航空电子缩列语词典AVIONICS GLOSSARY

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航空电子缩列语词典AVIONICS GLOSSARY

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A . . . . . . . . . . . . 2
B . . . . . . . . . . . . 13
C . . . . . . . . . . . . 16
D . . . . . . . . . . . . 24
E . . . . . . . . . . . . 31
F . . . . . . . . . . . . 37
G . . . . . . . . . . . .42
H . . . . . . . . . . . .45
I . . . . . . . . . . . .48
J . . . . . . . . . . . .53
K . . . . . . . . . . . .54
L . . . . . . . . . . .54
M . . . . . . . . . . .58
N . . . . . . . . . . . 65
O . . . . . . . . . . . 69
P . . . . . . . . . . . 72
Q . . . . . . . . . . . 80
R . . . . . . . . . . . 80
S . . . . . . . . . . .86
T . . . . . . . . . . .96
U . . . . . . . . . . . 104
V . . . . . . . . . . . 105
W . . . . . . . . . .109
X . . . . . . . . . . .111
Y . . . . . . . . . . . 112
Z . . . . . . . . . . . 112
*Av i o n ics-ese. Sometimes called Av - s p e a k .
I t ’s a confusing, sometimes frustrating language.
T h a t ’s why your friends at Rockwell Collins created this handy
compendium of acronyms, terms and definitions.
We hope it helps.
Copyright © 2001 Rockwell Collins, Inc.
w w w. ro c k w e l l c o l l i n s . c o m
C O N T E N T S O F G L O S S A R Y
AVIONICS GLOSSARY
How to Speak Avionics-ese*
3
A c c l r m Acce lerome ter
AC C T S Avia t ion Coordi n a t i ng Com m i t tee for
Te lec om mun ic a t ions Services
AC E ( 1 ) The con trol ch a racter mea n i ng tech n ical
ackn owledge
( 2 ) Act u a tor Con trol Electron ic s
( 3 ) Adva nced Cert i fic a t ion Equi pme n t
AC F Area Con trol Fac i l i ty
AC I D Ai rc raft Id e n t i fic a t ion
AC I P S Ai rfoil and Cowl Ice Pro tect ion Syste m
AC K The con trol ch a racter mea n i ng tech n ical
ackn owledge ment of an upl i nk, used in an ACA RS
syste m
AC M P A l tern a t i ng Current Mo tor Pum p
AC M S Ai rc raft Con di t ion Mon i tori ng Syste m
AC P Au dio Con trol Panel
AC S ( 1 ) Act ive Con trol Syste m
( 2 ) Au dio Con trol Syste m
AC S G Aeron au t ical Com mun ic a t ions Sub-Gro u p
AC T Act ive
AC U ( 1 ) A pron Con trol Un i t
( 2 ) An tenna Con trol Un i t
( 3 ) Au to pi lot Con trol Un i t
A / D An a log - To - D igi ta l
A D Adm i n i stra t ive Dom a i n
A DA C om p u ter Progra m m i ng Langu age
A DA S Au tom a ted Wea th er Observi ng System Da ta
Acqui s i t ion Syste m
A D C Air Da ta Com p u ter
A D F Au tom a t ic Direct ion Fi n d er
A D I Attitude Director In dic a tor
3 - D, 4-D T h ree or four di me n s ion
4096 Code The octal ba se, fo u r- digit code used be tween fra m i ng
p ul ses of a re ply to id e n t i fy the airc raft or for ge n era l
use and emerge ncy cod es (XPD )
1 0 B a s e T 10 Mbps ba se band data tra n s m i ss ion over twi sted
c o p per wi re
A ( 1 ) Au to t un ed NAVAID
( 2 ) Am peres
A AC Aeron au t ical Adm i n i stra t ive Com mun ic a t ion s
A A D Ass ign ed Altitude Devia t ion
A A I Ai rline Avion ics In st i t u te
A A L Above Aerod ome Leve l
A A M P Adva nced Arch i tect u re Mic ro - P rocessor
A AT S Avia t ion and Air Traffic Services
A AT T Adva nced Avia t ion Tra n s porta t ion Tech n ology
A / B Au to brake
A B E A R INC 429 Bus Emula tor
A B M Asynch ron o us Ba la nced Mod e
A- B P S K ( 1 ) Aeron au t ical Bi n a ry Phase Shift Keyi ng
( 2 ) Avia t ion Bi n a ry Phase Shift Keyi ng
A B R V Ab brevia t ion
A B S Absol u te
AC ( 1 ) Advi sory Circula r
( 2 ) A l tern a t i ng Curre n t
A / C Ai rc raft
AC A Ad dress Com press ion A lgori thm
AC AC Ai r- C ooled Air Cooler
AC A S Ai r borne Col l i s ion Avoid a nce Syste m
AC A R S Ai rc raft Com mun ic a t ions Ad dress i ng and
Re port i ng Syste m
AC C ( 1 ) Act ive Clea ra nce Con trol
( 2 ) Area Con trol Center
2
5
A F Ai rway Fac i l i t ies
A F C ( 1 ) Au tom a t ic Freque ncy Com pe n sa t ion
( 2 ) Au tom a t ic Freque ncy Con trol
A F C A S Au tom a t ic Fl ight Con trol Augme n ta t ion Syste m
A F C S Au tom a t ic Fl ight Con trol Syste m
A F D ( 1 ) Ad a p t ive Fl ight Display
( 2 ) Adva nced Fl ight Deck
( 3 ) Au to pi lot Fl ight Director
A F D C Au to pi lot Fl ight Director Com p u ter
A F D S Au to pi lot Fl ight Director Syste m
A F E P S ACA RS Front End Process i ng Syste m
A F I Au th ori ty Format Id e n t i fier
A F I S ( 1 ) Ai r borne Fl ight Inform a t ion Syste m
( 2 ) Au tom a t ic Fl ight Inform a t ion Service
A F M Ai rc raft Fl ight Ma nu a l
A F N ATS Fac i l i t ies No t i fic a t ion
A F S ( 1 ) Aeron au t ical Fi xed Service
( 2 ) Ai r borne Fi le Server
( 3 ) Au tom a t ic Fl ight Syste m
A F S S Au tom a t ic Fl ight Service Sta t ion
A F S K Au dio Freque ncy Shift Keyi ng
A F T N Aeron au t ical Fi xed Te lec om mun ic a t ion s
A F T R C C Aeros pace and Fl ight Text Radio Coordi n a t i ng
C o unc i l
A / G Ai r / G ro un d
AG AC S Au tom a t ic Gro un d - Air Com mun ic a t ion Syste m .
It is also kn own as ATC SS or DATA LIN K.
AG AT E Adva nced Ge n eral Avia t ion Tra n s port Experi me n t
AG C Au tom a t ic Gain Con trol . AGC is used to maintain
the output level of the rece iver.
AG I S Air Gro und In termedia te Syste m
A D I R S Air Da ta In ert ial Refere nce Syste m
A D I R U Air Da ta In ert ial Refere nce Un i t
A D L Aeron au t ical Da ta Link
A DLP ( 1 ) Ai r borne Da ta Link Pro toc ol
( 2 ) Ai rc raft Da ta Link Processor
A D L S Aeron au t ical Da ta Link Services
A D M Air Da ta Module
A D M S Ai rline Da ta Ma n age ment Syste m
A D P Air Da ta Processor
A D R A S Ai rplane Da ta Rec overy and An a lysis Syste m
A D S ( 1 ) Air Da ta Syste m
( 2 ) Au tom a t ic De pendent Surve i l la nce
A D S-A Au tom a t ic De pendent Surve i l la nce – Ad dress
A D S- B Au tom a t ic De pendent Surve i l la nce – Broa d c a st
A D S E L Ad dress Se lect ive. A SSR system electron ic a l ly
a rra nged to address each tra n s pon d er se lect ive ly.
O nly a pa rt icular tra n s pon d er will res pon d, th us
avoidi ng ga r bl i ng. A DSE L uses a mon o p ul se tech n ique
to provide more accu ra te bea ri ng mea s u re me n t .
A DSE L is com pa t i ble wi th DA BS. ( Refer to Mode S
tra n s pon d er s.)
A D S P Au tom a t ic De pendent Surve i l la nce Pa n e l
A D S U ( 1 ) Au tom a t ic De pendent Surve i l la nce Syste m
( 2 ) Au tom a t ic De pendent Surve i l la nce Un i t
A D T N Adm i n i stra t ive Da ta Tra n s m i ss ion Ne twor k
A E C U Au dio Electron ic Con trol Un i t
A E E C Ai rl i n es Electron ic Engi n eeri ng Com m i t tee
A E P ( 1 ) Au dio En terta i nment Player
( 2 ) Au to pi lot Engage Pa n e l
A E R A Au tom a ted En Ro u te traffic con trol
A E S Ai rc raft Earth Sta t ion
A E U Auxi l ia ry Equi pment Un i t
4
7
A I T Adva nced In te l l ige nce Ta pe - used for the storage of
digi tal vid eo and au dio fi les
A I V Accumula tor Isola t ion Va lve
A I X Adva nced In teract ive Execu t ive
A J P S AFE PS Jo u rnal Process i ng Syste m
A / L Au tola n d
A L C Au tom a t ic Level Con trol . A c i rcuit used to maintain
the output of a tra n s m i t ter rega rdless of va ria t ions in
the atte nu a t ion of the syste m .
A L E Au tom a t ic Link Esta bl i s hme n t
A L I A l t i me ter
A L PA Ai rline Pilo ts Assoc ia t ion
A L S A p pl ic a t ion Layer Struct u re
A L S I P C lea r
A LT ( 1 ) Ai r borne Link Term i n a l
( 2 ) A l tern a te
( 3 ) A l t i me ter
( 4 ) A l t i t u d e
A LT HOLD Altitude Hold Mod e
A l t i t u d e He ight determ i n ed by ba rome tric press u re
Altitude A c on t i nu o us re t u rn ac ross the di s play at a ra nge
R i n g equiva lent to airc raft altitude (WXR)
A LT S Altitude Se lect
A L U Ari thme t ic and Logic Un i t
A M Am plitude Modula t ion . A s ignal wh ere the carrier
s ignal is va ried in amplitude to enc ode voice or
d a ta inform a t ion .
A M A S S Ai rport Move ment Area Safe ty Syste m
A M C Avion ics Ma i n te n a nce Confere nce
A M C P Aeron au t ical Mo bi le Com mun ic a t ions Pa n e l
A M E Am plitude Modula t ion Equiva le n t . An AM type sign a l
that processes the modula ted inform a t ion signal and
c a rrier freque ncy se pa ra te ly and then rec on structs
the two signals to make an equiva lent AM sign a l .
AG L Above Gro und Leve l
AG R Ai r / G ro und Ro u ter
AG R M Ai r / G ro und Ro u ter Regional Ma n ager
AG R M S Ai r / G ro und Ro u ter Ma n age ment Syste m
AG S Ai r / G ro und Syste m
AG S S ACA RS Gro und System Sta n d a rd (AEEC )
AGT S Ai r / G ro und Test Sta t ion
A H C Attitude Hea di ng Com p u ter
A H R S Attitude Hea di ng Refere nce Syste m
A I ( 1 ) A l tern a t ive In terroga tor
( 2 ) Art i fic ial In te l l ige nce
A I C Aeron au t ical Inform a t ion Circula r
A I D A l tered Item Drawi ng. A drawi ng that details wh a t
a l tera t ion or ch a nge is made to an alrea dy exi st i ng
c om pon e n t .E xa m ples may be shorte n i ng the shaft
of a va ria ble res i stor, or addi ng a program to a circui t
c a rd to produce a progra m med circuit card.
A I D C Air Traffic Services (ATS) In ter- Fac i l i ty Da ta
C om mun ic a t ion s
A I D S Ai rc raft In tegra ted Da ta Syste m
A I E M Ai rl i n es In tern a t ional Electron ics Mee t i ng
A I M S Ai rc raft Inform a t ion Ma n age ment Syste m
A I N S C Aeron au t ical In dustry Service Com mun ic a t ion s
A I P Aeron au t ical Inform a t ion Publ ic a t ion
A I R AC Aeron au t ical Inform a t ion Regula t ion and Con trol
A I R C O M D igi tal air/gro und com mun ic a t ions services provid ed
by SITA . A system similar to ACA RS.
AIR DATA T h ose pa ra me ters that can be derived from
kn owledge of the air mass surro un di ng the airc raft .
A I R M E T Ai rm a n’s Me teorological (Inform a t ion )
A i r w a y s The sta n d a rd ICAO IFR ro u tes
A I S Aeron au t ical Inform a t ion Services
6
9
AO D C Age Of Da ta , C lock (GPS term )
AO D E Age Of Da ta , E p h e meris (GPS term )
AO G Ai rc raft On Gro un d
AO H E Air/Oil Heat Exch a nger
AO M Ai rc raft Opera t i ng Ma nu a l
AO P ( 1 ) Aeron au t ical OSI Profi le
( 2 ) Ai rline Opera t ional Procedu re
AO PA Ai rc raft Own ers and Pilo ts Assoc ia t ion
AO P G Aerodrome Opera t ions Gro u p
AO R Atla n t ic Ocean Region
AO R- E Atla n t ic Ocean Region - E a st
AO R-W Atla n t ic Ocean Region -West
A / P Au to pi lo t . A c om p u ter com m a n d ed system for
c on trol l i ng airc raft con trol surfaces.
A P Ai rport Loc a t ion (ACA RS / AFERS )
A PA ( 1 ) A l l ied Pilo ts Assoc ia t ion
( 2 ) Au to pi lot Am pl i fier
A P B Auxi l ia ry Power Breaker
A P C ( 1 ) Au to pi lot Com p u ter
( 2 ) Aeron au t ical Publ ic Corres pon d e nce
( 3 ) Aeron au t ical Pa sse nger Com mun ic a t ion
A P I A p pl ic a t ion Progra m m i ng In terface
A P M S Au tom a ted Perform a nce Mea s u re ment Syste m
A P N A R INC Packet Ne twor k
A P P ( 1 ) A p proach Con trol
( 2 ) Au to pi lot Pa n e l
A P P R A p proach
A P R Actual Perform a nce Reserve
A P R L ATN Profi le Requi re ment List
A P S Au to pi lot Syste m
A P U Auxi l ia ry Power Un i t
A M I Ai rline Modi fia ble Inform a t ion
A M L C D Act ive Ma trix Liquid Crystal Display
A M M Ai rc raft Ma i n te n a nce Ma nu a l
A M P Au dio Ma n age ment Pa n e l
A M S ( 1 ) A pron Ma n age ment Service
( 2 ) Avion ics Ma n age ment Service
A M S ( R ) S Aeron au t ical Mo bi le Sa te l l i te (Ro u te) Service
A M S S Aeron au t ical Mo bi le Sa te l l i te Service
A M TO S S Ai rc raft Ma i n te n a nce Task Orie n ted Support Syste m .
An au tom a ted data re trieval syste m .
