [AC 43.13-1B p. App 3] Appendix 1 Braze welding — A welding process variation in which a filler metal, having a liquidus above 450 °C (840 °F) and below the solidus of the base metal is used. Unlike brazing, in braze welding the filler metal is not distributed in the joint by capillary action. Brazing — The joining of two pieces of metal by wetting their surface with molten alloy of copper, zinc, or tin. Bus or bus bar — Solid copper strips to carry current between primary and secondary circuits; also used as jumpers. Butt joint — A joint between two members aligned approximately in the same plane. Butyrate dope — A finish for aircraft fabric consisting of a film base of cellulose fibers dissolved in solvents with the necessary plasticizers, solvent, and thinners. -C- Cable (electrical) — Assembly of one or more conductors within an enveloping protective sheath so constructed as to permit use of conductors separately or in a group. Calibration — A set of operations, performed in accordance with a definite document procedure, which compares the measurements performed by an instrument or standard, for the purpose of detecting and reporting, or eliminating by adjustment, errors in the instrument tested. Center of gravity — That point about which the aircraft would balance if suspended. For field weight and balance purposes/control, the center of gravity is normally calculated only along its longitudinal axis (nose to tail), disregarding both the lateral and vertical location. Certification — Implies that a certificate is in existence, which certifies or states a qualification. Check — A lengthwise separation of the wood, the greater part of which occurs across the rings of annual growth. Chemical conversion coating (Specification MIL-C-81706) — Is a chemical surface treatment used on aluminum alloys to inhibit corrosion and to provide a proper surface for paint finishing. Chord — An imaginary straight line joining the leading and trailing edges of an airfoil. Circuit — A closed path or mesh of closed paths usually including a source of EMF. Circuit breaker — A protective device for opening a circuit automatically when excessive current is flowing through it. Close-grained wood — Wood with narrow and inconspicuous annual rings. The term is sometimes used to designate wood having small and closely spaced pores, but in this sense the term “fine-textured” is more often used. Coil shot — Production of longitudinal magnetization accomplished by passing current through a coil encircling the part being inspected. [AC 43.13-1B p. App 4] Appendix 1 Compass — A device used to determine direction on the Earth’s surface. A magnetic compass utilizes the Earth’s magnetic field to establish direction. Compression wood — Identified by its relatively wide annual rings, usually eccentric, and its relatively large amount of summer wood, usually more than 50 percent of the width of the annual rings in which it occurs. Compression wood shrinks excessively lengthwise as compared with normal wood. Conductor — A wire or other material suitable for conducting electricity. Conduit — A rigid metallic or nonmetallic casing, or a flexible metallic casing covered with a woven braid or synthetic rubber used to encase electrical cables. Contact — Electrical connectors in a switch, solenoid or relay that controls the flow of current. Control panel — An upright panel, open or closed, where switches, rheostats, meters, etc., are installed for the control and protection of electrical machinery. Corrosion — The electrochemical deterioration of a metal resulting from chemical reaction to the surrounding environment. Crack — Is a partial separation of material caused by vibration, overloading, internal stresses, nicks, defective assemblies, fatigue, or rapid changes in temperature. Creepage — Is the conducting of electrical current along a surface between two points at different potentials. The current’s ability to pass between two points increases with higher voltage and when deposits of moisture or other conductive materials exist on the surfaces. Cross grain — Grain not parallel with the axis of a piece. It may be either diagonal or spiral grain or a combination of the two. Cross coat — A double coat of dope or paint. It is sprayed on in one direction, and then immediately after the solvent flash-off, it is sprayed at right angles to the first coat. Cure — To change the properties of a thermosetting resin irreversibly by vulcanization or chemical reaction. May be accomplished by the addition of curing (cross-linking) agents, with or without a catalyst, and with or without heat or pressure. Curing temperature — Temperature to which a resin or an assembly is subjected in order to cure the resin. Cutting torch — A device used in gas cutting of metals. [AC 43.13-1B p. App 5] Appendix 1 -D- Damping — Limiting the duration of vibration by either electrical or mechanical means. Data — Information that supports and/or describes the original aircraft design, alteration or repair, including the following: (1) drawings, sketches, and or photographs; (2) engineering analysis; (3) engineering orders; and (4) operating limitations. Datum — Imaginary vertical plane from which all horizontal measurements are made or indicated when the aircraft is in level flight attitude. Derating — Is a technique whereby