AC 43.13-1B

Appendix 1

621 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 prev ents 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.

functional checkthis test may require the use of appropriate test equipment.

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 conduc tive objects to either conductive structure or some other conductive return path for the purpose of safely completing either a normal or fault circuit.

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.

Appendix 1

622 integrated circuitsmall, complete circuit built up by vacuum deposition and other techniques, usually on a silicon chip, and mounted in a suitable package.

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.

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.

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 iden tify 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.

nomex braidNOMEX is the trade name for a hightemperature 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 offwhite 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 “coarsetextured.”

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.

Appendix 1

623 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.

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.

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 29-2A Change 2 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.

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.

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.

Appendix 1

624 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 exactl y 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.

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-toweight 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.

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 closelyfitted 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 stit ching, and edges of fabric covering (also called finishing tape).

switcha device for opening or closing an electrical circuit.

Appendix 1

625 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 sy stem 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.

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, ultr aviolet 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.

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.

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.

Appendix 1

626 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.

Appendix 2

1 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 629ARINC 629 data bus standard A/Danalog/digital; analog-to -digital A/D CONVanalog-to -digital converter A/Lautoland ACAdvisory Circular acalternating current ACARSARINC Communication Addressing and Reporting System ACOAircraft Certification Office ADAirworthiness Directive ADCair-data computer ADCPATC dual-control panel ADEDSadvanced electronic display system ADFautomatic direction finder ADIattitude-director indicator; air data instrument AFCautomatic frequency control AFCSautomatic flight control system AFDSautopilot flight detector system AIMAeronautical Information Manual AIRCOMair/ground communications AMamplitude modulation AMP or AMPLamplifier AMPamperes AMSAerospace Material Specification ANArmy/Navy ANDArmy Navy Design ANSIAmerican National Standards Institute ANTantenna APautopilot APBauxiliary power breaker APCUauxiliary power control unit APUauxiliary power unit ARINCAeronautical Radio Incorporated ARNC IOARINC I/O error ARNC STPARINC I/O UART data strip error ASTMAmerican Society for Testing Materials ATAAir Transport Association ATCair traffic control ATCTATC transponder ATCTSATC transponder system AUXauxiliary AVCautomatic volume control AWGAmerican Wire Gauge AWSAir Weather Service B/CUbattery/charger unit BAT or BATTbattery BCDbinary-coded decimal BITbinary digit; built-in test BITEbuilt-in test equipment BITSbus interconnect transfer switch BNRbinary numerical reference; binary BPband-pass BPCUbus power control unit BTbus tie BTBbus tie breaker BTCbefore top center BUSelectrical bus; 429 digital data bus C.G.Center of Gravity CACcaution advisory computer CAGEcommercial and government entity code CAWScentral aural warning system; caution and warning system CB, C/B, or CKT/BKRcircuit breaker CDIcourse-deviation indicator CDUcentral display unit CFCcarbon fiber composite CFDIUcentralized fault display interface unit CFDScentralized fault display system CH or CHANchannel CHGRcharger CKTcircuit CLKclock CLRclear CMCScentral maintenance computer system CMPTRcomputer COcarbon monoxide COAXcoaxial COPcopper CPcontrol panel CRTcathode-ray tube; circuit CSE or CSEU control system electronics unit CSEUPcontrol system electronics unit panel CTcomputed tomography CTcurrent transformer CTNcaution CUcontrol unit; copper CVRcockpit voice recorder CWcontinuous wave D/Adigital-to-analog DACdigital-to analog converter DADCdigital air-data computer DBTdead bus tie dcdirect current