A M T S Aeron au t ical Message Tra n sfer Service
A M U Au dio Ma n age ment Un i t
A M U X Au dio Mul t i plexer
A N C Air Naviga t ion Com m i ss ion (ICAO )
A n e r o i d An evacu a ted and sea led caps ule or be l lows th a t
C a p s u l e expa n ds or con tracts in res pon se to ch a nges in press u re.
A N I C S A laskan NAS In terfac i l i ty Com mun ic a t ion Syste m
A N L P A R INC Ne twork Layer Pro toc ol
A N P Actual Naviga t ion Perform a nce
A N S ( 1 ) Am bient Noi se Se n sor
( 2 ) Area Naviga t ion Syste m
A N S I American Na t ional Sta n d a rds In st i t u te
A N T An te n n a
A N TC Adva nced Ne twor ki ng Test Center
AOA Ang le Of At tack
AO C ( 1 ) Aeron au t ical Opera t ional Con trol
( 2 ) Ai rc raft Opera t ional Con trol
( 3 ) Ai rline Opera t ional Con trol
( 4 ) Ai rport Obstruct ion Ch a rt
( 5 ) Ai rport Opera t ional Com mun ic a t ion s
AO C C Ai rline Opera t ion Con trol Center
AO D Au dio on De m a n d
8
1 1
A S C I I American Sta n d a rd Code for Inform a t ion In terch a nge
A S C P C Air Supply and Cabin Press u re Con trol ler s
A S D Ai rc raft Situation Display
A S D E Ai rport Surface De tect ion Equi pme n t
A S D L Aeron au t ical Sa te l l i te Da ta Link
A S E A l t i me try System Error
A S E C N A Age ncy for the Secu ri ty of Aerial Naviga t ion in
Africa and Ma d aga sc a r
A S G A R INC Signal Ga teway
A S I Avion ics System In tegra t ion
A S I C A p pl ic a t ion Spec i fic In tegra ted Circui t
A S M ( 1 ) Ai r s pace Ma n age me n t
( 2 ) Au to th ro t tle Servo Mo tor
A S N. 1 Abstract Syn tax No ta t ion One
A S O S Au tom a ted Surface Observi ng Syste m
A S P ( 1 ) Altitude Set Pa n e l
( 2 ) Aeron au t ical Fi xed Service (AFS) Syste m s
Pla n n i ng for data interch a nge
A S P P Aeron au t ical Fi xed Service (AFS) Systems Pla n n i ng
for data interch a nge Pa n e l
A-S M G C S Adva nced Surface Move ment Guid a nce and
C on trol Syste m s
A S R Ai rport Surve i l la nce Radar
A S R S Avia t ion Safe ty Re port i ng Syste m
A S S TC Aeros pace Simula t ion and Systems Test Center
A S T F Ai r s pace System Task Force
A S U Avion ics Swi tch i ng Un i t
A S S V A l tern a te So u rce Se lect ion Va lve
A S TA Ai rport Surface Traffic Au tom a t ion
A P U C Auxi l ia ry Power Unit Con trol ler
AQ F Avion ics Qualific a t ion Fac i l i ty
AQ P ( 1 ) Adva nced Qualific a t ion Progra m
( 2 ) Avion ics Qualific a t ion Procedu re
A-Q P S K Aeron au t ical Quadra t u re Phase Shift Keyi ng
AQ S Adva nced Quality Syste m
A R AC Avia t ion Rule m aki ng Advi sory Com m i t tee
A R B Ar bi tra ry Waveform Ge n era tor
A R F Ai rline Risk Factor
A R I N C Aeron au t ical Radio, INC orpora ted
ARINC 429-13 Mark 33 Digi tal Inform a t ion Tra n sfer System (DITS ),
S u p ple ment 13
ARINC 629-2 Mul t i - Tester Da ta Bus: Pa rt 1 - Tech n ical Desc ri p t ion
A R M C Area Regional Ma i n te n a nce Center
A R P ( 1 ) Aeron au t ical Rec om me n d ed Pract ice
( 2 ) Air Da ta Refere nce Pa n e l
A R PA Adva nced Resea rch Projects Age nc y
A R R Arriva l
A R S Au tom a ted Radar Sum m a ry ch a rt .T h ese are hourly
ge n era ted ch a rts showi ng loc a t ion and inte n s i ty of
radar ech oes.
A R S R Air Ro u te Surve i l la nce Radar
A R T Au tom a t ic Reserve T h rust
A R TC C Ai r- Ro u te Traffic Con trol Center. A p proxi m a te ly 20
ce n ters cover the air traffic ro u tes in the Un i ted Sta tes
us i ng numero us radars and ra dio com mun ic a t ion se ts.
A R T S Au tom a ted Terminal Radar Syste m
A S A ( 1 ) Ai rc raft Se pa ra t ion Ass u ra nce
( 2 ) Au toland Sta t us An nunc ia tor (AF DS )
A S A A ACA RS System Access A p proval (AEEC )
A S A S Ai rc raft Se pa ra t ion Ass u ra nce System (AEEC )
1 0
1 3
AT S G F Air Traffic Services Geogra p h ic Fi l ter
AT S M Air Traffic Services Message Processor
AT S U Air Traffic Services Un i t
AT T At t i t u d e
AU X Auxi l ia ry
AV I O N I C S Avia t ion Electron ic s
AV L A N Avion ics Local Area Ne twor k
AV L C Avia t ion VHF Link Con trol
AV M Ai r borne Vi bra t ion Mon i tor
AVO L Aerodrome Vi s i bi l i ty Opera t ional Leve l
AV PAC Avia t ion Packet Com mun ic a t ion
AWAC S Ai r borne Wa rn i ng And Con trol Syste m
AWA S Au tom a ted Wea th er Advi sory Sta t ion
AW G American Wi re Gauge
AW I N Avia t ion Wea th er Inform a t ion
AW I P S Adva nced Wea th er In teract ive Process i ng Syste m
AW M Au dio Wa rn i ng Mixer
AW O All Wea th er Opera t ion s
AW O P All Wea th er Opera t ions Pa n e l
AW O S Au tom a ted Wea th er Observa t ion Syste m . A syste m
that ga th ers surface wea th er inform a t ion and
tra n s m i ts the inform a t ion to the pi lot via VOR,
C omm Freq or te le p h one lines.
B a n d w i d t h The di ffere nce be tween the hig h est and lowest
freque ncy com pon e n ts of a sign a l .
B A P Ba nk Ang le Pro tect ion
B A R O Ba rome tric
B a r o-C o r r e c t e d P ress u re altitude-corrected local ba rome tric press u re.
A l t i t u d e
B ATA P Type B A p pl ic a t ion to A p pl ic a t ion Pro toc ol
AT ( 1 ) Air Traffic
( 2 ) Air Tra n s port
A / T Au to th ro t tle
ATA ( 1 ) Actual Ti me of Arriva l
( 2 ) Air Tra n s port Assoc ia t ion
ATC Air Traffic Con trol
ATC A Air Traffic Con trol Assoc ia t ion
ATC C Air Traffic Con trol Center
ATCR B S Air Traffic Con trol Radar Beac on Syste m
ATC S S Air Traffic Con trol Sign a l i ng Syste m . A system to
provide inform a t ion be tween the pi lot and air traffic
c on trol us i ng the VHF com mun ic a t ions tra n sce iver
in con j unct ion wi th data link equi pme n t .
AT E Au tom a t ic Test Equi pme n t
AT F M Air Traffic Flow Ma n age me n t
AT H R Au to th rust Syste m
AT H S Au tom a t ic Ta rget Ha n d off Syste m
AT I In strument Size Unit of Mea s u re
AT I S ( 1 ) Air Traffic Inform a t ion Service
( 2 ) Au tom a t ic Terminal Inform a t ion Service
( 3 ) Au tom a t ic Terminal Inform a t ion Syste m
AT L A S Ab brevia ted Test Langu age for Avion ics Syste m s
AT M ( 1 ) Air Traffic Ma n age me n t
( 2 ) Asynch ron o us Tra n sfer Mod e
AT N Aeron au t ical Te lec om mun ic a t ions Ne twor k
AT N P Aeron au t ical Te lec om mun ic a t ion Ne twork Pa n e l
AT P Acce p ta nce Test Procedu re (Air Tra n s port )
AT R Air Tra n s port Racki ng
AT S ( 1 ) Air Traffic Services
( 2 ) Air Tu r bine Sta rter
( 3 ) Au to th ro t tle Syste m
AT S C Air Traffic Service Com mun ic a t ion
1 2
1 5
B i t A bi n a ry digi t . S m a l lest data unit in a mic ro processor
syste m .
B I T B ui l t - In - Test
B I T E B ui l t - In - Test Equi pme n t
B L K ( 1 ) Black
( 2 ) Block
B M V Brake Me teri ng Va lve
B N R Bi n a ry
B N S Bo un d a ry No t i fic a t ion System (Squi t ter s )
B O C Bo t tom Of Climb
B O M Bill Of Ma teria l
B O P Bit Orie n ted Pro toc ol
B o r e s i g h t i n g The process of align i ng a di rect ional antenna syste m .
B P ( 1 ) BITE P rocessor
( 2 ) Bo t tom Pl ug
B P C U B us Power Con trol Un i t
b p s bi tes per sec on d
B p s Bytes per sec on d
B P S K Bi n a ry Phase Shift Keyi ng
B R Bridge
B R G Bea ri ng
B R I Ba s ic Rate In terface
B R N AV Ba s ic Area Naviga t ion
B R T Brig h tn ess
B S C U Brake System Con trol Un i t
B S N Backbone Subnetwor k
B S P Boa rd Support Pack age
B S U ( 1 ) Beam Steeri ng Un i t
( 2 ) Bypa ss Swi tch Un i t
B T B B us Tie Breaker
B B Ba se Ba n d
B C D Bi n a ry Cod ed Dec i m a l .A c odi ng system in wh ich
each digit from 0 to 9 is re prese n ted by a four bit
bi n a ry num ber.
B CRS Back Course
B C S Block Check Seque nce. BCS is a cyc l ic code that is
used as refere nce bi ts in an error detect ion process.
B D I Bea ri ng Dista nce In dic a tor
B D M I S B us i n ess Da ta Ma n age ment and Invoic i ng
Beam Wi d t h The beam width is the width of the beam as
mea s u red at the half-power poi n ts of the ra dia ted
s ignal ( W X R ).
B e a r i n g The di rect ion of a point or naviga t ional aid mea s u red
c lockwi se from a refere nce th ro ugh 360 ° .
B E P Back - End Processor
B E P M S Back - End Processor Ma n age ment Syste m
B E R Bi te Error Rate
B F E B uyer Fu rn i s h ed Equi pme n t
B F O Beat Freque ncy Osc i l la tor. An osc i l la tor that produces
a signal to be mixed wi th the rece ived freque ncy to
produce an au di ble beat note, for the purpose of
d ec odi ng the Mor se code id e n t i fier of an NDB. T h e
osc i l la tor produces freque nc ies equal to the sum and
di ffere nce of the com bi n ed freque nc ies.
B G I B us Grant Inh i bi t . A term used in CA PS tra n sfer
b us process i ng.
B G P Bord er Ga teway Pro toc ol
B I B u rn - In
B i G S Bi l i ngual Gro und Sta t ion (ACA RS and V DML 2 )
B i n a r y Ba se-2 coun t i ng syste m . N um bers include 0, 1.
B I S Bo un d a ry In termedia te Syste m
B I S M S BIS Ma n age ment Syste m
B I S T B ui l t - In Self Test
1 4
1 7
C A S E C om p u ter Aid ed Softwa re Engi n eeri ng
C AT ( 1 ) C a tegories (I, I I, III) for Vi s i bi l i ty Requi re me n ts
( 2 ) C lear Air Tu r b ule nce
( 3 ) C om p u ter Aid ed Test i ng
CAT I O pera t ional perform a nce Category I. An ILS fac i l i ty
providi ng opera t ion down to a 60 - me ter (200 fee t )
d ec i s ion height and wi th runway visual ra nge not less
than 800 me ters (2600 feet) and a high pro ba bi l i ty of
a p proach success.
CAT I An ILS A p proach to lower- th a n - sta n d a rd Category I
E n h a n c e d and in some cases to Category II, m i n i mum s, ba sed
on guid a nce - to - to uch d own provid ed by a Category
I I I - c a pa ble Head-up Guid a nce Syste m , per FA A O rd er
8400.13.
CAT II O pera t ional perform a nce Category II. An ILS fac i l i ty
providi ng opera t ion down to a 30 - me ter (100 fee t )
d ec i s ion height and wi th runway visual ra nge not less
than 400 me ters (1200 feet) and a high pro ba bi l i ty of
a p proach success.
CAT III a O pera t ional perform a nce Category III a. An ILS fac i l i ty
providi ng opera t ion wi th no dec i s ion height limit to
and along the surface of the runway wi th extern a l
visual refere nce du ri ng final phase of la n di ng and
wi th a runway visual ra nge of not less than 200 me ter s
( 700 fee t ).
CAT III b O pera t ional perform a nce Category III b. An ILS
fac i l i ty providi ng opera t ion wi th no dec i s ion heig h t
limit to and along the surface of the runway wi th o u t
re l ia nce on external visual refere nce; and subseque n tly ta xi i ng wi th external visual ra nge of not
less than 50 me ters (150 fee t ).
CAT III c O pera t ional perform a nce Category III c. An ILS
fac i l i ty providi ng opera t ion wi th no dec i s ion heig h t
limit to and along the surface of the runway and
ta xi ways wi thout re l ia nce on external visual refere nce.
C AT EVS C lear Air Tu r b ule nce Enh a nced Vi s ion Syste m
C- B A N D The freque ncy ra nge be tween 4,000 and 8,000 MHz.
C B T C om p u ter- Ba sed Tra i n i ng
C C C - C h eck
B T M U Brake Te m pera t u re Mon i tor Un i t
B WA N Backup WA N
B y t e A gro u pi ng of eight bi ts.
C & C C ommand and Con trol
C & W C on trol and Wa rn i ng
CA A C ivil Avia t ion Au th ori ty. A regula tory age ncy in th e
Un i ted Ki ngd om .
C A AC C ivil Avia t ion Adm i n i stra t ion of China
CAC C au t ion Advi sory Com p u ter
C /A Code ( 1 ) C o u r se Acqui s i t ion Cod e
( 2 ) G PS Course Acqui s i t ion Cod e
C AC P C a bin Area Con trol Pa n e l
CA D C om p u ter Aid ed Des ign
C A DAG C om mun ic a t ions Au tom a t ion and Da ta Link
CA E C om ponent A p pl ic a t ion Engi n eer
CAG E C om merc ial Avion ics GPS Engi n e
C A H C a bin At tendant Ha n dse ts
CA I C au t ion An nunc ia tor In dic a tor
C a l i b r a t e d C orrected for instrument errors and errors due to
A i r s p e e d pos i t ion or loc a t ion of the press u re so u rce. At
sta n d a rd sea level con di t ion s, CAS is equal to true
a i r s peed (TA S ).