a part is stressed in actual usage at values well below the manufacturer’s rating for the part. By decreasing mechanical, thermal, and electrical stresses, the probability of degradation or catastrophic failure is lessened. Direct current electrode negative — The arrangement of direct current arc welding leads in which the work is the positive pole and the electrode is the negative pole of the welding arc. Direct current electrode positive — The arrangement of direct current arc welding leads in which the work is the negative pole and the electrode is the positive pole of the welding arc. Discontinuity — An interruption in the normal physical structure or configuration of a part, such as a crack, lap, seam, inclusion, or porosity. Distal tip — The tip, lens end, of a borescope. Dope — Liquid applied to fabric to tauten it by shrinking, strengthen it, and render it airtight by acting as a filler. Dope-proofing — Protecting a surface from the chemicals and chafing qualities of dope and doped fabrics. Drape — The ability of tape and broad goods to conform to a contoured shape. Drip loop — A bundle installation method used to prevent water or other fluid contaminants from running down the wiring into a connector. Dry rot — A term loosely applied to many types of wood decay but especially to that which, when in an advanced stage, permits the wood to be easily crushed to a dry powder. The term is actually a misnomer for any decay, since all fungi require considerable moisture for growth. Dwell time — The total time that a penetrant, emulsifier (or remover), or developer remains on the surface of the test part. Dye penetrant inspection — An inspection method for surface cracks in which a penetrating dye is allowed to enter any cracks present and is pulled out of the crack by an absorbent developer. A crack appears as a line on the surface of the developer. [AC 43.13-1B p. App 6] Appendix 1 -E- Edge grain — Edge-grain lumber has been sawed parallel with the pith of the log and approximately at right angles to the growth rings; that is, the rings form an angle of 45 degrees or more with the surface of the piece. Electricity — One of the fundamental quantities in nature consisting of elementary particles, electrons and protons, which are manifested as a force of attraction or repulsion, and also in work that can be performed when electrons are caused to move; a material agency which, when in motion, exhibits magnetic, chemical, and thermal effects, and when at rest is accompanied by an interplay of forces between associated localities in which it is present. Electromagnet — Temporary magnet which is magnetized by sending current through a coil of wire wound around an iron core. Electromagnetic Interference/Radio-Frequency Interference (EMI/RFI) — Frequency spectrum of electromagnetic radiation extending from subsonic frequency to X-rays. This term should not be used in place of the term radio-frequency interference (RFI). (See radio frequency interference.) Shielding materials for the entire EMI spectrum are not readily available. Electromotive force (EMF) — Difference of electrical potential measured in volts. Electron — A negative charge that revolves around the nucleus of an atom; a unit of a negative electrical charge. Electronics — General term that describes the branch of electrical science and technology that treats the behavior and effects of electron emission and transmission. Electron Volt (eV) — A unit of energy equal to the energy acquired by an electron falling though potential differences of one volt, approximately 1.602X 10-19 joule. Emulsion-type cleaner — A chemical cleaner which mixes with water or petroleum solvent to form an emulsion (a mixture which will separate if allowed to stand). It is used to loosen dirt, soot, or oxide films from the surface of an aircraft. Epoxy — One of various usually thermosetting resins capable of forming tight cross-linked polymer structures marked by toughness, strong adhesion, high corrosion, and chemical resistance, used especially in adhesives and surface coating. Epoxy primer — A two-part catalyzed material used to provide a good bond between a surface and a surface coating. Epoxy resin — A common thermosetting resin which exhibits exceptionally good adhesion, low cure shrinkage, and low water-absorption properties. Erosion — Loss of metal from metal surfaces by the action of small particles such as sand or water. [AC 43.13-1B p. App 7] Appendix 1 ETFE — Ethylene tetrafluoroethylene (frequently referred to by the trade name, TEFZEL), a copolymer of PTFE and polyethylene. Exciter — Small generator for supplying direct current to the alternator’s field windings. Exfoliation corrosion — A form of intergranular corrosion that attacks extruded metals along their layer-like grain structure. Expandable sleeving — Open-weave braided sleeving used to protect wire and cables from abrasion and other hazards (commonly known by trade name EXPANDO). -F- FEP — Fluorinated ethylene propylene (commonly known by the trade name, TEFLON). A melt extrudable fluorocarbon resin, very similar in appearance and performance to PTFE, but with a maximum temperature rating of 200 °C. Ferrous metal — Iron, or any alloy containing iron. Fiberglass —The most common material used to reinforce structures in home-built and experimental