Appendix 2

2 DCDRdecoder DDBdigital data bus DEMODdemodulator DEMUXdemultiplexer DFDRdigital flight data recorder DGdirectional gyro DGTLdigital DHdecision height DISC SOLdisconnect solenoid DISCdisconnect DISTRdistribution DMAdirect memory access DMBdead main bus DMCdisplay management computer DMEdistance-measuring equipment DMEAdistance-measuring equipment antenna DNdown DUdisplay unit E/Eor E & E electrical/electronic E1-1first shelf, number 1 equipment rack E2-2second shelf, number 2 equipment rack EADFelectronic automatic direction finder EADIelectronic attitude-director indicator EAROMelectrically alterable read-only memory ECEICAS computer ECAMelectronic centralized aircraft monitoring EDSPEICAS display select panel EDUEICAS display unit EECelectronic engine control EFIelectronic flight instrument EFISelectronic flight instrument system EFISCPEFIS control panel EFISCUEFIS comparator unit EFISG EFISsymbol generator EFISRLS EFISremote light sensor EHSIelectronic horizontal-situation indicator EHSIDelectronic horizontal-situation indicator display EHSVelectrohydraulic servo value EICASengine indicating and crew alerting system ELCUelectrical load control unit ELECelectric; electronic ELECTelectrical ELEXelectronics; electrical ELTEmergency Locator Transmitter EMER GENemergency generator emfelectromotive force EMFIelectromechanical flight instrument EMIElectromagnetic interference EP AVAILexternal power available EPexternal power EPCexternal power contactor EPCSelectronic power control switch EPROMerasable programmable read-only memory eV—electron volt EXCTRexciter EXT PWRexternal power FAAFederal Aviation Administration FAA-PMAFederal Aviation Administration Parts Manufacturer Approval FMfrequency modulation FM/CWfrequency modulation continuous wave FMCflight management computer FMCDflight management computer control display unit FMCSflight management computer system FMSflight management system FODforeign object damage FREQfrequency FSEUflap/slat electronic unit FW or FWDforward G/Sglide slope GAL or GALYgalley GCRgenerator control relay auxiliary contact GCUgenerator control unit GEBgenerator circuit breaker GENgenerator GLRgalley load relay GMAWgas metal arc welding GMTGreenwich mean time; cordinated Universal time GND PWRground power GND RETground return GND SVCEground service GND or GRDground GPCUground power control unit GPSglobal positioning system GPSWgear opposition switch GPUground power unit GPWground proximity warning GPWSground proximity warning system GSRground service relay GSSRground service select relay GSTRground service transfer relay GTAWgas tungsten arc welding GWPCground proximity warning computer H/Lhigh/low HEAhigh-frequency radio antenna HF (hf) high frequency (3 to 30 MHz) HFCPhigh-frequency radio control panel HI Zhigh impedance HZhertz

Appendix 2

3 I.D.inner diameter I/Oinput/output IAPSintegrated avionics processor system IASindicated airspeed IDGintegrated drive generator IFintermediate frequency IFRinstrument flight rules IGNignition IISintegrated instrument system ILSinstrument landing system INDLindicator light INSTinstrument INSTRinstrument INTCONinterconnect INTECinterface INTERinterrogation INTPHinterphone INVinverter IR ILSreceiver kHzkilohertz KSIthousands of pounds per square inch kVkilovolts kVAkilovoltamperes kVARkilovoltampere reactive L-Bandradio frequency band (390 to 1550 MHz) LCDliquid-crystal display LDload LEDlight-emitting diode LF (lf) low frequency (30 to 300 kHz) LO Zlow impedance LOClocalizer LRUline replaceable unit LSloudspeaker LSBlower sideband LSPTMlimit switch position transmitter module LTlight LTS lights MACmean aerodynamic chord MAN/ELECmanual/electric MBAmarker-beacon antenna MCDPmaintenance control and display panel MCDUmultipurpose control and display unit MDEmodern digital electronics MECmain equipment center; main engine control MEG or MEGAmillion MEKmethylethylketone MEMmemory METOMaximum except-take off MF(mf) medium frequency (300 kHz to 3 MHz) MHzmegahertz MICmicrophone MICRO-Pmicroprocessor MIGmetal inert gas MILLIone one-thousandth (0.001) MKR BCNmarker beacon MSmilitary standard MSDSMaterial Safety Data Sheets MSEC(ms) milliseconds MSGmessage MTBFmean time-between-failure MUXmultiplexer mVmillivolts NASNational Aerospace Standard NAVnavigation NCnormally closed; not connected;