CA L S E L A va ria t ion of the SE LCA L system in wh ich th e
SE LCA L s ignal is com bi n ed wi th a spec ial ga t i ng ton e
to produce an au tom a t ic funct ion by the rece iver. T h i s
system is only a pro posal and not yet imple me n ted.
CAL VER C a l i bra t ion Veri fic a t ion
CA M C om p u ter Aid ed Ma nu fact u ri ng
CA P T C a p ta i n
Ca r r i e r An ac signal that can be modula ted by ch a ngi ng th e
a m pl i t u d e, freque ncy or pul se of the sign a l .
CA S ( 1 ) C ol l i s ion Avoid a nce Syste m
( 2 ) C om p u ted Ai r s peed
1 6
1 9
C E U C h eckl i st En try Un i t
C F C h a nge Fie ld
CF D I U C e n tral Fault Display In terface Un i t
CF D S C e n tra l ized Fault Display Syste m
C F I T C on trol led Fl ight In to Terra i n
c f m C u bic Feet per Minu te
C F M U C e n tral Flow Ma n age ment Un i t
C F S C a bin Fi le Server
C G C e n ter of Gravi ty
CH G ( 1 ) C h a nge
( 2 ) C h a rge
C H I C om p u ter Human In terface
C H I S C e n ter Hydraul ic Isola t ion Syste m
CH O L C ollins High Ord er Langu age
CI ( 1 ) C a bin In terp h on e
( 2 ) C onfigu ra t ion Ite m
C I D C a tegory In teract ion Diagra m
CI D I N C om m on ICAO Da ta In terch a nge Ne twor k
CI D S C a bin In terp h one Distri b u t ion Syste m
CI E C om m i ss ion In tern a t ion a le de I Ecla i rage
C I S C orpora te Inform a t ion Syste m
CLB C l i m b
CLK C lock
C L N P C on n ect ionless Ne twork Pro toc ol
C L N S C on n ect ionless Ne twork Service
Cl o u d Wa ter or ice pa rt ic les havi ng ra dii smaller th a n
D r o p l e t s 0.01 c m
CLR C lea r
C LT P C on n ect ionless Mode Tra n s port Pro toc ol
C C B ( 1 ) C onfigu ra t ion Con trol Boa rd
( 2 ) C onverter Circuit Breaker
C C D ( 1 ) C h a rged Coupled Device
( 2 ) C u r sor Con trol Device
C C I R In tern a t ional Radio Con s ul ta t ive Com m i t tee
C C I T T C on s ul ta t ive Com m i t tee In tern a t ional Te le p h on e
and Te legra p h
C C M S C on tent Com pi la t ion Ma n age ment Syste m
C C S C a bin Com mun ic a t ion Syste m
C C U C on trol and Com pe n sa t ion Un i t
C C W C o un terc lockwi se
CD ( 1 ) C a rrier De tect
( 2 ) C h rom i n a nce Differe nce
( 3 ) C om pact Disc
C DA C oordi n a t i ng Des ign Au th ori ty
C D B R C a bin Da ta Bus Re pea ter
C D G C onfigu ra t ion Da ta ba se Ge n era tor
CDI C o u r se Devia t ion In dic a tor
CDL C a bin Disc re pa ncy Log
C D M C ol la bora t ive Dec i s ion Maki ng
C D M S C ol la bora t ive Dec i s ion Maki ng Syste m
CDP C on t i nu o us Da ta Progra m
CDR C ri t ical Des ign Review
CD- R O M C om pact Disc Rea d - O nly Me m ory
C D S ( 1 ) C a bin Distri b u t ion Syste m
( 2 ) C om m on Display Syste m
C D T I C ock pit Display of Traffic Inform a t ion
CD U C on trol Display Un i t
C E P T C onfere nce Europèene des Postes et
Te l è c om mun ic a t ion s
1 8
2 1
C o m p a s s A low - powered ra dio beac on , used in con j unct ion
L o c a t o r wi th ILS. A c om pa ss loc a tor has a two - le t ter
id e n t i fic a t ion and a ra nge of at lea st 15 miles.
CO M P C om pressor
CO N C on t i nu o us
Cone of An inverted con ical shaped area exte n di ng vert ic a l ly
C o n f u s i o n a bove a VOR gro und fac i l i ty that is void of th e
bea ri ng sign a l .
CO N O P S C oncept of Opera t ion s
C o n s o l a n A low - freque nc y, keyed, C W, s h ort ba seline syste m
us i ng two antennas to ra dia te a daisy - s h a ped pa t tern
for naviga t ional aid purposes. The freque ncy ra nge is
in the 300 kHz region . It is in limited use tod ay.
C o n t o u r C on tour or iso - c on tour refers to a wea th er ra d a r
di s play prese n ta t ion that bla nks the echo re t u rns in
the ce n ter of a storm ce l l . The area bla nked out is
c a l led con tour and corres pon ds to the re t u rn leve l s
that exceed a pred e term i n ed th res h old.
C O N U S C on t i n e n tal Un i ted Sta tes
C O P C h a racter- O rie n ted Pro toc ol
CO ROUTE C om pa ny Ro u te
C o r r e c t i o n A c orrect ion is appl ied to sta t ic so u rce press u re
( S S E C ) mea s u re me n ts to pa rtly or com ple te ly correct for
press u re errors that are caused by airflow ch a nges. It is
c om p u ted as a funct ion of Mach and altitude ba sed on
mea s u red errors for a pa rt icular sta t ic syste m .
Corrective A resol u t ion advi sory that instructs the pi lot to
A d v i s o r y d evia te from cu rrent vert ical ra te (e. g. DON’ T C LIMB
when the airc raft is climbi ng ). ( TCA S )
C OT P C on n ect ion Orie n ted Tra n s port Pro toc ol
C OT S C om merc ial Off - T h e - S h e l f
C P ( 1 ) C i rcular Pola riz a t ion
( 2 ) C onfl ict Pro be
( 3 ) C on trol Pa n e l
C PA C losest Point of A p proach
C M C on text Ma n age me n t
CM A C e n tral Ma i n te n a nce A p pl ic a t ion
CMC C e n tral Ma i n te n a nce Com p u ter
CMCF C e n tral Ma i n te n a nce Com p u ter Funct ion
CMCS C e n tral Ma i n te n a nce Com p u ter Syste m
CMD C om m a n d
C M F C om m on Message Form a t
CMM ( 1 ) C om m on Mode Mon i tor. A type of mon i tor
c om m on to au tom a t ic fl ight con trol syste m s.
( 2 ) C om ponent Ma i n te n a nce Ma nu a l
CMN C on trol Mo t ion Noi se
C M P C onfigu ra t ion Ma n age ment Pla n
CMS C a bin Ma n age ment Syste m
C M O S C om ple me n ta ry Me tal Oxide Se m ic on ductor
CM U C om mun ic a t ions Ma n age ment Un i t
C N D B C ustom ized Naviga t ion Da ta ba se
CN E S C e n tre national d’ e t u d es spa t ia les
C/N O C a rrier- to - Noi se De n s i ty Ratio
C N P C om m / Nav / P ul se
CN S C om mun ic a t ion , Naviga t ion , S u rve i l la nce
CN S / AT M C om mun ic a t ion , Naviga t ion , S u rve i l la nce / Air Traffic
Ma n age me n t
C o a s t e d A track that is con t i nued ba sed on previo us track
Tr a c k ch a racteri st ics in the abse nce of surve i l la nce data
re ports (TCA S ).
CO D E C C od er / Dec od er
C O M C ock pit Opera t i ng Ma nu a l
C O M / M E T / O P SC om mun ic a t ion s / Me teorologic a l / O pera t ion s
CO M M C om mun ic a t ion s
2 0
2 3
C S C om m on Service
CS C C a rgo System Con trol ler
C S C I C om p u ter Softwa re Configu ra t ion Ite m
CSCP C a bin System Con trol Pa n e l
CS D B C om merc ial Sta n d a rd Da ta Bus
CS D S C a rgo Smoke De tector Syste m
CS E U C on trol Systems Electron ics Un i t
C S F C om m a n d / S ta t us Fra me
C S M A C a rrier Se n se Mul t i ple Access
C S M A / C D C a rrier Se n se Mul t i ple Access wi th Col l i s ion
CS M M C rash Surviva ble Me m ory Modules
CS M U C a bin System Ma n age ment Un i t
C/S O I T C om mun ic a t ion s /S u rve i l la nce Opera t ion a l
Im ple me n ta t ion Tea m
CS U C onfigu ra t ion Stra p pi ng Un i t
C TA ( 1 ) C on trol Area (ICAO Term )
( 2 ) C on trol led Ti me of Arriva l
C TA F C om m on Traffic Advi sory Freque nc y
CTA I C owl T h ermal An t i - Ic i ng
CTA S C e n ter Trac on Au tom a t ion Syste m
C TC C a bin Te m pera t u re Con trol ler
CT L C on trol
CT M O C e n tra l ized Air Traffic Flow Ma n age me n t
O rga n iz a t ion
CTO L C onve n t ional Take Off and Landi ng
C T R ( 1 ) C e n ter
( 2 ) C on trol zon e
CT R D C onfigu ra t ion Test Requi re me n ts Docume n t
C T R L C on trol
CP C ( 1 ) C a bin Press u re Con trol ler
( 2 ) C on trol ler Pilot Com mun ic a t ion
( 3 ) C u r sor Pos i t ion Con trol
CPCI C om p u ter Program Configu ra t ion Ite m . A CPCI
num ber id e n t i fies the configu ra t ion of a com p u ter
softwa re progra m .
C P C S C a bin Press u re Con trol Syste m
C P D L C C on trol ler- P i lot Da ta Link Com mun ic a t ion s
CP E C i rcular Pos i t ion Error
CP M C ore Processor Module
CPN C ollins Pa rt Num ber
CP R S R C om pressor
CP S C a bin Press u re Se n sor
CP U C e n tral Process i ng Un i t
C / R C om m a n d / Res pon se
CR ( 1 ) C h a nge Request
( 2 ) C on tra st Ratio
CR C ( 1 ) Cyc l ic Redun d a ncy Checki ng
( 2 ) Cyc l ic Redun d a ncy Cod e
CR E S C orros ion Res i stant Stee l
C R D C u rrent Ro u t i ng Dom a i n
C R DA C oo pera t ive Resea rch and Deve lo pment Agree me n t
C R M ( 1 ) C ock pit Reso u rce Ma n age me n t
( 2 ) C ol l i s ion Risk Mod e l
( 3 ) C rew Reso u rce Ma n age me n t
CR PA C on trol led Rece p t ion Pa t tern An te n n a
C R R C u tover Rea di n ess Review
CR S C o u r se
CR T C a th ode Ray Tu be
C R U C om p u ter Rece iver Un i t
CR Z C rui se
2 2
2 5
DA S Des ign a ted A l tera t ion Sta t ion
Data Link A system that allows exch a nge of digi tal data over an
RF link. ATC SS is a data link system used by the air
traffic con trol syste m . ACA RS is a data link syste m
used by airline com m a n d, c on trol and manage me n t
syste m , us i ng VHF com mun ic a t ion freque nc ies.
D-AT I S D igi tal Au tom a t ic Terminal Inform a t ion Syste m
D B Da ta ba se
d B Dec i be l
d B A Dec i bels Ad j usted
D B i ( 1 ) Dec i bels above iso to pic circula r
( 2 ) Dec i bels refere nced to an iso to pic ante n n a
D B I Downl i nk Block Id e n t i fier
d B m Dec i bel(s) be low 1 m i l l i wa t t
D B M X Da ta ba se Ma n age ment Syste m
D B S D i rect Broa d c a st Sa te l l i te
D B w Dec i bels refere nced to 1 wa t t
d B W Dec i be l -Wa t ts
D B U Da ta ba se Un i t
D C D i rect Curre n t
D C A S D igi tal Con trol Au dio Syste m
D C D Do u ble Channel Duplex . A c om mun ic a t ion system
us i ng two RF ch a n n e l s, one channel for rece ive and
one channel for transmit opera t ion s, for simul ta n eo us
c om mun ic a t ion .
D C E Da ta Com mun ic a t ions Equi pme n t
D C G F Da ta Conver s ion Ga teway Funct ion
D C M F Da ta Com mun ic a t ion Ma n age ment Funct ion
D C M S Da ta Com mun ic a t ion Ma n age ment Syste m
D C N ( 1 ) Des ign Change No t ice
( 2 ) Document Change No t ice
( 3 ) D rawi ng Change No t ice
CT S C lear To Se n d
CT U C a bin Te lec om mun ic a t ions Un i t
C U ( 1 ) Channel Utiliz a t ion
( 2 ) C om bi n er Unit (HUD)
( 3 ) C on trol Un i t
C / U T C od e / Unit Test
C V / D F D R C ock pit Voice and Digi tal Fl ight Da ta Rec ord er
CVR C ock pit Voice Rec ord er
CVR C P C ock pit Voice Rec ord er Con trol Pa n e l
CW ( 1 ) C lockwi se (cw)
( 2 ) C on t i nu o us Wave. A c on t i nu o us train of
id e n t ical osc i l la t ion s.
C W C C om pa ra tor Wa rn i ng Com p u ter
CW I C on t i nu o us Wave In terfere nce
CW P ( 1 ) C on trol led Wor ki ng Pos i t ion
( 2 ) C on trol ler Wor ki ng Pos i t ion
CW S C on trol W h eel Steeri ng
D 8 P S K D i ffere n t ial Eight Phase Shift Keyi ng
D & O Desc ri p t ion and Opera t ion
DA ( 1 ) Descent Advi sor
( 2 ) D ri ft Ang le
D / A D igi ta l - to - An a log
DA B S D i sc re te Ad dressa ble Beac on Syste m
DA D C D igi tal Air Da ta Com p u ter
DA D S D igi tal Air Da ta Syste m
DA P D igi tal Service Access Product
DA R C D i rect Access Radar Channel. An independent back u p
to main ATC com p u ter s.
DA R PA Defe n se Adva nced Resea rch Projects Age nc y
DA R P S D yn a m ic Ai rc raft Ro u te Pla n n i ng Study
2 4
2 7
D e m a n d An ACA RS mode of opera t ion in wh ich
M o d e c om mun ic a t ions may be initia ted by the gro un d
processor or the airborne syste m .
D E P De pa rt u re
D E R Des ign a ted Engi n eeri ng Re prese n ta t ive
D E S Desce n t
D E S C R Desc ri p t ion
D e s e n s i t i z a t i o n TCAS se n s i t ivi ty level (th reat vol ume) reduct ion
D E S T Dest i n a t ion
D E V Devia t ion
D FA D i rect ion Fi n di ng An te n n a
DFCS D igi tal Fl ight Con trol Syste m
D F DA F D igi tal Fl ight Da ta Acqui s i t ion Funct ion
D F DA M U D igi tal Fl ight Da ta Acqui s i t ion Ma n age ment Un i t
D F DAU D igi tal Fl ight Da ta Acqui s i t ion Un i t . The DF DAU
sa m ples, c on di t ions and digi t izes the fl ight data .