aircraft. Available as mat, roving, fabric, etc. It is incorporated into both thermoset and thermoplastic resins. The glass fibers increase mechanical strength, impact resistance, stiffness, and dimensional stability of the matrix. Fill — Threads in a fabric that run crosswise of the woven material. Filiform corrosion — A thread, or filament-like corrosion which forms on aluminum skins beneath the finish. Finish — External coating or covering of an aircraft or part. Flat grain — Lumber has been sawed parallel with the pith of the log and approximately tangent to the growth rings; that is, the rings form an angle of less than 45 degrees with the surface of the piece. Fluorescent — A substance is said to be fluorescent when it will glow or fluoresce when excited by ultraviolet light. Some types of dye-penetrant material use fluorescent dyes which are pulled from the cracks by a developer and observed under “black” ultraviolet light. Flux — Materials used to prevent, dissolve, or facilitate removal of oxides and other undesirable surface substances. Also, the name for magnetic fields. Fretting corrosion — Corrosion damage between close-fitting parts which are allowed to rub together. The rubbing prevents the formation of protective oxide films and allows the metals to corrode. Fuse — A protective device containing a special wire that melts when current exceeds the rated value for a definite period. [AC 43.13-1B p. App 8] Appendix 1 Functional check — This test may require the use of appropriate test equipment. -G- Galvanic corrosion — Corrosion due to the presence of dissimilar metals in contact with each other. Gas cylinder — A portable container used for transportation and storage of a compressed gas. Gas tungsten arc welding (GTAW) — An arc welding process which produces coalescence of metals by heating them with an arc between a tungsten (nonconsumable) electrode and the work. Shielding is obtained from a gas or gas mixture. Pressure may or may not be used and filler metal may or may not be used. Generator — A device for converting mechanical energy into electrical energy. Global positioning system (GPS) — A navigation system that employs satellite transmitted signals to determine the aircraft’s location. Grain — The direction, size, arrangement, appearance, or quality of the fibers in wood or metal. Grain-diagonal —Annual rings in wood at an angle with the axis of a piece as a result of sawing at an angle with the bark of the tree. Grommet — An insulating washer that protects the sides of holes through which wires must pass/or a metal or plastic drain attached to fabric on aircraft. Gross weight — The total weight of the aircraft including its contents. Grounding — The term is usually applied to a particular form of bonding that is the process of electrically connecting conductive objects to either conductive structure or some other conductive return path for the purpose of safely completing either a normal or fault circuit. -H through L- Harness — A cable harness is a group of cables or wires securely tied as a unit. Honeycomb — Manufactured product consisting of a resin-impregnated sheet or metal material which has been corrugated or expanded into hexagon-shaped and other structural-shaped cells. Primarily used as core material for sandwich constructions. Inductance (L) — The ability of a coil or conductor to oppose a change in current flow. Insulator — A material that will not conduct current to an appreciable degree. Integrated circuit — Small, complete circuit built up by vacuum deposition and other techniques, usually on a silicon chip, and mounted in a suitable package. [AC 43.13-1B p. App 9] Appendix 1 Intergranular corrosion — The formation of corrosion along the grain boundaries within a metal alloy. Interlocked-grained wood — Wood in which the fibers are inclined in one direction in a number of rings of annual growth, then gradually reverse and are inclined in an opposite direction in succeeding growth rings, then reverse again. Inverter — A device for converting direct current to alternating current. Laminate — A product obtained by bonding two or more laminae of the same material or of different materials. Laminated wood — A piece of wood built up of plies or laminations that have been joined either with glue or with mechanical fastenings. The term is most frequently applied where the plies are too thick to be classified as veneer and when the grain of all plies is parallel. Leakage field — The magnetic field forced out into the air by the distortion of the field within a part, caused by the presence of a discontinuity or change in section configuration. Linter — The short fiber left on the cotton seed after ginning. Localizer — That section of an ILS that produces the directional reference beam. LORAN (long-range navigation) — A radio navigation system utilizing master and slave stations transmitting timed pulses. The time difference in reception of pulses from several stations establishes a hyperbolic line of position that may be identified on a LORAN chart. By utilizing signals from two pairs of stations, a fix in position is obtained. -M through O- Magnetic field — The space around a source of magnetic flux in which the effects of magnetism can be determined. Marker beacon — A radio navigation aid used in an instrument approach to identify