no connection NDBnondirectional beacon NDINondestructive Inspection NEGnegative NSEC (ns) nanoseconds NTSBNational Transportation Safety Board NVMnonvolatile memory OAMoriginal aircraft manufacturer OBSomni bearing selection OCovercurrent OEMoriginal equipment manufacturer OFover-frequency OVV or OVovervoltage OVVCO or OVCOovervoltage cutout P-Sparallel to series PApassenger address; power amplifier PARA/SERparallel to serial PCUpassenger control unit; power control unit PFDpermanent-magnet generator PMAParts Manufacturer Approval POSpositive POTpotentiometer; plan of test PRpower relay PRLparallel PROMprogrammable read-only memory PROXproximity PSEUproximity switch electronic unit PSIpounds per square inch PWRpower PWR SPLYpower supply QPLQualified Products List QTYquantity r-treceiver-transmitter RAradio altimeter; radio altitude RADradio RAIND radio altimeter indicator RAMrandom-access memory RARTradio altimeter receiver-transmitter

Appendix 2

4 RATram air turbine RCCBremote-control circuit breaker RCLrecall RCVRreceiver RCVR/XMTRreceiver/transmitter RDMIradio distance magnetic indicator RF (rf) radio frequency RFIradio-frequency interference RLSremote light sensor RMIradio magnetic indicator rpmrevolution per minute RTVroom temperature vulcanizing SAESociety of Automotive Engineers SATstatic air temperature SATCOMsatellite communication SCRsilicon-controlled rectifier SDIsource destination identifier SELCALselective calling system SER DLserial data link SGsymbol generator SITASociété International de Telecommunications Aeronautiques SMAWshielded metal arc welding SMDsurface mounted device SNRsignal-to-noise ratio SOLsolenoid SOLVsolenoid valve SOMstart of message SOTstart of transmission SPKRspeaker SPRsoftware problem report SQLsquelch SSBsingle sideband SSIDSupplemental Structural Inspection Documents SSMsign status matrix STsynchro transmitter STAT INVstatic inverter STBYstandby STCSupplemental Type Certificate SWswitch SYM GENsymbol generator T-Rtransformer-rectifier TATtrue air temperature TBDPtie bus differential protection TCType Certificate TCAStraffic alert and collision avoidance system TCDSType Certificate Data Sheets TDCtop dead center TFRtransfer TIGtungsten inert gas TMCthrust management computer TMSterminal marking sleeve TMSthrust management system TMSPthrust mode select panel TRUtransformer-rectifier unit TSOTechnical Standard Order TXPDRtransponder µmicro UBRutility bus relay UFunderfrequency UHFultrahigh frequency (300 MHz to 3 GHz) UNDFunderfrequency UNDVundervoltage USunderspeed USB (us)upper sideband USECmicroseconds UVundervoltage UVutraviolet V ac, Vac, or VACvolts alternating current V dc, Vdc, or VDC volts direct current Vvolts; voltage; vertical; valve VAvolt-amperes VARvolt-ampere reactive VFRvisual flight rules VHF (vhf) very high frequency (30 TO 300 MHz) VLSIvery large-scale integration VORVHF omnirange; visual omnirange VORTACVOR tactical air navigation VRvoltage regulator VRMSvolts root means square Wwatts WARNwarning WCPweather radar control panel WEAweather WEUwarning electronics unit power supply WPTwaypoint WX (WXR)weather radar XCVRtransceiver XDCRtransducer XFMRtransformer XFRtransfer XMITtransmit XMTRtransmitter XPDRtransponder

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 = 10 0 = 1 Deka (da) = ten times = 10 times Hecto (h) = hundred times = 10 2 times Kilo (k) = thousand times = 10 3 times Mega (M) = million times = 10 6 times Giga (G), or kM = billion times = 10 9 times Tera (T) = trillion times = 10 12 times

Appendix 3