DFDR D igi tal Fl ight Da ta Rec ord er
D F D U D igi tal Fl ight Da ta Un i t
DFI D U Dual Funct ion In teract ive Display Un i t
DFI U D igi tal Fl ight In strument Un i t
D F S D igi tal Freque ncy Se lect
D F U D igi tal Funct ion Un i t
D G D i rect ional Gyro
D G N S S D i ffere n t ial Glo bal Naviga t ion Sa te l l i te Syste m
D G P S D i ffere n t ial Glo bal Pos i t ion i ng Syste m
D H ( 1 ) Da taflash Hea d er
( 2 ) Dec i s ion He ig h t
D I Da ta In terru p t
D I AG S D iagra m s
D I D Da ta Item Desc ri p t ion
D C P D i s play Con trol Pa n e l
D C S Do u ble Channel Simplex . A c om mun ic a t ion syste m
us i ng two RF channels for non - s i mul ta n eo us
c om mun ic a t ion . One channel is di sa bled wh i le the
o th er channel is used to tra n s m i t .
D C U Da ta Conce n tra tor Un i t
D C V D i rect ional Con trol Va lve
D D Da ta De l ivery
D DA ( 1 ) D igi tal Differe n t ial An a lyzer
( 2 ) D i sta nce Da ta Ad a p ter
D D D Dual Disk Drive
D D I D i rect Dial In dic a tor
D D M D i ffere nce in De p th of Modula t ion
D D P Dec la ra t ions of Des ign and Perform a nce. A c on trol
d ocument requi red by the Un i ted Ki ngd om Civi l
Avia t ion Au th ori ty (CAA) for cert i fic a t ion of avion ic s
equi pme n t .
D D R D raft Document Review
D D S D i rect Digi tal Syn th es izer
D D T Downl i nk Da ta Tra n sfer
D D TC Da ta Link De l ivery of Expected Ta xi Clea ra nces
D E C C A A n aviga t ion system wid e ly used by shippi ng in
E u ro pe. The gro und fac i l i t ies con s i st of a master
sta t ion and several slave sta t ion s.
D e c i m a l Ba se -10 coun t i ng syste m . N um bers include
0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
d e d Dedic a ted
D E F DA R S D igi tal Expa n d a ble Fl ight Da ta Acqui s i t ion and
Rec ordi ng Syste m
D E F L Deflect ion
D E G Degree
D E L De le te
2 6
2 9
D L U Download Un i t
D M D i sc on n ected Mod e
D M A D i rect Me m ory Access
D M E D i sta nce Mea s u ri ng Equi pme n t . A system th a t
provid es di sta nce inform a t ion from a gro und sta t ion
to an airc raft .
D M E / N Ab brevia t ion for a DME normal syste m
D M E / P Ab brevia t ion for a DME prec i s ion syste m
D M I R Des ign a ted Ma nu fact u ri ng In s pect ion Re prese n ta t ive
D M M ( 1 ) Da ta Me m ory Module
( 2 ) D igi tal Mul t i me ter
D M N Da ta Mul t i plexi ng Ne twor k
D M S De bris Mon i tori ng Se n sor
D M U Da ta Ma n age ment Un i t
D O- 1 6 0 RTCA Document 160, Envi ronme n tal Con di t ions and
Test Procedu res for Ai r borne Equi pme n t , Iss ued
12 / 04 / 89
D O- 1 7 8 RTCA d ocument 178, Softwa re Con s id era t ions in
Ai r borne Systems and Equi pment Cert i fic a t ion ,
Iss ued 03 / 22 / 85
D O C Docume n ta t ion
D O D De pa rtment of Defe n se
D O O R S D yn a m ic Object Orie n ta ted Requi re me n ts Syste m
Doppler The ch a nge in freque ncy observed at the rece iver
E f f e c t when the tra n s m i t ter and rece iver are in motion
re la t ive to each oth er.
D O S Disk Opera t i ng Syste m
D OT De pa rtment of Tra n s porta t ion
D OT S D yn a m ic Ocean Tracki ng Syste m
D o w n l i n k The ra dio tra n s m i ss ion pa th downwa rd from th e
a i rc raft to the ea rth .
d p i d o ts per inch
D I P ( 1 ) Da ta In terrupt Progra m
( 2 ) Dual In-line Pack age. The most com m on
pack age configu ra t ion for integra ted circui ts.
D I R D i rector
D i r e c t e d A DME opera t i ng mode that allows an FMCS to
M o d e se lect one to five DME sta t ions for interroga t ion .
D I R / I N TC D i rect In terce p t
D I S C D i sc on n ect
D I S C H D i sch a rge
D I S C R D i sc re pa nc y
D I S T D i sta nce
D I T S Da ta Inform a t ion Tra n sfer Syste m
D L ( 1 ) Da ta Link
( 2 ) Downl i nk
D L A P Da ta Link A p pl ic a t ion Processor
D L C Da ta Link Con trol Display Un i t
D L C I Da ta Link Con trol Id e n t i fier
D L E Da ta Link En t i ty
D L G F Da ta Load Ga teway Funct ion
D L I Da ta Link In terpre ter progra m
D L K Da ta Link (AEEC )
D L L Da ta Link Libra ry
D L M Da ta Link Ma n age ment Un i t
D L M E Da ta Link and Message Engi n eeri ng
D L / M S U Da ta Loa d er / Ma ss Storage Un i t
D LO D S D uct Leak and Overh eat De tect ion
DLP Da ta Link Processor
D L S Da ta Load Syste m
D LT D igi tal Lineal Ta pe - used for the storage of vid eo
and au dio fi les
2 8
3 1
D T M F Dual Tone Mul t i - Freque nc y
D T M De m on stra t ion Test Mileston e
D T P D U Da ta Pro toc ol Da ta Un i t
D T U Da ta Tra n sfer Un i t
D U D i s play Un i t
Dual Mode An airborne DME RT c a pa ble of process i ng DME / N
D M E and DME/P gro und sta t ion sign a l s. O pera t ion is in
the L-band freque ncy ra nge.
D UAT D i rect User Access Term i n a l
D u p l ex A c om mun ic a t ion opera t ion that uses th e
s i mul ta n eo us opera t ion of the transmit and
rece ive equi pment at two loc a t ion s.
DV F De m on stra t ion and Va l id a t ion Fac i l i ty
DV M D igi tal Vol tme ter
DWA N D i rect WA N
D X D i sta nce
D y n a m i c D yn a m ic Press u re is the di ffere nce be tween pi tot and
P r e s s u r e sta t ic press u re.
D y n a m i c RAM con structed of capac i tor ele me n ts. Me m ory
R A M cells must be periodic a l ly refres h ed to keep capac i tor s
from di sch a rgi ng and los i ng data . ( See “S ta t ic RA M” )
E E a st
E A A E xperi me n tal Ai rc raft Assoc ia t ion
E A D I Electron ic Attitude Director In dic a tor
E A I Engine An t i - Ice
E A P Engine A lert Processor
E A R O M Electric a l ly A l tera ble ROM
E A R T S En ro u te Au tom a ted Radar Tracki ng Syste m
E A S E quiva lent Ai r s peed
E A S I E Enh a nced ATM and Mode S Im ple me n ta t ion
in Euro pe
D P R Dual Port RA M
D P S K D i ffere n t ial Phase Shift Keyi ng
D R ( 1 ) Da ta Rec on i ng
( 2 ) Da ta Rece p tac le
D R E R Des ign a ted Radio Engi n eeri ng Re prese n ta t ive (FA A )
Drift Angle The ang le be tween hea di ng and track. It is due to
the effect of wind cu rre n ts. Some t i mes called the
c rab ang le.
D R N Document Re lea se No t ice
D S A D D igi tal Service Access Device
D S A R C Defe n se System Acqui s i t ion Review Cyc le
D S B Do u ble Side Ba n d.An AM signal wi th the carrier
re m oved. Requi res the sa me ba n dwidth as the
AM sign a l .
D S D U Da ta Signal Display Un i t
D S F D i s play System Funct ion
D S P ( 1 ) D igi tal Signal Processor
( 2 ) D i s play Se lect Pa n e l
( 3 ) Domain Spec i fic Pa rt
D S P D R V D i s play Driver
D S P Y D i s play (annunc ia t ion on CDU )
D S R D i s play System Re place me n t
D S S Dec i s ion Support Syste m s
D S S S D i rect Seque nce Spread Spectrum
D S U ( 1 ) Da ta Sign a l i ng Un i t
( 2 ) Domain Service Un i t
D T D ( 1 ) Da ta Terminal Display
( 2 ) Document Type Defi n i t ion
D T E Da ta Terminal Equi pme n t
DT & E Deve lo pment Test and Eva l u a t ion
D T G D i sta nce - to - go
3 0
E D D S Electron ic Document Distri b u t ion Service
E D I Engine Da ta In terface
E D I F Engine Da ta In terface Funct ion
E D I U Engine Da ta In terface Un i t
E D M S Electron ic Da ta Ma n age ment System
E D P ( 1 ) Electron ic Da ta Process i ng
( 2 ) Engine Driven Pum p
( 3 ) Engi n eeri ng Deve lo pment Pa l le t
E D U Electron ic Display Un i t
E E Electron ics Equi pment (e. g. E E- Bay )
E E C Electron ic Engine Con trol
E E P R O M Electrical Era sa ble Progra m m a ble Read Only Me m ory
E E U E LMS Electron ics Un i t
E F C E xpected Fu rth er Clea ra nce
E F D Electron ic Fl ight Display
E F D R E xpa n d ed Fl ight Da ta Rec ord er
E F I C Electron ic Fl ight In strument Con trol ler
E F I P Electron ic Fl ight In strument Processor
EFI S Electron ic Fl ight In strument Syste m
EFIS CP E FIS C on trol Pa n e l
E G I H O E xpedi ted Gro und In i t ia ted Ha n d off
E E LV Evolved Expe n d a ble Launch Ve h ic le
E G N O S E u ro pean Geosta t ion a ry Overlay Syste m
E G P E xterior Ga teway Pro toc ol
E G P W S Enh a nced Gro und Proxi m i ty Wa rn i ng Syste m
E GT E x h aust Gas Te m pera t u re
E H S I Electron ic Horizon tal Situation In dic a tor
E H V Electro - Hydraul ic Va lve
E ATC H I P E u ro pean Air Traffic Con trol Ha rm on iz a t ion and
In tegra t ion Progra m me
E AT M S E u ro pean Air Traffic Ma n age ment Syste m s
E B AC E E u ro pean Bus i n ess Avia t ion Conve n t ion and
E x h i bi t ion
E C Event Cri terion
E C AC E u ro pean Civil Avia t ion Confere nce
E C A M Electron ic Cau t ion A lert Module
E C A R S Enh a nced ACA RS
E C E F E a rth - C e n tered, E a rth - Fi xed
E c h o The port ion of the ra dia ted energy reflected back
to the antenna from the ta rget (WXR).
E C M Electron ic Con trol Module
E C M P Electron ic Com ponent Ma n age ment Syste m
E C O N E c on omy (minimum cost speed sch edule )
E C P E ICAS Con trol Pa n e l
E C S ( 1 ) Engi n eeri ng Com pi ler Syste m . An au tom a ted
d a ta storage syste m .
( 2 ) Envi ronme n tal Con trol Syste m
( 3 ) Event Cri terion Subfie ld
E C S L Left Envi ronme n tal Con trol System Card
E C S M C EC S M i sce l la n eo us Card
E C S R Right Envi ronme n tal Con trol System Card
E C U ( 1 ) E ICAS Con trol Un i t
( 2 ) Electron ic Con trol Un i t
( 3 ) E xternal Com pe n sa t ion Un i t
E D E ICA SD i s play
E / D En d - of - Desce n t
E DA Electron ic Des ign Au tom a t ion
E DAC E rror De tect ion and Correct ion
( used interch a ngea bly wi th EDC )
E D C E rror De tect ion and Correct ion
3 2 3 3
3 5
E O M End Of Message
E OT End Of Text
E P E xternal Power
E P C E xternal Power Con tactor
E P C S Engine Pro p ul s ion Con trol Syste m
E- P I R E P S Electron ic Pilot Re ports
E- P l a n e The E- Plane is the plane of an antenna that con ta i n s
the electric fie ld.The pri nc i pal E- Plane also con ta i n s
the di rect ion of maxi mum ra dia t ion .
E P L D Electric a l ly Progra m m a ble Logic Device
E P P Enh a nced Pa ra l lel Port
E P R Engine Press u re Ratio
E P R O M E ra sa ble Progra m m a ble ROM
E P S Electrical Power Syste m
E Q U I P E qui pme n t
E q u i v a l e n t E quiva lent Ai r s peed is a di rect mea s u re of th e
Airspeed i nc om press i ble freestream of dyn a m ic press u re.
( E A S ) It is CAS corrected for com press i bi l i ty effects.
ER PDU E cho Re ply Pro toc ol Da ta Un i t
E R A E u ro pean Regional Ai rl i n es Assoc ia t ion
E R B Engi n eeri ng Review Boa rd
E R D End Ro u t i ng Dom a i n
E R D I En Ro u te Domain Infra struct u re
E R E E xternal Roll Extrus ion
E R P Eye Refere nce Poi n t
ERP PDU E cho Re ply Pro toc ol Da ta Un i t
ERQ PDU E cho Request Pro toc ol Da ta Un i t
E R U Engine Re lay Un i t
E S End Syste m
E I A Electron ic In dustries Assoc ia t ion
E I C A S Engine In dic a t ion and Crew A lert Syste m
E I C A S C Engine In dic a t ion and Crew A lert System Con trol s
E I P I E xte n d ed In i t ial Pro toc ol Id e n t i fier
E I R P E a rth Inc ident Radia ted Power
E I S ( 1 ) Electron ic In strument Syste m
( 2 ) Engine In dic a t ion Syste m
E I S A E xte n d ed In dustry Sta n d a rd Arch i tect u re
E I U E FIS / E ICAS In terface Un i t
E L / F C G Electron ic Log book and Fault Correct ion Guid e
E L B / I S E Electron ic Log book In - Service Eva l u a t ion
E L C E m i t ter Coupled Logic
E L E C Electric a l
E L M E xte n d ed Le ng th Message
E L M S Electrical Load Ma n age ment Syste m
ELS Electron ic Libra ry System
E LT E merge ncy Loc a tor Tra n s m i t ter
E M Ele ment Ma n ager
E M C ( 1 ) Electrom agn e t ic Com pa t i bi l i ty
( 2 ) En terta i nment Mul t i plexer Con trol ler
E M E R E merge nc y
E M I Electro - Magn e t ic In terfere nce
E M S ( 1 ) E merge ncy Medical Services
( 2 ) Engine Ma n age ment Syste m
E N G Engi n e
E N O C Engi n eeri ng Ne twor k O pera t ions Center
E N Q En qui re
E / O Engi n e - O u t
E O D End Of Day
3 4
3 7
E U R E u ro pea n
E U R AT N E u ro pean AT N
E U R E T E u ro pean Tra n s port
E u r o c a e E u ro pean Orga n iz a t ion for Civil Avia t ion Electron ic s.