distance to the runway. As the aircraft crosses over the marker-beacon transmitter, the pilot receives an accurate indication of the airplane’s distance from the runway through the medium of a flashing light and an aural signal. Master switch — A switch designed to control all electric power to all circuits in a system. Moisture content of wood — Weight of the water contained in the wood usually expressed in percentage of the weight of the kiln-dry wood. Multiconductor cable — Consists of two or more cables or wires, all of which are encased in an outer covering composed of synthetic rubber, fabric, or other material. Nick — A sharp notch-like displacement of metal surface. [AC 43.13-1B p. App 10] Appendix 1 Nomex braid — NOMEX is the trade name for a high-temperature polyamide thread that is braided over the larger sizes (# 8 gage and larger) of many of the military specification wires. It can be encountered in either an off-white or black/green color. Normalizing — Reforming of the grain structure of a metal or alloy by proper heat treatment to relieve internal stresses. Open circuit — An incomplete or broken electrical circuit. Open-grained wood — Common classification of painters for woods with large pores, such as oak, ash, chestnut, and walnut. Also known as “coarse-textured.” Operational check — This is an operational test to determine whether a system or component is functioning properly in all aspects in conformance with minimum acceptable manufacture design specifications. Optical fiber — Any filament or fiber made of dielectric materials that guides light whether or not it is used to transmit signals. Orifice — Opening through which gas or air flows. It is usually the final opening controlled by a valve. Oxidizing — Combining oxygen with any other substance. For example, a metal is oxidized when the metal is burned, i.e., oxygen is combined with all the metal or parts of it. Oxidizing flame —An oxy-fuel gas flame having an oxidizing effect due to excess oxygen. Oxygen cutting — Cutting metal using the oxygen jet which is added to an oxygen-acetylene flame. Oxygen regulator — Manually-adjustable device used to reduce cylinder pressure to torch pressure and to keep the pressure constant. They are never to be used as fuel gas regulators. -P- Peel ply — A layer of resin-free material used to protect a laminate for later secondary bonding (sometimes referred to as a release film). Pickling — The treatment of a metal surface by an acid to remove surface corrosion. Pitch — Is the distance, in inches, that a propeller section will move forward in one revolution, or the distance a nut will advance in one revolution of the screw in a single thread. Pitch distribution — Is the gradual twist in the propeller blade from shank to tip. Pitted — Small irregular shaped cavities in the surface of the parent material usually caused by corrosion, chipping, or heavy electrical discharge. Pitting — The formation of pockets of corrosion products on the surface of a metal. [AC 43.13-1B p. App 11] Appendix 1 Plastic — An organic substance of large molecular weight which is solid in its finished state and, at some stage during its manufacture or its processing into a finished article, can be shaped by flow. Polyester braid — A plastic braiding thread, when used as the outer surface of a wire, provides a cloth-like appearance. Polyimide tape — A plastic film (commonly referred to by the trade name, KAPTON). The tape has a dark brown color, and is frequently coated with a polyimide varnish that has a very distinct mustard yellow color. At times, the spiral edge of the outermost tape is apparent under the varnish topcoat. It may be used for wire insulation. Total polyimide tape insulated wire constructions are inactive for new design on military aircraft and are subject to the procedures defined in FAA Advisory Circular (AC) 29-2, Certification of Normal Category Rotorcraft, Paragraph 29.1359, in civil aircraft. Polyimide varnish — A liquid form of polyimide that is applied to the outer surface of a wire through the process of repeated dipping through the varnish bath with subsequent heat curing. The successive layers rarely reach a total buildup of 1 mil. Polymerization — Basic processes for making large (high-polymer) molecules from small ones, normally without chemical change; can be by addition, condensation, rearrangement, or other methods. Porosity — Cavity-type discontinuities in metal formed by gas entrapment during solidification. Prepreg — A mat, a fabric, or covering impregnated with resin that is ready for lay up and curing. Propeller — Is a rotating airfoil that consists of two or more blades attached to a central hub which is mounted on the engine crankshaft. Protractor — Is a device for measuring angles. PTFE Tape (Insulation) — Polytetrafluoroethylene tape (commonly known by the trade name, TEFLON), wrapped around a conductor and then centered with heat, fusing the layers into a virtually homogeneous mass. It is used both as a primary insulation against the conductor, and as an outer layer or jacket over a shield. Maximum temperature rating is 260 °C. PVF2 Polyvinylidine Fluoride — A fluorocarbon plastic, that when used in aircraft wire, is invariably radiation cross-linked and employed as the outer layer. -R- Radar (radio detecting and ranging) — Radio equipment that utilizes reflected pulse signals to locate and determine the distance to any reflecting object within its range. Radome — A nonmetallic cover used to protect the antenna assembly of a radar system. [AC 43.13-1B p. App 12] Appendix 1 Rectifier — A device for converting alternating current to direct current. Reinforcing tape — A narrow woven cotton or polyester tape used over aircraft fabric to reinforce it at the stitching attachments. Relay — An electrically-operated remote-control switch. Resin — Vast profusion of natural and increasingly, synthetic materials used as adhesives, fillers, binders and for insulation. Resistance — The opposition a device or material offers to the flow or current. Resonance method (ringing) of ultrasonic inspection — A method of detecting material thickness or indications of internal damage by injecting variable frequency ultrasonic energy into a material. A specific frequency of energy will produce the clearest indication of damage in a given thickness of material. When the equipment is calibrated for a specific thickness, and this thickness changes, an aural or visual alert is given. Resonant frequency — The frequency of a source of vibration that is exactly the same as the natural vibration frequency of the structure. Resonate — A mechanical system is said to resonate when its natural vibration frequency is exactly the same as the frequency of the force applied. When an object resonates at a particular frequency, the amplitude in its vibration will increase immensely as that frequency is reached and will be less on either side of that frequency. Rib — Part of primary structure, whose purpose is to maintain profile of airfoil and support fabric or thin wood covering. -S- Sacrificial corrosion — A method of corrosion protection in which a surface is plated with a metal less noble than itself. Any corrosion will attack the plating rather than the base metal. Sandwich construction — A structural panel concept consisting in its simplest form of two relatively thin, parallel sheets (face sheets) of structural material bonded to and separated by a relatively thick, lightweight core. High strength-to-weight ratios are obtained with sandwiched materials. Scarf joint — A joint made by cutting away similar angular segments of two adherents and bonding the adherents with cut areas fitted together. Score — A surface tear or break on a surface that has a depth and length ranging between a scratch and a gouge. Scratch — A superficial small cut on a surface. [AC 43.13-1B p. App 13] Appendix 1 Semiconductor device — Any device based on either preferred conduction through a solid in one direction, as in rectifiers; or on a variation in conduction characteristics through a partially conductive material, as in a transistor. Severe wind and moisture problem (SWAMP) areas — Areas such as wheel wells, wing folds, and near wing flaps, and areas directly exposed to extended weather conditions are considered SWAMP areas on aircraft. Silicone rubber — A high temperature (200 °C) plastic insulation that has a substantial silicone content. Soldering—A group of welding processes that produces coalescence of materials by heating them to the soldering temperature and by using a filler metal having a liquidus not exceeding 450 °C (840 °F) and below the solidus of the base metals. The filler metal is distributed between the closely fitted surfaces of the joint by capillary action. Solenoid — A tubular coil for the production of a magnetic field; electromagnet with a core which is able to move in and out. Spar — Main spanwise structural member(s) of an aircraft wing or rotorcraft rotor. A wing may have one or two made into a single strong box to which secondary leading and trailing structures are added. Spiral grain — A type of growth in wood which the fibers take a spiral course about the bole of a tree instead of the normal vertical course. The spiral may extend right-handed or left-handed around the tree trunk. Stator — The part of an AC generator or motor which contains the stationary winding. Stress corrosion — Corrosion of the intergranular type that forms within metals subject to tensile stresses which tend to separate the grain boundaries. Surface tape — Pinked-edge strips of fabric doped over all seams, rib stitching, and edges of fabric covering (also called finishing tape). Switch — A device for opening or closing an electrical circuit. -T- Tape — A tape or a “narrow fabric” is loosely defined as a material that ranges in width from 1/4 inch to 12 inches. TCAS — Traffic alert and collision avoidance system. An airborne system that interrogates mode A, C, and S transponders in nearby aircraft and uses the replies to identify and display potential and predicted collision threats. Thermocouple — Device to convert heat energy into electrical energy. [AC 43.13-1B p. App 14] Appendix 1 Thermoplastic material — A material that can be repeatedly softened by an increase in the temperature and hardened by a decrease in the temperature with no accompanying chemical change. For example, a puddle of tar on the road in the summer during the heat of day: the tar is soft and fluid; however, when cooler in the evening, it becomes solid again. Thermoset material — A material which becomes substantially infusible and insoluble when cured by the