A regula tory age ncy for avion ics cert i fic a t ion in
E u ro pe.
E U R O-C O N T R O L E u ro pean Orga n iz a t ion for the Safe ty of Ai r
Naviga t ion Opera t ion s
E V E a rn ed Va l ue
E V M E rror Vector Magn i t u d e
E V S Enh a nced Vi s ion Syste m
E X E C E xecu t ive
F Fah re nh e i t
FA Final A p proach
FA A ( 1 ) Fed eral Avia t ion Adm i n i stra t ion (U. S.)
( 2 ) Fed eral Avia t ion Au th ori ty
FA ATC FA A Tech n ical Center (U. S.)
FAC Fl ight Augme n ta t ion Com p u ter
FA D E C Full Au th ori ty Digi tal Electron ic Con trol
FA F Final A p proach Fi x
FA I Fi r st Art ic le In s pect ion
Fan Marke r A m a r ker beac on used to provide id e n t i fic a t ion
of pos i t ions along airways. S ta n d a rd fan marker
produces an elliptic a l - s h a ped pa t tern . A sec ond
type produces a dum b be l l - s h a ped pa t tern .
FA N S Fu t u re Air Naviga t ion Syste m
FA R ( 1 ) Fed eral Acqui s i t ion Regula t ion
( 2 ) Fed eral Avia t ion Regula t ion
FA S T Final A p proach Spac i ng Tool
FAT Factory Acce p ta nce Test
F B L Fly - By - L ig h t
E S A E u ro pean Space Age nc y
E S A S ( 1 ) Electron ic Situation Awa re n ess Syste m
( 2 ) Enh a nced Situational Awa re n ess Syste m
E-S c a n Electron ic Sc a n n i ng
E S D Electrosta t ic Disch a rge
E S D S Electrosta t ic Se n s i t ive Devices. A l so kn own as ESSD.
E S H End System He l lo
E S I D Engine and System In dic a t ion Display
E S I S Engine and System In dic a t ion Syste m
E S R En ergy Storage / C on trol
E S S ( 1 ) Electron ic Swi tch i ng Syste m
( 2 ) Envi ronme n tal Stress Sc ree n i ng
E S S D Electro S ta t ic Se n s i t ive Devices. See also ESDS.
E S T E st i m a ted
E S U Envi ronme n tal Se n sor Un i t
E TA E st i m a ted Ti me of Arriva l
E T B ( 1 ) End of Block (ASC I I / IA5 ch a racter )
( 2 ) Engi n eeri ng Test Ba n d
E T D E st i m a ted Ti me of De pa rt u re
E T I Ela psed Ti me In dic a tor
E T M Ela psed Ti me Mea s u re me n t
E T M S Enh a nced Traffic Ma n age ment Syste m
E TO P S E xte n d ed Twin Engine Opera t ion s
E T P E qual Ti me Poi n t
E T R C E xpected Ta xi Ramp Clea ra nces
E T V S Enh a nced Terminal Voice Swi tch
E T X End of Tra n s m i ss ion
E UA F S Enh a nced Upper Air Forec a st Syste m
E U P S E xternal Un i n terru p t i ble Power Supply
3 6
3 9
F D R S Fl ight Da ta Rec ord er Syste m
F D S Fl ight Display Syste m
F D U Fl ux De tector Un i t
F E AT S Fu t u re Euro pean Air Traffic Ma n age ment Syste m
F E C Forwa rd Error Correct ion
F E P Front End Processor
F F Fuel Flow
F G C Fl ight Guid a nce Com p u ter
F H A Funct ional Haz a rd Assess me n t
F H S S Freque ncy Ho p ped Spread Spectrum
F H W Fault History Word
F I B Forwa rdi ng Inform a t ion Ba se
F I F O Fi r st In , Fi r st Out
F I M Fault Isola t ion Ma nu a l
F I R Fl ight Inform a t ion Region
F I S ( 1 ) Fl ight Inform a t ion Service
( 2 ) Fl ight Inform a t ion Syste m
( 3 ) Fl ight In strument Syste m
F I S- B Fl ight Inform a t ion Services - Broa d c a st
F I X Pos i t ion in space, us u a l ly on airc raft ’s fl ight pla n
F L ( 1 ) Fl ight Level (as in FL 410 ). This term i n ology is
used to desc ri be airc raft attitude when th e
a l t i me ter is set at QNE.
( 2 ) Foot Lambert
F L C H Fl ight Level Change
FLIR Forwa rd Loo ki ng Infra - Red
F L M Fl ight Line Ma i n te n a nce
F LT Fl ig h t
F LTA Forwa rd Loo ki ng Terrain Avoid a nce
F LT C T R L Fl ight Con trol
F B O Fi xed Ba se Opera tor
F B W Fly - By -Wi re
F C Foot Candles
F C A Funct ional Configu ra t ion Au di t
F C A F Fl ight Da ta Acqui s i t ion
F C C ( 1 ) Fed eral Com mun ic a t ions Com m i ss ion
( 2 ) Fl ight Con trol Com p u ter
F C D C Fl ight Cri t ical dc
F C P ( 1 ) Fl ight Con trol Pa n e l
( 2 ) Fl ight Con trol Processor
F C S ( 1 ) Fl ight Con trol Syste m
( 2 ) Fra me Check Seque nce
F D ( 1 ) Final Da ta
( 2 ) Fl ight Director
( 3 ) Fl ight Dyn a m ic s
F DA F Fl ight Da ta Acqui s i t ion Funct ion
F DAU Fl ight Da ta Acqui s i t ion Un i t
F D B Fl ight Plan Da ta Ba nk
F D E Fl ight De tect ion Exc l us ion
F D D I Fi ber Distri b u ted Da ta In terface
F D E P Fl ight Da ta En try Pa n e l
F D H Fl ight Deck Ha n dse t
F D I Fault De tect ion and Isola t ion
F D I O Fl ight Da ta Inp u t / O u tp u t
F D M Freque ncy Divi s ion Mul t i plex . A system wh ere th e
messages are tra n s m i t ted over a com m on pa th by
e m ployi ng a di fferent freque ncy band for each sign a l .
F D M A Freque ncy Divi s ion Mul t i ple Access
F D P S Fl ight Da ta Process i ng Syste m
F D R Fl ight Da ta Rec ord er
3 8
4 1
F Q R Formal Qualific a t ion Review
FR From
F R A Flap Re tract ion A l t i t u d e
F R A D Fra me Re lay Access Device
Framing A p ul se that is used to mark the begi n n i ng or end
P u l s e of the cod ed re ply pul ses.
F R E E R Free - Ro u te Experi me n tal Enc o un ter Resol u t ion
Free Scan A DME opera t i ng mode that will provide di sta nce
M o d e d a ta to all DME gro und sta t ions wi thin the DME
ra nge (LOS ).
F R E Q Freque nc y
Frequency The abi l i ty of a rece iver- tra n s m i t ter to ra pidly and
c on t i nu a l ly shift opera t i ng freque nc y.
F R M Fault Re port i ng Ma nu a l
F R M R Fra me Re ject
F R P Fed eral Radion aviga t ion Pla n
F R PA Fi xed Rece p t ion Pa t tern An te n n a
F R Q Freque nc y
F S A S Fl ight Service Au tom a t ion Syste m
F S E Fie ld Service Engi n eer
F S E U Flap Slat Electron ics Un i t
F S F Fl ight Safe ty Fo un d a t ion
F S S Fl ight Service Sta t ion
F T Funct ional Test
F T E Fl ight Tech n ical Error
F T P Fi le Tra n sfer Pro toc ol
F T P P Fault Tolerant Power Pa n e l
F W Fa i l u re Wa rn i ng
F W C Fl ight Wa rn i ng Com p u ter
F LT I N S T Fl ight In strume n t
F LW Forwa rd Loo ki ng Wi n ds h ear Radar
F M Freque ncy Modula t ion
F M A Fl ight Mode An nunc ia tor
F M C ( 1 ) Fl ight Director Con trol (FD)
( 2 ) Fl ight Ma n age ment Com p u ter (FMC S )
F M C F Fl ight Ma n age ment Com p u ter Funct ion
F M C S Fl ight Ma n age ment Com p u ter Syste m
F M C W Freque nc y - Modula ted Con t i nu o us Wave
F M E A Fa i l u re Mode and Effects An a lys i s
F M F Fl ight Ma n age ment Funct ion
F M P Fl ight Mode Pa n e l
F M S Fl ight Ma n age ment Syste m
F M U Fuel Me teri ng Un i t
F / O ( 1 ) Fi r st Officer
( 2 ) Fuel/Oil Cooler
F O C ( 1 ) Fuel/Oil Cooler
( 2 ) Full Opera t ional Capa bi l i ty
F O G Fi ber Optic Gyro
F O Q A Fl ight Opera t ions Quality Ass u ra nce
F PA ( 1 ) Fl ight Pa th Ang le
( 2 ) Focal Plane Array
FPAC Fl ight Pa th Acce lera t ion
FP C Fl ight Profi le Com pa ra tor
FP G A Fie ld Progra m m a ble Ga te Array
FP M Feet Per Minu te
F P V Fl ight Pa th Vector
F Q I S Fuel Quantity In dic a t i ng Syste m
F Q P U Fuel Quantity Processor Un i t
4 0
4 3
G GT F M G ro un d - G ro und Traffic Flow Ma n age me n t
G G R G ro un d - G ro und Ro u ter
G G S G lo bal Pos i t ion i ng System Gro und Sta t ion
G H G ro und Ha n dl i ng
G H z G igah ertz (bi l l ion hertz )
G I G roup Id e n t i fier
G I B GN SS In tegri ty Broa d c a st
G I C GN SS In tegri ty Channel
G I C B G ro un d - In i t ia ted Com m - B
G I G O Ga r bage - In Ga r bage - O u t
G I H O G ro und In i t ia ted Ha n d off
G L ( 1 ) G ro und Loc a t ion (ACA RS / AFE PS )
( 2 ) G roup Le ng th
G l i d e p a t h The approach pa th used by an airc raft du ri ng an
i n strument la n di ng or the port ion of the glid es lo pe
that inter sects the loc a l izer. The glid e pa th does not
provide guid a nce com ple te ly to a to uch d own point
on the runway.
G l i d e s l o p e The vert ical guid a nce port ion of an ILS syste m .
GLN S G PS Landi ng and Naviga t ion Syste m
GLN U G PS Landi ng and Naviga t ion Un i t
G LO N A S S G lo bal Naviga t ion Sa te l l i te Syste m
GLS ( 1 ) G PS Landi ng Syste m
( 2 ) Gun Layi ng Syste m
G L U G PS L a n di ng Un i t
G M Guid a nce Ma teria l
G M C G ro und Move ment Con trol
G M T G ree nwich Mean Ti me. GM T is a un iver sal time
sc a le ba sed upon the mean ang le of ro ta t ion of th e
ea rth about its axis in re la t ion to the sun . It is
refere nced to the pri me meridian that pa sses th ro ug h
G ree nwich , Eng la n d.
G M U G lo bal Ne twork Arch i tect u re
F W D Forwa rd
F W S Fl ight Wa rn i ng Syste m
F Y D S Fl ight Director / Yaw Da m per Syste m
G A ( 1 ) Ge n eral Avia t ion
( 2 ) Go Aro un d
G A A S Ga l i um Ar se n id e
G AC S Ge n e t ic ATN Com mun ic a t ions Service
G A I T G ro un d - ba sed Augme n ta t ion and In tegri ty
G A M A Ge n eral Avia t ion Ma nu fact u rers Assoc ia t ion
G AT M G lo bal Air Traffic Ma n age me n t
G B S T G ro un d - Ba sed Softwa re Tool
G b y t e G iga byte (bi l lon bytes )
G C A S G ro und Col l i s ion Avoid a nce Syste m
G C B Ge n era tor Circuit Breaker
G C C G ro und Cluster Con trol ler (ACA RS )
G C S G ro und Clutter Suppress ion
G C U Ge n era tor Con trol Un i t
G DLP G ro und Da ta Link Processor
G D O P Geome tric Dilution Of Prec i s ion . A term referri ng to
error introduced in a GPS calcula t ion due to th e
pos i t ion i ng of the sa te l l i tes and the rece iver.
G D P G ro und De lay Progra m
G E N Ge n era tor
G E O Geosta t ion a ry Earth Orbi t
G E S G ro und Earth Sta t ion
G F E Government Fu rn i s h ed Equi pme n t
G F I Ge n eral Format Id e n t i fier
G F S K Gauss ian Freque ncy Shift Keyi ng
G G ( 1 ) G ra p h ics Ge n era tor
( 2 ) G ro un d - G ro un d
4 2
4 5
Gray Code S pec ial bi n a ry code used to transmit altitude data
be tween fra m i ng pul ses of a tra n s pon d er re ply. A
c yc l ic code havi ng only one digit ch a nge at a time.
Used in Mode C to transmit airc raft ba rome tric
a l t i t u d e. A l so kn own as Gilham cod e.
G r o u n d A ra dio wave that travels along the ea rth’s surface.
Wa v e
G R P Geogra p h ic Refere nce Poi n t
G S ( 1 ) G l id es lo pe
( 2 ) G ro und Speed
G / S G l id es lo pe
G S C G ro und Sta t ion Con trol ler (ACA RS )
G S E G ro und Support Equi pme n t
G S I F G ro und Sta t ion Inform a t ion Fra me
G S M G lo bal Systems Mo bi le
G S M S G ro und Sta t ion Ma n age ment Syste m
G S P G la re Shie ld Pa n e l
G S V G ray Sc a le Vol tage ( s )
GT G rea ter T h a n
GTA Ge n eral Terms Agree me n t
GTC Da ta Link Gro und Terminal Com p u ter
GT R Ge n eral Tech n ical Requi re me n ts
G U I G ra p h ic / User In terface
G V E G ra p h ics Vector Engi n e
G W Ga teway
G W S G ra p h ical Wea th er Services
G y r o s c o p e A ro ta t i ng device that will maintain its original pla n e
of ro ta t ion , no matter wh ich di rect ion the gyrosc o pe
m o unt is turn ed.
H A D Ha rdwa re Arch i tect u re Docume n t
H A M S Hot Air Ma n age ment Syste m
G N D G ro un d
G N E G ross Naviga t ional Error
G N R G lo bal Naviga t ion Rece iver
G N S S G lo bal Naviga t ion Sa te l l i te Syste m
G N S S P G lo bal Naviga t ion Sa te l l i te System Pa n e l
G o n i o m e t e r A d evice that com bi n es the two signals from two loo p
a n te n n a s. The gon iome ter (or resolver) con tains two
fi xed coils and one ro ta t i ng coi l . The ro ta t i ng coil is
c on n ected to the A DF bea ri ng indic a tor needle to
i n dic a te the re la t ive bea ri ng from the airc raft to th e
N DB sta t ion . The mech a n ical pos i t ion of the ro tor
re prese n ts the bea ri ng of the sta t ion , and the pos i t ion
is electric a l ly tra n s m i t ted to the RMI.