application of heat or by chemical means. A material that will undergo, or has undergone, a chemical reaction (different from a thermoplastics physical reaction) by the action of heat, catalysts, ultraviolet light, etc. Once the plastic becomes hard, additional heat will not change it back into a liquid as would be the case with a thermoplastic. Tip — Part of the torch at the end where the gas burns, producing the high-temperature flame. Transceiver — A unit serving as both a receiver and a transmitter. Transformer — A device for raising or lowering AC voltage. Transmitter — An electronic system designed to produce modulated RF carrier waves to be radiated by an antenna; also, an electric device used to collect quantitative information at one point and send it to a remote indicator electrically. Transponder — An airborne receiver-transmitter designed to aid air traffic control personnel in tracking aircraft during flight. -U through X- Unbonding — Adhesive or cohesive failure between laminates. Compare definitions of adhesive, cohesive debond, and disbond. Very high frequency (VHF) — A frequency between 30 and 300 MHz. VHF omnirange (VOR) — An electronic air navigation system that provides accurate direction information in relation to a certain ground station. Videoscope — A type of borescope. Visible light — Electromagnetic radiation that has a wavelength in the range from about 3,900 to 7,700 angstroms and that may be seen by the unaided human eye. Visual check — Utilizing acceptable methods, techniques, and practices to determine physical condition and safety item. Volt — Unit of potential, potential difference, or electrical pressure. Voltage regulator — Device used in connection with generators to keep the voltage constant as load or speed is changed. Warp — Threads in a fabric that run the length of the woven material as it comes from the mill. [AC 43.13-1B p. App 15] Appendix 1 Watt — The unit of power; equal to a joule per second. Wattmeter — An instrument for measuring electrical power. Waveguide — A hollow, typically rectangular, metallic tube designed to carry electromagnetic energy at extremely high frequencies. Wavy-grained wood — Wood in which the fibers collectively take the form of waves or undulations. Welding — A materials-joining process used in making welds. Welding rod — A form of welding filler metal, normally packaged in straight lengths. Welding torch — The device used in gas welding. Wood decay — Disintegration of wood substance through the action of wood-destroying fungi. Wood decay – incipient — The early stage of decay in which the disintegration has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood. Wood decay – typical or advanced — The stage of decay in which the disintegration is readily recognized because the wood has become punky, soft and spongy, stringy, pitted, or crumbly. X-ray — A radiographic test method used to detect internal defects in a weld. XL-ETFE — A process of radiation cross-linking the polymer chains is used to thermally set the plastic. This prevents the material from softening and melting at elevated temperature. XL-Polyalkene — An insulation material based on the polyolefin family that has its normally thermomelt characteristic altered by the radiation cross-linking process to that of a nonmelt, therm-set material. [AC 43.13-1B p. App 1] Appendix 2 ## APPENDIX 2. ACRONYMS AND ABBREVIATIONS The acronyms and abbreviations listed are some of many that are likely to be encountered by the aviation mechanic or technician involved in the maintenance of aircraft. 429 — ARINC 429 data bus standard | ARNC IO — ARINC I/O Error 629 — ARINC 629 data bus standard | ARNC STP — ARNC I/O UART data strip error A/D — analog/digital; Analog-to-Digital | ASTM — ASTM International A/D CONV — Analog-to-Digital Converter | ATA — Air Transport Association A/L — autoland | ATC — air traffic control AC — advisory circular | ATCT — ATC transponder AC — alternating current | ATCTS — ATC transponder system ACARS — Aircraft Communications | AUX — auxiliary Addressing and Reporting System ACO — Aircraft Certification Office | AVC — automatic volume control AD — Airworthiness Directive | AWG — American Wire Gauge ADC — air-data computer | AWS — Automatic Weather Station ADCP — ATC dual-control panel | B/CU — battery/charger unit ADEDS — Advanced Electronic Display | BAT or BATT — battery System ADF — automatic direction finder | BCD — binary-coded decimal ADI — Attitude-Director Indicator; Air Data | BIT — binary digit; Built-in Test Instrument AFC — automatic frequency control | BITE — built-in test equipment AFCS — automatic flight control system | BITS — bus interconnect transfer switch AFDS — Autopilot Flight Director System | BNR — Binary Numerical Reference; binary AIM — Aeronautical Information Manual | BP — band-pass AIRCOM — Air/ground Communications | BPCU — bus power control unit AM — amplitude modulation | BT — bus tie amp — amperes | BTB — bus tie breaker AMP or AMPL — amplifier | BTC — before top center AMS — Aerospace Material Specification | BUS — electrical bus; 429 digital data bus AN — Army/Navy | C.G. — center of gravity AND — Army Navy Design | CAGE — commercial and government entity code ANSI — American National Standards | CAWS — central aural warning system; Institute | caution and warning system ANT — antenna | CB, C/B, or CKT/BKR — circuit breaker AP — autopilot | CDI — course-deviation indicator APB — auxiliary power breaker | CDU — central display unit APCU — auxiliary power control unit | CFC — carbon fiber composite APU — auxiliary power unit | CFDS — centralized fault display system ARINC — Aeronautical Radio, Inc. | CAC — caution advisory computer [AC 43.13-1B p. App 2] Appendix 2 CH or chan. — channel | DISC — disconnect CHGR — charger | DISTR — distribution CKT — circuit | DMA — direct memory access CLK — clock | DMB — dead main bus CLR — clear | DMC — display management computer CMCS — central maintenance computer | DME — distance measuring equipment system CMPTR — computer | DMEA — distance-measuring equipment antenna CO — carbon monoxide | DN — down COAX — coaxial | DU — display unit COP — copper | E/E or E & E — electrical/electronic CP — control panel | E1-1 — first shelf, number 1 equipment rack CRT — cathode ray tube; circuit | E2-2 — second shelf, number 2 equipment rack CSE or CSEU — control system electronics | EADF — electronic automatic direction unit | finder CSEUP — control system electronics unit | EADI — electronic attitude director indicator panel CT — Computed Tomography | EAROM — electrically alterable read-only memory CT — current transformer | EC — EICAS computer CTN — caution | ECAM — electronic centralized aircraft monitoring CU — control unit; copper | EDSP — EICAS display select panel CVR — cockpit voice recorder | EDU — EICAS display unit CW — continuous wave | EEC — electronic engine control D/A — digital-to-analog | EFI — electronic flight instrument DAC — digital-to-analog converter | EFIS — electronic flight instrument system DADC — digital air-data computer | EFISCP — EFIS Control Panel DBT — dead bus tie | EFISCU — EFIS comparator unit dc — direct current | EFISG EFIS — symbol generator DCDR — decoder | EFISRLS — EFIS remote light sensor DDB — digital data bus | EHSI — electronic horizontal-situation indicator DEMOD — demodulator | EHSID — electronic horizontal-situation indicator display DEMUX — demultiplexer | EHSV — electrohydraulic servo value DER – Designated Engineering | EICAS — engine indicating and crew Representative | alerting system DFDR — digital flight data recorder | ELCU — electrical load control unit DG — directional gyro | ELEC — electric; electronic DGTL — digital | ELECT — electrical DH — decision height | ELEX — electronics; electrical DISC SOL — disconnect solenoid | ELT — emergency locator transmitter [AC 43.13-1B p. App 3] Appendix 2 EMER GEN — emergency generator | GND or GRD — ground EMF — electromotive force | GPCU — ground power control unit EMFI — electromechanical flight instrument | GPS — Global Positioning System EMI — electromagnetic interference | GPSW — gear opposition switch EP — external power | GPU — ground power unit EP AVAIL — external power available | GPW — ground proximity warning EPC — external power contactor | GPWC — ground proximity warning computer EPCS — electronic power control switch | GPWS — ground proximity warning system EPROM — erasable programmable read- | GSR — ground service relay only memory eV — electron volt | GSSR — ground service select relay EXCTR — exciter | GSTR — ground service transfer relay EXT PWR — external power | GTAW — gas tungsten arc welding FAA — Federal Aviation Administration | H/L — high/low FAA-PMA — Federal Aviation | HEA — high-frequency radio antenna Administration Parts Manufacturer Approval FM — frequency modulation | HF (hf) — high frequency (3 to 30 MHz) FM/CW — frequency modulation continuous | HFCP — high-frequency radio control panel wave FMC — flight management computer | HI Z — high impedance FMCD — flight management computer | Hz — hertz control display unit FMCS — flight management computer | I.D. — inner diameter systems FMS — flight management system | I/O — input/output FOD — foreign object damage | IAPS — integrated avionics processor system FREQ — frequency | IAS — indicated airspeed FSEU — flap/slat electronic unit | IDG — integrated drive generator FW or FWD — forward | IF — intermediate frequency G/S — glide slope | IFR — instrument flight rules GAL or GALY — galley | IGN — ignition GCR — generator control relay auxiliary | IIS — integrated instrument system contact GCU — generator control unit | ILS — instrument landing system GEB — generator circuit breaker | INDL — indicator light GEN — generator | INST — instrument GLR — galley load relay | INSTR — instrument GMAW — Gas Metal Arc Welding | INTCON — interconnect GMT — Greenwich mean time; coordinated | INTEC — interface Universal time GND PWR — ground power | INTER — interrogation GND RET — ground return | INTPH — interphone GND SVCE — ground service | INV — inverter [AC 43.13-1B p. App 4] Appendix 2 IR — ILS receiver | MILLI — one-thousandth (0.001) kHz — kilohertz | MKR BCN — marker beacon KSI — thousands of pounds per square inch | MS — Military Standard kV — kilovolts | MSDS — Material Safety Data Sheets kVA — kilovolt-amperes | MSEC — (ms) milliseconds kVAR — kilovoltampere reactive | MSG — message L-Band — radio frequency band (390 to | MTBF — mean time between failure 1550 MHz) LCD — liquid crystal display | MUX — multiplexer LD — load | mV — millivolts LED — light-emitting diode | NAS — National Aerospace Standard lf — low frequency (30 to 300 