G O S G rade of Service
G O S I P Government Open Systems In terc on n ect ion Profi le
G PA D I R S G lo bal Pos i t ion i ng, Air Da ta , In ert ial Refere nce Syste m
G P I B Ge n eral Purpose In strument Bus
G P P Ge n eral Purpose Processor
G P S ( 1 ) G lo bal Pos i t ion i ng System (See NAVSTA R )
( 2 ) G lo bal Pos i t ion i ng Sa te l l i te
GPS L1 G lo bal Pos i t ion i ng System L1 Freque nc y
G P S S U G lo bal Pos i t ion i ng System Se n sor Un i t
G P U G ro und Power Un i t
G P W C G ro und Proxi m i ty Wa rn i ng Com p u ter
G P W S G ro und Proxi m i ty Wa rn i ng Syste m
G R G ro und Ro u ter
G R I B G rid d ed Bi n a ry (Na t ional Wea th er Service
Mod e l O u tp u t )
G r a d i e n t The ra te at wh ich a va ria ble qu a n t i ty inc rea ses
or dec rea ses.
4 4
4 7
H G C Head-Up Guid a nce Com p u ter
H G S Head-Up Guid a nce Syste m
H H L D Hea di ng Hold
H I H ig h
H I C Head Im pact Cri teria
H I L Horizon tal In tegri ty Limit
H I R F ( 1 ) H igh In te n s i ty Radia ted Fie ld
( 2 ) H igh In te n s i ty Radio Freque nc y
H L C S H igh Lift Con trol Syste m
H L E H ig h er Layer En t i ty
H L L H igh Level Langu age
H M I Human Machine In terface
H M O S H igh De n s i ty Me tal Oxide Se m ic on ductor
H M U He ight Mon i tori ng Un i t
H O Ha n d off
H O W Hand Over Word
H P ( 1 ) H igh Press u re
( 2 ) Holdi ng Pa t tern
H PA H igh Power Am pl i fier
h Pa h ecto Pa sc a l
H P C H igh Press u re Com pressor
H - P l a n e The H-Plane is the plane in wh ich the magn e t ic fie ld
of the antenna lies. The H-Plane is perpe n dicular to
the E- Pla n e.
H P R H ig h - Power Re lay
H P R E S P ress u re A l t i t u d e
H P S OV H ig h - P ress u re Shutoff Va lve
H P T H ig h - P ress u re Tu r bi n e
H R D Home Ro u t i ng Dom a i n
H S A Horizon tal Sta bi l izer Act u a tor
H A R S H igh Altitude Ro u te Syste m
HCP Head-Up Con trol Pa n e l
HCI Human Com p u ter In terface
H C S Host Com p u ter Syste m
H C W Heavi ly Cold Wor ked Pipe and Tu be (Sea n - Free ™ )
H D B K Ha n dboo k
H D G Hea di ng
HDG SEL Hea di ng Se lect
H D I S K Ha rd Disk
H D L Hy brid Da ta Link
H D L C H ig h - Level Da ta Link Con trol
H D L C- B H ig h - Level Da ta Link Con trol - Ba la nced
H D L M S Hy brid Da ta Link Ma n age ment Syste m
H D O P Horizon tal Dilution of Prec i s ion
H D OT In ert ial Vert ical Speed
H D P Ha rdwa re Deve lo pment Pla n
H E Altitude Error
H e a d i n g The di rect ion of an airc raft pa th wi th res pect to
m agn e t ic or true north .
H F H igh Freque nc y. The port ion of the ra dio spectrum
from 3 to 30 MHz. HF com mun ic a t ion syste m s
o pera te in the 2 to 30 MHz port ion of the spectrum .
H F D L H ig h - Freque ncy Da ta Link
H F D M HF Da ta Mod e m
H F D R H igh Freque ncy Da ta Radio
H F N P D U H igh Freque ncy Ne twork Pro toc ol Da ta Un i t
H F S H igh Freque ncy Syste m
H F S G Human Factor Study Gro u p
H F S N L HF SubNe twor kL ayer
H G A H igh Gain An te n n a
4 6
4 9
I A PA In strument A p proach Procedu res Au tom a t ion
I A P S In tegra ted Avion ics Process i ng Syste m
I A R P Inver se Ad dress Resol u t ion Pro toc ol
IAS In dic a ted Ai r s peed is the speed indic a ted by a
di ffere n t ial press u re airspeed indic a tor th a t
mea s u res the actual press u re di ffere n t ial in the
pi to t - sta t ic hea d. It is the actual instrument
i n dic a t ion for a given fl ight con di t ion .
I ATA In tern a t ional Air Tra n s port Assoc ia t ion
I B AC In tern a t ional Bus i n ess Avia t ion Counc i l
I C ( 1 ) In tegra ted Circui t
( 2 ) In terc a bi n e t
I C AO In tern a t ional Civil Avia t ion Orga n iz a t ion (Mon trea l )
I C C IA PS Card Cage
I C C A I A In tern a t ional Coordi n a t i ng Council of Aeros pace
In dustries
I C D ( 1 ) In sta l la t ion Con trol Drawi ng
( 2 ) In terface Con trol Drawi ng
( 3 ) In teract ive Des ign Center
I C M In terline Com mun ic a t ions Ma nu a l
I C M P In ternet Con trol Message Pro toc ol
I C N I A In tegra ted Com mun ic a t ion s, Naviga t ion and
Id e n t i fic a t ion Avion ic s
I C P In i t ial Confl ict Pro be
I C S S In tegra ted Com mun ic a t ion Swi tch i ng Syste m
I C U In strument Com pa ra tor Un i t
I D Id e n t i fier
I D C In dic a tor Display / C on trol
I d e n t The act ion of the tra n s pon d er tra n s m i t t i ng an extra
p ul se along wi th its id e n t i fic a t ion code (at the request
of a con trol ler ).
I D I In i t ial Domain Id e n t i fier
H S AC E Horizon tal Sta bi l izer Act u a tor Con trol Electron ic s
H S- D S A D H igh Speed Fra me Re lay Service Access Device
H S I Horizon tal Situation In dic a tor. An indic a tor th a t
di s plays bea ri ng, g l id es lo pe, di sta nce, ra dio so u rce,
c o u r se and hea di ng inform a t ion .
H S I T Ha rdwa re and Softwa re In tegra t ion Test
H S L Hea di ng Se lect
H S R H igh Sta bi l i ty Refere nce
H S R P Hot Sta n dby Ro u t i ng Pro toc ol
H S TA Horizon tal Sta bi l izer Trim Act u a tor
H TC H ig h est Two - way Channel
H U D Head-Up Display
H V P S H ig h -Vol tage Power Supply
H W Ha rdwa re
H W C I Ha rdwa re Configu ra t ion Ite m
H X Heat Exch a nger
H Y D Hydraul ic
H Y D I M Hydraul ic In terface Module
H z Hertz (cyc les per sec on d )
I2 S In tegra ted Inform a t ion Syste m
I AC S P In tern a t ional Aeron au t ical Com mun ic a t ions
Service Provid er
I / F In terface
I A 5 In tern a t ional A l p h a bet Num ber 5
I AG S In tegra ted A R INC Gro und Sta t ion
I A N A In ternet Ass ign ed Num ber Au th ori ty
I AOA In dic a ted Ang le - of - At tack
I AO PA In tern a t ional Council of Ai rc raft Own ers and
P i lo ts Assoc ia t ion s
4 8
5 1
I M C In strument Me teorological Con di t ion s
I M G Im ple me n ta t ion Ma n age ment Gro u p
I M I Im bed d ed Message Id e n t i fier
I M O K I’m Ok ay
I M PAT T Im pact Ava la nche and Transmit Ti me. This type of
D i o d e diod e, when moun ted in an appro pria te cavi ty,
produces mic rowave osc i l la t ions and ampl i fic a t ion .
I n Inch
I N B D ( 1 ) Inboa rd
( 2 ) Inbo un d
I N D In dic a tor
I n d i c a t e d The altitude above mean sea level (unc orrected
A l t i t u d e for te m pera t u re ).
I N F O Inform a t ion Fra me
i n . h g. Inch es of Mercu ry
I N I T In i t ia l iz a t ion
I N J In ject ion
I N M A R S AT In tern a t ional Ma ri t i me Sa te l l i te Orga n iz a t ion
I N P H In terp h on e
I N S In ert ial Naviga t ion Syste m . A se l f - c on ta i n ed,
d ea d - reckon i ng system that se n ses the acce lera t ion
a long the th ree axes of the airc raft and calcula tes th e
di sta nce trave led from a refere nce poi n t . Accu racy
of the system dec rea ses wi th res pect to time.
I N S T In strume n t
I N TC In terce p t
I n t e r N I C In ternet Ne twork Inform a t ion Center
I n t r u d e r An altitude re port i ng airc raft that is be i ng con s id ered
as a po te n t ial th reat and processed by the th rea t
d e tect ion logic (TCA S ).
I / O Inp u t / O u tp u t . Refers to bi - di rect ional data ports.
I D G In tegra ted Drive Ge n era tor
I D P In i t ial Domain Pa rt
I D R P In ter- Domain Ro u t i ng Pro toc ol
I D S ( 1 ) Ice De tect ion Syste m
( 2 ) In tegra ted Display Syste m
( 3 ) Inform a t ion Display Syste m
I D U In teract ive Display Un i t
I E C IA PS Envi ronme n tal Con trol Module
I E D In sert ion Extract ion Device
I E E E In st i t u te of Electrical and Electron ic Engi n eer s
I E P R In tegra ted Engine Press u re Ratio
IF (if) In termedia te Freque nc y. A freque ncy to wh ich a
s ignal is shifted as an in-be tween step in the rece p t ion
or tra n s m i ss ion of a sign a l .
I FA L PA In tern a t ional Fed era t ion of Ai rline Pilo ts Assoc ia t ion
I FATC A In tern a t ional Fed era t ion of Air Traffic Con trol ler s’
Assoc ia t ion s
I F E In - Fl ight En terta i nme n t
IFP S In tegra ted In i t ial Fl ight Plan Process i ng Syste m
IFR In strument Fl ight Rules
IFR B In tern a t ional Freque ncy Regi stra t ion Boa rd
I G E S S ta n d a rdized Gra p h ics Exch a nge Fi le
I G I A In terage ncy Group on In tern a t ional Avia t ion
I G V Inlet Guide Va n e
I L M In d e pendent Landi ng Mon i tor
I L S In strument Landi ng Syste m . The system provid es
la tera l ,a long - c o u r se and vert ical guid a nce to airc raft
a t te m p t i ng a la n di ng.
I M A In tegra ted Modular Avion ic s
I M A S In tegra ted Miss ion Avion ics Syste m
5 0
5 3
I S D O S Inform a t ion System Des ign and Optimiz a t ion Syste m
I S H In termedia te Syste m He l lo
I S L N Isola t ion
I S O ( 1 ) In tern a t ional Orga n iz a t ion for Sta n d a rdiz a t ion
( 2 ) In tern a t ional Sta n d a rds Orga n iz a t ion
( 3 ) Isola t ion
I s o-C o n t o u r Refer to con to u r
ISO PA ISO Pro toc ol Arch i tect u re
I S Q C In ter so und Quality Con trol fac i l i ty. Fac i l i ty th a t
ch ecks, la bels and di stri b u tes all vid eo casse t tes.
I S P ( 1 ) In tegra ted Swi tch i ng Pa n e l
( 2 ) In ternet Service Provid er
I S R In terrupt Service Ro u t i n e
I S S N In termedia te System Subnetwor k
I S U In i t ial Signal Un i t
I TA In st i t u te of Air Tra n s port
I T M Inform a t ion Tech n ology Ma n age ment is the gro un d
ba sed port ion of an A DMS (See also EDMS ).
I TO In di um - Tin Oxid e
I T S In tegra ted Test Syste m
I T S E In tegra ted Test and Support Envi ronme n t
I T T ( 1 ) In ter stage Tu r bine Te m pera t u re
( 2 ) In ter- Tu r bine Te m pera t u re
I T U In tern a t ional Te lec om mun ic a t ions Un ion
I U P S In ternal Un i n terru p t i ble Power Supply
I V Isola t ion Va lve
I V S I In sta n ta n eo us Vert ical Speed In dic a tor
I T W S In tegra ted Terminal Wea th er Syste m
J A A Joint Avia t ion Au th ori ty
J A R Joint Ai rworth i n ess Requi re me n t
I O C ( 1 ) In i t ial Opera t ional Capa bi l i ty
( 2 ) Inp u t / O u tput Conce n tra tor
( 3 ) Inp u t / O u tput Con trol ler
I O N In st i t u te of Naviga t ion
I O R In dian Ocean Region
I O S In ternet Opera t i ng Syste m
I OT & E In i t ial Opera t ional Test and Eva l u a t ion
I P ( 1 ) In structor Pilo t
( 2 ) In termedia te Press u re
( 3 ) In ternet Pro toc ol
I PAC G Inform a t ional Pac i fic Air Traffic Con trol
C oordi n a t i ng Gro u p
I P B I l l ustra ted Pa rts Break d own
I P C ( 1 ) I l l ustra ted Pa rts Cata log
( 2 ) In tegra ted Process i ng Cabi n e t
( 3 ) In termedia te Press u re Com pressor
I P D ( 1 ) In dustrial Products Divi s ion
( 2 ) In tegra ted Product De l ivery
I P I In i t ial Pro toc ol Id e n t i fier
I P L I l l ustra ted Pa rts List
I P R In ternet Pro toc ol Ro u ter
I P T In termedia te Press u re Tu r bi n e
I R D In tegra ted Rece iver / Dec od er
I R E In ternal Roll Extrus ion
I R P In tegra ted Refuel Pa n e l
I R S ( 1 ) In ert ial Refere nce Syste m
( 2 ) In terface Requi re me n ts Spec i fic a t ion
I R U In ert ial Refere nce Un i t
I S A ( 1 ) In dustry Sta n d a rd Arch i tect u re
( 2 ) In tern a t ional Sta n d a rd Atm os p h ere
I S C In tegra ted Systems Con trol ler
I S D N In tegra ted Services Digi tal Ne twor k
5 2
5 5
L 5 C ivil Sa te l l i te Freque nc y
LA A S Local Area Augme n ta t ion Syste m
L a b L a bora tory
LA D G P S Local Area Differe n t ial GPS
LA N Local Area Ne twor k
L A P B L i nk Access Pro toc ol - Ba la nced
L AT L a t i t u d e
L- B a n d A ra dio freque ncy band from 390 to 1,550 MHz
L C A L ayered Com ponent Arch i tect u re
L C C Lea dless Chip Carrier
L C D L iquid Crystal Display
L C F L i nk Con trol Fie ld
L C I Logical Channel Id e n t i fier
L C M Logic Con trol Module
L C N Local Com mun ic a t ions Ne twor k
L C P L ig h t i ng Con trol Pa n e l
L C R L i nk Con n ect ion Refusa l
L C S T B Low Cost Simula t ion Test bed
L D Lower Da ta
L D C C Lea d ed Chip Carrier
L D G P S Local Area Differe n t ial Glo bal Pos i t ion i ng Sa te l l i te
L D O C Long Dista nce Opera t ional Con trol
L D U Lamp Driver Un i t
L E L i nk Esta bl i s h
L E D L ight Emitting Diod e
L e g The sect ion of the fl ight be tween two waypoi n ts.
L E O Low Earth Orbi t i ng
J A R-AW O Joint Ai rworth i n ess Requi re me n ts – All Wea th er
O pera t ion s
J ATO Jet Ass i sted Takeoff
J C D P Joint Conceptual Defi n i t ion Phase
J D P Joint Defi n i t ion Phase
J F E T J unct ion Fie ld Effect Tra n s i stor
J P S Jo u rnal Process i ng Syste m
J / S Ja m mer to Signal Ratio
J S AT Joint System Acce p ta nce Test
J TAG Joint Test Act ion Gro u p
J T I D S Joint Tact ical Inform a t ion Distri b u t ion Syste m
K B Ki lo - Bytes (th o usand bytes )
K B I T S Ki lo bi ts
K b p s Ki lo bi ts per sec on d
k b / s Ki lo bi ts Per Sec on d
K B U Key boa rd Un i t
K e y A h a nd-o pera ted swi tch i ng device or the act of
o pera t i ng such a device.
K G Ki logra m
k H z Ki lo h ertz (1000 cyc les per sec on d )
k m Ki lome ter
K P S Ki lo bytes Per Sec on d
k t s Kn o ts
k VA Ki lovol t - a m pere
k W Ki lowa t t
L Left
L 1 L - Band carrier (1575.42 MHz)
L2 L - Band carrier (1227.6 MHz)
5 4
5 7
L o c k-O n The con di t ion that exi sts when the DME rece ives
re ply pul ses to at lea st 50 percent of th e
i n terroga t ion s. Va l id di sta nce inform a t ion is th e n
ava i la ble.
LO M Loc a tor Outer Ma r ker. An NDB that is co-loc a ted at
the sa me site as the 75 MHz outer marker beac on .
LO N Longi t u d e
LO P Line Of Pos i t ion
LO R A N Long Range Naviga t ion . A system us i ng a gro un d
fac i l i ty com posed of a master sta t ion and a slave
sta t ion . The airborne rece iver com p u tes the pos i t ion
of the airc raft by us i ng two or more rece ived
m a ster- s lave pairs of sign a l s. LORA N - A o pera tes at
1850, 1900 and 1950 kHz. LORAN-C opera tes at
100 kHz. LORA N-A was re placed by LORAN-C in
1980.
LORAN C Long Range Naviga t ion Syste m
LO S ( 1 ) Line Of Sig h t
( 2 ) L i n e - O rie n ted Simula t ion
L P L i n ear Pola riz a t ion
LP C Low Press u re Com pressor
L P D U L i nk Pro toc ol Da ta Un i t
LP T Low Press u re Tu r bine
LRA or LRRA ( 1 ) Low - R a nge Radio A l t i me ter
( 2 ) Line Re placea ble Asse m bly
L R C Long Range Crui se
L R M Line Re placea ble Module
L R N Long Range Naviga t ion
L R R Long Range Radar
L R U Line Re placea ble Un i t
L S B ( 1 ) Lower Sid e ba n d. The lower sid e band is th e
di ffere nce in freque ncy be tween the AM carrier
s ignal and the modula t ion sign a l .
( 2 ) Lea st Sign i ficant Bi t
L F Low Freque nc y. The freque ncy ra nge from 30 to
300 kHz.
L F R Low Freque ncy Radio Range
L G A Low Gain An te n n a
L H P L ig h tn i ng HIRF P ro tect ion
LI B Left Inboa rd
L I M L i m i t
L I M N AT R A N L i m i ted North Atla n t ic Regional Air Naviga t ion
L I N C S Long - Haul In terfac i l i ty Com mun ic a t ions Syste m
LI S N Line Im ped a nce Sta bi l iz a t ion Ne twork
L L C Logical Link Con trol
L L M S L iquid Level Mea s u re ment Syste m
L L P Left Lower Pl ug. Id e n t i fies the pl ug on the rea r
c on n ector of an avion ics un i t .
L/ M L i st of Ma teria l s
L M E L i nk Ma n age ment En t i ty
L M I Logical Ma n age ment In terface
L M M Loc a tor Mid dle Ma r ker. An NDB that is co-loc a ted at
the sa me site as the 75 MHz mid dle marker beac on .
L M P Left Mid dle Pl ug. Id e n t i fies the pl ug on the rea r
c on n ector of an avion ics un i t .
L M T Local Mean Ti me
L N A Low Noi se Am pl i fier
LN AV L a teral Naviga t ion
LO Low
LO B Left Outboa rd
LO C Loc a l izer. The la teral guid a nce port ion of an
ILS syste m .
5 6
5 9
M a g n e t i c The di rect ion north as determ i n ed by the ea rth’s
N o r t h m agn e t ic fie ld. The refere nce di rect ion for
mea s u re ment of magn e t ic di rect ion s.
M A I N T Ma i n te n a nce
M A L D T Mean Adm i n i stra t ive and Logi st ics De lay Ti me
M A P ( 1 ) M i ssed A p proach Poi n t
( 2 ) Mode An nunc ia tor Pa n e l
M a r ke r A tra n s m i t ter opera t i ng at 75 MHz that provid es
B e a c o n id e n t i fic a t ion of a pa rt icular pos i t ion along an airway
or on the approach to an instrument runway. T h e
m a r ker beac on is con t i nu o us ly ton e - m odula ted by a
400 - H z , a 1,300-Hz or a 3,000-Hz ton e. Ma r ker
beac ons along an instrument runway provide
a long - c o u r se (ra nge) guid a nce and des ign a te when an
a i rc raft should be at a certain altitude if the airc raft is
fol lowi ng the glid e pa th .
M / A S I Mach / Ai r s peed In dic a tor
M A S P S M i n i mum Avia t ion System Perform a nce Sta n d a rds
M AT Ma i n te n a nce Access Term i n a l
M AW P M i ssed A p proach ed Waypoi n t
M A X Ma xi mum
MAX CLB Ma xi mum engine th rust for two - e ngine climb
MAX CRZ Ma xi mum engine th rust for two - e ngine crui se
M B Ma r ker Beac on
M B E Mul t i ple Bit Error
M b p s Mega bytes per Sec on d
M C Ma ster Change
M C A M i n i mum Cross i ng A l t i t u d e
M C B M ic rowave Circuit Boa rd
M C B F Mean Cyc les Be tween Fa i l u res
M C C Ma i n te n a nce Con trol Com p u ter
M C D P Ma i n te n a nce Con trol Display Pa n e l
L S D Lea st Sign i ficant Digi t
L S- D S A D Low - S peed Fra me Re lay Service Access Device
L S- F R A D Low - S peed Fra me Re lay Access Device
L S I L a rge Sc a le In tegra t ion
L S K Line Se lect Key
L S N Local Subnetwor k
L S P L i nk Sta te PDU
LTC Lowest Two - way Channel
LT P Left Top Pl ug. Id e n t i fies the pl ug on the rea r
c on n ector of an avion ics un i t .
Lubber Line A fi xed line placed on an indic a tor to indic a te th e
fron t - to - rear axis of the airc raft .
LV Lower Sid e band Voice
LV D T ( 1 ) L i n ear Va ria ble Differe n t ial Tra n sformer
( 2 ) L i n ear Vol tage Differe n t ial Tra n sducer (used wi th
a i rc raft con trol surface servos ).
LV L C H G Level Change
LV P S Low Vol tage Power Supply
LV TO Low Vi s i bi l i ty Take - Off
M Mach Num ber
m Me ter
M A A Ma xi mum Au th orized IFR A l t i t u d e
M AC Medi um Access Con trol ler
M a c h Mach num ber is the ra t io of the true airspeed to th e
N u m b e r s peed of so und at a pa rt icular fl ight con di t ion . It is
the ch ief cri terion of airflow pa t tern and is us u a l ly
re prese n ted by the free - stream stea dy - sta te va l ue.
M a g Magn e t ic
M a g n e t i c The bea ri ng wi th res pect to magn e t ic north .
B e a r i n g
5 8
6 1
M F M Ma i n te n a nce Fault Me m ory
M F S Media Fi le Server
M G S C U Main Gear Steeri ng Con trol Un i t
M H D Magn e t ic Ha rd Drive
M H z Megah ertz (1,000,000 cyc les per sec on d )
M I B Ma n age ment Inform a t ion Ba se
MIB II Ma n age ment Inform a t ion Ba se II
M I C M ic ro p h on e. A l so refers to the output signal of
the mic ro p h on e.
M i c r o E A R T S M ic ro En ro u te Au tom a ted Radar Tracki ng Syste m
M I D U Mul t i p u rpose In teract ive Display Un i t
M I L M i l i ta ry
M I L- H D B K- 2 1 7Ge n eral Predict ion of Electron ic Equi pment (MTBF )
M ILS P E C M i l i ta ry Spec i fic a t ion s
M I L-S T D- 8 8 2 System Safe ty Requi re me n ts
M i n ( 1 ) M i n i mum
( 2 ) M i nu tes
M I P S M i l l ion In struct ions Per Sec on d
M K R ( 1 ) Ma r ker
( 2 ) Ma r ker Beac on
M L A Ma n e uver Limited A l t i t u d e
M L S M ic rowave Landi ng Syste m
M LW Ma xi mum Landi ng We ig h t
M M Ma ss Me m ory
M M E Modular Mo un t i ng Enc los u re
M M I Ma n - Machine In terface
M M I C Mon ol i th ic Mic rowave In tegra ted Circui t
M m o The maxi mum Mach num ber at wh ich an airc raft
has been cert i fied to opera te.
M C D U Mul t i funct ional Con trol Display Un i t
M C N Ma nu fact u ri ng Con trol Num ber
M C P ( 1 ) Ma i n te n a nce Con trol Panel
( 2 ) Mode Con trol Pa n e l
M C T Max Con t i nu o us T h rust
M C U ( 1 ) Modular Concept Unit (approxi m a te ly 1/ 8 - AT R,
Ai rline Tra n s port Rack )
( 2 ) Mo tor Con trol Unit (used in au to th ro t tle )
( 3 ) Mul t i funct ion Concept Un i t
M DA M i n i mum Descent A l t i t u d e
M D C Ma i n te n a nce Diagn ost ic Com p u ter
M D C R S Me teorological Da ta Col lect ion and Re port i ng Service
M D L Mul t i p u rpose Da ta Link
M D S M i n i mum Discern i ble Sign a l . The MDS is the lowest
RF signal level that can be detected as a va l id sign a l .
M D T Ma i n te n a nce Display Term i n a l
M E A M i n i mum En ro u te A l t i t u d e
M E C Main Equi pment Center
M E L M i n i mum Equi pment List . The list of equi pment th a t
the FA A requi res be aboa rd and wor ki ng on an
a i rc raft before flyi ng.
M E O Medi um Earth Orbi t
M E S Main Engine Sta rt
M E T Me teorology
M F Medi um Freque nc y. The port ion of the ra dio
s pectrum from 300 kHz to 3 MHz.
M F C P Mul t i funct ion Con trol Display Pa n e l
M F D Mul t i funct ion Display
M F D S Mul t i funct ion Display Syste m
M F D U Mul t i funct ion Display Un i t
M F I T Mean Fault Isola t ion Ti me
6 0
6 3
M P E L Ma xi mum Perm i ss i ble Expos u re Leve l
M P U Mul t i funct ion Process Un i t
M R A M i n i mum Rece p t ion A l t i t u d e
MRDU Mul t ichannel Rece iver / Dec od er Un i t
M R O S E Mul t i ple - ta s ki ng Rea l - t i me Opera t i ng Syste m
E xecu t ive
M R R Ma nu fact u ri ng Revi s ion Request
M R T Mean Res pon se Ti me
M S M i l l i sec on d
m / s Me ter per Sec on d
M S A S M i n i stry of Tra n s porta t ion Sa te l l i te
Augme n ta t ion Syste m
M S B Most Sign i ficant Bi t
M S C Message Seque nce Chart
M S C P Mo bi le Sa te l l i te Service Provid er
M S D ( 1 ) Ma ss Storage Device
( 2 ) Most Sign i ficant Digi t
M S G Message
M S I Medi um Sc a le In tegra t ion
M S K M i n i mum Shift Keyi ng
M S L Mean Sea Leve l
M -S N D C F Mo bi le - Subnetwork De pendent Converge nce
M S P Mode S Spec i fic Pro toc ol
M S S R Mon o p ul se Sec on d a ry Surve i l la nce Radar
M S S S Mode S Spec i fic Services
M S U Mode Se lect Un i t
M T M i n i mum Ti me
M M R Mul t i - Mode Rece iver
M M S Ma i n te n a nce Ma n age ment Syste m
M N Magn e t ic North
M N C I D Ne twork Ma n age ment Category In teract ion Diagra m
M N P S M i n i mum Naviga t ion Perform a nce Spec i fic a t ion
M O Magn e to - O p t ic a l
M OA ( 1 ) Me m ora n dum of Agree me n t
( 2 ) M i l i ta ry Opera t ion Area
M O C A M i n i mum Obstruct ion Clea ra nce A l t i t u d e
M O D ( 1 ) Magn e to - O p t ical Drive
( 2 ) Modi fic a t ion
( 3 ) Modula tor
Mode A The pul se format for an id e n t i fic a t ion cod e
i n terroga t ion of an ATC RBS tra n s pon d er.
Mode B An optional mode for tra n s pon d er interroga t ion .
Mode C The pul se format for an altitude inform a t ion
i n terroga t ion of an ATC RBS tra n s pon d er.
Mode D An un a ss ign ed, o p t ional tra n s pon d er mod e.
Mode S ( 1 ) Mode Se lect (a tra n s pon d er format to allow
di sc re te interroga t ion and data link capa bi l i ty )
( 2 ) Se lect ive interroga t ion mode of SSR
M O D E M Modula tor / De m odula tor
M O P R M i n i mum Opera t ional Perform a nce Requi re me n ts
M O P S M i n i mum Opera t ional Perform a nce Sta n d a rds
M O R A M i n i mum Off - Ro u te A l t i t u d e
M O S Me tal Oxide Se m ic on ductor
M O S F E T Me tal Oxide Se m ic on ductor Fie ld Effect Tra n s m i t ter
M O U Me m ora n dum Of Un d er sta n di ng
M P ( 1 ) Main Processor
( 2 ) M id dle Pl ug. Id e n t i fies the pl ug pos i t ion on th e
rear con n ector of an avion ics un i t .
M P C U Mul t i port Pro toc ol Converter Un i t
6 2
6 5
M T T M A Mean Ti me to Ma i n te n a nce A lert
M T T R Mean Ti me To Re pa i r. A perform a nce figu re calcula ted
by dividi ng the sum of the act ive re pair ela psed times
acc rued in a period on a num ber of des ign a ted items by
the num ber of th ese items re pa i red in the sa me period.