kHz) | NAV — navigation LOZ — low impedance | NC — normally closed; not connected; no connection LOC — Localizer | NDB — nondirectional beacon LOX – liquid oxygen | NDI — Nondestructive Inspection LRU — line replaceable unit | NEG — negative LS — loudspeaker | nsec (ns) — nanoseconds LSB — lower sideband | NTSB — National Transportation Safety Board LSPTM — limit switch position transmitter | NVM — nonvolatile memory module LT — light | OAM — original aircraft manufacturer LTS — lights | OBS — omni bearing selection MAC — mean aerodynamic chord | OC — over-current MAN/ELEC — manual/electric | OEM — Original Equipment Manufacturer MBA — marker-beacon antenna | OF — over-frequency MCDP — maintenance control and display | OVV or OV — overvoltage panel MCDU — multipurpose control and display | OVVCO or OVCO — overvoltage cutout unit MDE — modern digital electronics | P-S — parallel to series MEC — main equipment center; main engine | PA — passenger address; power amplifier control meg or mega — million | PARA/SER — parallel to serial MEK — methylethylketone | PCU — passenger control unit; power control unit MEM — memory | PMA — Parts Manufacturer Approval METO — maximum except-takeoff | PMG — permanent-magnet generator MF — (mf) medium frequency (300 kHz to | POS — positive 3 MHz) MHz — megahertz | POT — potentiometer; plan of test MIC — microphone | PR — power relay MICRO-P — microprocessor | PRL — parallel MIG — Metal Inert Gas | PROM — programmable read-only memory [AC 43.13-1B p. App 5] Appendix 2 PROX — proximity | SOT — start of transmission PSEU — proximity switch electronic unit | SPKR — speaker psi — pounds per square inch | SPR — software problem report PWR — power | SQL — squelch PWR SPLY — power supply | SRM – Structural Repair Manual QPL — Qualified Products List | SSB — single sideband QTY — quantity | SSID — Supplemental Structural Inspection Documents r-t — receiver-transmitter | SSM — sign status matrix RA — radio altimeter; radio altitude | ST — synchro transmitter RAD — radio | STAT INV — static inverter RAIND — radio altimeter indicator | STBY — standby RAM — Random-Access Memory | STC — Supplemental Type Certificate RART — radio altimeter receiver-transmitter | SW — switch RAT — ram air turbine | SYM GEN — symbol generator RCCB — remote-control circuit breaker | T-R — transformer-rectifier RCL — recall | TAT — true air temperature RCVR — receiver | TBDP — tie bus differential protection RCVR/XMTR — receiver/transmitter | TC — type certificate RDMI — radio distance magnetic indicator | TCAS — Traffic Alert and Collision Avoidance System RF (rf) — radio frequency | TCDS — Type Certificate Data Sheet RFI — radio-frequency interference | TDC — top dead center RLS — remote light sensor | TFR — transfer RMI — radio magnetic indicator | TIG — tungsten inert gas rpm — revolutions per minute | TMC — thrust management computer RTV — room temperature vulcanizing | TMS — Terminal Marking Sleeve SAE — SAE International | TMS — thrust management system SAT — static air temperature | TMSP — thrust mode select panel SATCOM — satellite communications | TRU — transformer-rectifier unit SCR — silicon-controlled rectifier | TSO — Technical Standard Order SDI — source destination identifier | TXPDR — transponder SELCAL — selective calling system | µ — micro SER DL — serial data link | UBR — utility bus relay SG — symbol generator | UF — under-frequency SITA — Societe International de | UHF — ultrahigh frequency (300 MHz to Télécommunications Aeronautiques | 3 GHz) SMAW — Shielded Metal Arc Welding | UNDF — under-frequency SMD — surface mounted device | UNDV — under-voltage SNR — signal-to-noise ratio | US — under-speed SOL — solenoid | USB (us) — upper sideband SOLV — solenoid valve | µsec — microseconds SOM — start of message | UV — ultraviolet [AC 43.13-1B p. App 6] Appendix 2 UV — Under Voltage | WARN — warning V ac, Vac, or VAC — volts alternating | WCP — weather radar control panel current V dc, Vdc, or VDC — volts direct current | WEA — weather V — volts; voltage; vertical; valve | WEU — warning electronics unit power supply VA — volt-ampere | WPT — waypoint VAR — volt-ampere reactive | WX (WXR) — weather radar VFR — visual flight rules | XCVR — transceiver VHF (vhf) — very high frequency (30 to | XDCR — transducer 300 MHz) VLSI — very large-scale integration | XFMR — transformer VOR — VHF omni-directional range | XFR — transfer VORTAC — VOR Tactical Air Navigation | XMIT — transmit VR — voltage regulator | XMTR — transmitter VRMS — volts root means square | XPDR — transponder W — watts [AC 43.13-1B p. App 1] Appendix 3 ## APPENDIX 3. METRIC-BASED PREFIXES AND POWERS OF 10 Atto (a) | = | quintillionth of | = | 10-18 times Femto (f) | = | quadrillionth of | = | 10-15 times Pico (p), or (µµ) | = | trillionth of | = | 10-12 times Nano (n), or (mµ) | = | billionth of | = | 10-9 times Micro (µ) | = | millionth of | = | 10-6 times Milli (m) | = | thousandth of | = | 10-3 times Centi (c) | = | hundredth of | = | 10-2 times Deci (d) | = | tenth of | = | 10-1 times unity | = | 100 = 1 Deka (da) | = | ten times | = | 10 times Hecto (h) | = | hundred times | = | 102 times Kilo (k) | = | thousand times | = | 103 times Mega (M) | = | million times | = | 106 times Giga (G), or (kM) | = | billion times | = | 109 times Tera (T) | = | trillion times | = | 1012 times