M T T R S Mean Ti me To Restore Service
M T T U R Mean Ti me To Un sch eduled Re m ova l . A perform a nce
figu re calcula ted by dividi ng the sum m a t ion of times
to un sch eduled re m oval for a sa m ple of re m oved
i tems by the num ber of re m oved items in the sa m ple.
This is di fferent from MTBUR since no allowa nce is
given to items that have not been re m oved.
M U ACA RS Ma n age ment Un i t
M U LT Mul t i pl ier
M U S M i n i mum Use Spec i fic a t ion . A ge n eric desc ri p t ion by
pa ra me ter and ch a racteri st ics of the test equi pme n t
and reso u rces requi red for test i ng a unit or syste m .
M U X Mul t i plexer
M WA R A Ma j or World Air Ro u te Area
N North
N 1 Fan speed
N 2 In termedia te com pressor speed
N3 H igh speed com pressor
N / A Not A p pl ic a ble
N AC A Na t ional Advi sory Com m i t tee for Aeron au t ic s
N A D I N Na t ional Ai r s pace Da ta In terch a nge Ne twor k
N A K Nega t ive Ackn owledge me n t
N A S ( 1 ) Na t ional Ai rc raft Sta n d a rd
( 2 ) Na t ional Ai r s pace Syste m
N A S A Na t ional Aeron au t ics and Space Adm i n i stra t ion
N A S PA L S NAS Prec i s ion A p proach and Landi ng Syste m
N AT North Atla n t ic Tracks
M T B F Mean Ti me Be tween Fa i l u res. A perform a nce figu re
c a lcula ted by dividi ng the to tal unit flyi ng hours
( a i r borne) acc rued in a period of time by the num ber
of unit fa i l u res that occu rred du ri ng the sa me time.
W h ere to tal unit hours are ava i la ble, this may be used
in lieu of to tal unit flyi ng hours.
M T B O Mean Ti me Be twee n O u tages
M T B R ( 1 ) Mean Ti me Be tween Re m ova l
( 2 ) Mean Ti me Be tween Re pa i r s. A perform a nce
figu re calcula ted by dividi ng the to tal unit flyi ng
hours acc rued in a period by the num ber of un i t
re m ovals (sch eduled pl us un sch eduled) th a t
occu rred du ri ng the sa me period.
M T B U R ( 1 ) Mean Ti me Be tween Un sch eduled Re m ova l
( 2 ) Mean Ti me Be tween Unit Re place me n ts. A
perform a nce figu re calcula ted by dividi ng th e
to tal unit flyi ng hours (airborne) acc rued in a
period by the num ber of un sch eduled un i t
re m ovals that occu rred du ri ng the sa me period.
M TC Ma i n te n a nce Terminal Cabi n e t
M T D Ma i n te n a nce Terminal Display
M T F Ma i n te n a nce Terminal Funct ion
M T I Movi ng Ta rget In dic a tor. This type of radar di s play
will show only movi ng ta rge ts.
M T M Module Test and Ma i n te n a nce
M T M I U Module Test and Ma i n te n a nce Bus In terface Un i t
M T S AT Mul t i funct ion Tra n s port Sa te l l i te System (Ja pa n )
M T T DA Mean Ti me To Dispa tch A lert
M T T F Mean Ti me To Fa i l u re. A perform a nce figu re
c a lcula ted by dividi ng the sum m a t ion of times to
fa i l u re for a sa m ple of fa i led items by the num ber of
fa i led items in the sa m ple. The sa me item fa i l i ng N
t i mes con st i t u tes N fa i led items in the sa m ple. This is
di fferent from mean time be tween fa i l u res since no
a l lowa nce is given to items that have not fa i led.
M T T M Mean Ti me To Ma i n te n a nce. The ari thme t ic mean of
the time intervals be tween mainte n a nce act ion s.
6 4
6 7
N E G Nega t ive
N E M A Na t ional Electrical Ma nu fact u rers Assoc ia t ion
N E S D I S Na t ional Envi ronme n tal Sa te l l i te, Da ta and
Inform a t ion Service
N E T Ne twork En t i ty Ti tle
N E XC O M Next Ge n era t ion Com mun ic a t ion s
N E X R A D Next Ge n era t ion Radar
N F F No Faul ts Fo un d
N G AT M New Ge n era t ion Air Traffic Ma n ager
N H H igh Press u re Gas Ge n era tor RPM
N H E No tes and He l ps Edi tor
N I C E NAT Im ple me n ta t ion Ma n age ment Gro u p
C ost Effect ive n ess
N I M S NAS Infra struct u re Ma n age ment Syste m
N I P Ne twork In terface Processor
N I R Ne twork In terface Ro u ter
N I R V Ne twork interface Ro u ter V DL
N I S No t - In - Service
N I S T Na t ional In st i t u te of Sta n d a rds and Tech n ology
N - L a y e r N is set for any layer name (such as link, n e twor k, e tc.)
or for the initial (e. g. N - SDU means LSDU at the link
layer ). OSI model defi n i t ion .
N L Low - P ress u re Gas Ge n era tor RPM
N L M Ne twor k - Loa d a ble Module
N L P Ne twor k L ayer Pro toc ol
N L R Ne th erla n ds Na t ional Aeros pace Labora tory
NLT Not Less T h a n
NM or NMI Nau t ical Mile
N M Ne twor k Ma n age me n t
N ATA Na t ional Air Tra n s port Assoc ia t ion , Inc.
N ATC A Na t ional Air Traffic Con trol lers Assoc ia t ion
N AT S North Atla n t ic Track Syste m
N AT / N A M / PACNorth Atla n t ic / North Americ a n / Pac i fic
N AV Naviga t ion
N AVA I D Naviga t ional Aid
N a v i g a t i o n A medi um holdi ng the custom ized naviga t ion
D a t a c a r d d a ta ba se.
N AV S TA R The NAVSTAR glo bal pos i t ion i ng system (GPS) is a
system us i ng 24 sa te l l i tes, all re port i ng prec i se time
s ign a l s, a long wi th loc a t ion keys. Eight sa te l l i tes are in
each of th ree 63 - d egree inc l i n ed plane circular or bi ts
at 11,000 nmi in altitude. The system is used for
n aviga t ion and determ i n i ng exact pos i t ion .
Nautical Mile E quiva lent to 6,076.1 fee t , or approxi m a te ly 1.15
( n m i ) sta t u te miles.
N B A A Na t ional Bus i n ess Avia t ion Assoc ia t ion
N C N umerical Con trol
N I C New In sta l la t ion Conce p t
N C D No Com p u ted Da ta
N C I Not Curre n tly Im ple me n ted
N C S Ne twork Coordi n a t ion Sta t ion
N D Naviga t ion Display. An EFIS prese n ta t ion subst i t u t i ng
for the horizon tal situation indic a tor (HSI ).
N D B ( 1 ) Naviga t ion Da ta Ba se (as stored in FMC me m ory )
( 2 ) Non - D i rect ional Radio Beac on . A gro und sta t ion
d es ign ed spec i fic a l ly for A DF use that opera tes in
the 190 - to - 550-kHz ra nge.Tra n s m i ts a con t i nu o us
c a rrier wi th eith er 400 - or-1020 Hz modula t ion
( keyed) to provide id e n t i fic a t ion.
N D I Non d eve lo pme n tal Ite m
N E Ne twork Ele me n t
N E A N North Euro pean A DS-B Ne twor k
6 6
6 9
N S Ne twork Service
N S A P Ne twork Service Access Poi n t
N S D U Ne twork Service Da ta Un i t
N S E U Ne u tron Sing le Event Upse t
N S S L Na t ional Severe Storms Labora tory
N T F No Tro u ble Fo un d. ( Referri ng to test i ng or ch eckout of
un i t / m odule.)
N T I A Na t ional Te lec om mun ic a t ions and Inform a t ion
Adm i n i stra t ion (U. S.)
N T S B Na t ional Tra n s porta t ion Safe ty Boa rd
N U I Ne twork User Id e n t i fic a t ion
N V M Non -Vola t i le Me m ory
N V R A M Non -Vola t i le RA M
N W S Na t ional Wea th er Service. The NWS provid es a
gro un d - ba sed wea th er radar network th ro ughout th e
Un i ted Sta tes. The radar network opera tes
c on t i nu o us ly and tra n s m i ts the data to the Na t ion a l
Me teorological Center, wh ere it corre la tes wi th oth er
wea th er observa t ion s.
OAC Ocea n ic Area Con trol Center
OAG Offic ial Ai rline Guid e
OA S Ocea n ic Au tom a t ion Syste m
OAT ( 1 ) O pera t ional Acce p ta nce Test
( 2 ) O p t ional Auxi l ia ry Term i n a l . The OAT m ay be in
the form of a CRT / Key boa rd device capa ble of
i n terfac i ng wi th oth er so u rces of data on th e
a i rc raft and supplyi ng data to a hard copy pri n ter.
( Used in an ACA RS syste m .)
( 3 ) O u ts ide Air Te m pera t u re. The unc orrected
rea di ng of the outs ide te m pera t u re gauge.
D i fferent types of gauges requi re di fferent
c orrect ion factors to obtain sta t ic air te m pera t u re.
OAT S O r bit and Attitude Tracki ng
O B P O pera t ional Bui ld Pla n
N M C Na t ional Me teorological Center
N M C C D Ne twork Ma n age ment Category Cla ss Diagra m
N M C D Ne twork manage ment Category Diagra m
N M F Ne twork Ma n age ment Funct ion
N M I R S Ne twork Ma n age ment In terface Requi re me n ts
S pec i fic a t ion
N M O S N - type Me tal Oxide Se m ic on ductor
N M P Ne twork Ma n age ment Pla n
N M S Ne twor k Ma n age ment Syste m
N M T Not More T h a n
N OA A Na t ional Ocea n ic and Atm os p h eric Adm i n i stra t ion
N O C No t ice Of Change
N O C A R North Atla n t ic Ocea n ic Concept and Requi re me n ts
N O C C Na t ional Opera t ions Con trol Center
NO COM No Com mun ic a t ion . A NO COM annunc ia t ion
i n dic a tes that a downl i nk message has not bee n
ackn owledged in an ACA RS syste m .
N O I No t ice of In qui ry
N o i s e Un d es i red ra n d om electrom agn e t ic di st u r ba nces or
s p u rio us signals that are not pa rt of the tra n s m i t ted or
rece ived sign a l .
N O PAC North Pac i fic
N OTA M No t ice to Ai rme n
N OT U S No t ice to Users (ARINC )
N PA Non - P rec i s ion A p proach
N P D U Ne twork Pro toc ol Da ta Un i t
N R Ne twor k Ro u ter
N R D Ne twork Ro u t i ng Dom a i n
N R P Na t ional Ro u te Progra m
N R Z Non - Re t u rn to Zero
6 8
7 1
O M E G A A n aviga t ion system that uses two hig h - powered
tra n s m i t ter gro und sta t ions to broa d c a st a con t i nu o us
wave sign a l . The rece iver mea s u res the ra nge
di ffere nce be tween the two sta t ions to determ i n e
pos i t ion .
O m n i b e a r i n gThe bearing indicated by a navigational receiver on
transmissions from an omnidirectional radio range
(VOR).
O M S ( 1 ) O nboa rd Ma i n te n a nce Syste m
( 2 ) O rd er Ma n age ment Syste m
O M T Object Mod e l i ng Tech n ique
O OA Object Orie n ted An a lys i s
O O D Object Orie n ted Des ign
O O O I OUT - OFF- ON - IN. An OOOI event is rec ord ed as pa rt
of the ACA RS opera t ion . The OUT event is rec ord ed
when the airc raft is clear of the ga te and rea dy to ta xi .
The OFF event occurs when the airc raft has lifted off
the runway. The ON event occurs when the airc raft
has la n d ed. The IN event occurs when the airc raft has
ta xied to the ramp area .
O n - B l o c kT i m e The time that the airc raft arrives at the ga te.
O P O pera t ion a l
O P T O p t i mum
O PA S O verh ead Panel A R INC 629 Syste m
O P B C O verh ead Panel Bus Con trol ler
O P E R O pera t ion
O P R O nce Per Revol u t ion
O P S O pera t ions Per Sec on d
O P S P E C S O pera t ional Spec i fic a t ion s
O P U O ver s peed Pro tect ion Un i t
O-Q A R O p t ical Quick Access Rec ord er
O R O pera t ional Requi re me n ts
O S O pera t i ng Syste m
O B S ( 1 ) O m n i bea ri ng Se lector. A panel instrument that
c on tains the con trols and circui ts to se lect an
om n i bea ri ng and determine the TO - F ROM
i n dic a t ion .
( 2 ) O p t ical Bypa ss Swi tch
O C A Ocea n ic Con trol Area
O C C O pera t ions Con trol Center
O C D Ocea n ic Clea ra nce De l ivery
O C I G Ocea n ic Com mun ic a t ions Im prove ment Gro u p
O C P Ocea n ic Clea ra nce Processor
O c t a l Ba se-8 coun t i ng syste m . N um bers include 0, 1, 2, 3, 4,
5, 6, 7.
O DA P S Ocea n ic Display And Pla n n i ng Syste m . Will prese n t
ocea n ic fl ight data to con trol lers in a di s play that wi l l
e n a ble be t ter ro u te and altitude ass ignme n ts.
O D I D O pera t ional Display and Input Deve lo pme n t
O D L O p t ical Da ta Link
O E M O riginal Equi pment Ma nu fact u rer
O E U O verh ead Electron ics Un i ts
O f f - B l o c k T i m e The time that the airc raft leaves the ga te.
O F P O pera t ional Fl ight Progra m
O G E O pera t ional Gro und Equi pme n t
O H U O verh ead Unit (HUD)
O I D O u tline In sta l la t ion Drawi ng
O I U O rie n ta t ion / In troduct ion Un i t
O L A N O nboa rd Local Area Ne twor k
O L D I On-Line Da ta In terch a nge
O & M O pera t i ng and Ma i n te n a nce
O M O u ter Ma r ker
O M D O nboa rd Ma i n te n a nce Docume n ta t ion
7 0
7 3
PA N S-O P S P rocedu res for Air Naviga t ion Services - Ai rc raft
O pera t ion s
PA P I P rec i s ion A p proach Pa th In dic a tor s
PA R P rec i s ion A p proach Radar. An X-band radar that
scans a limited area and is pa rt of the
gro un d - c on trol led approach syste m .
PA S Pa sse nger Ad dress Syste m
PAT P i lot A p pl ic a t ions Term i n a l
PAU Pa sse nger Ad dress Un i t
PAW E S Perform a nce Assess ment and Wor kload Eva l u a t ion
PA X Pa sse nger
P B D Place Bea ri ng / D i sta nce (waypoi n t )
P B I D Post Burn - In Da ta
P B X P riva te Bra nch Exch a nge
P C ( 1 ) Per sonal Com p u ter
( 2 ) P ri n ted Circui t
P-C o d e The GPS prec i s ion cod e
P C A P hys ical Configu ra t ion Au di t
P C B P ri n ted Circuit Boa rd
P C C P i lot Con trol ler Com mun ic a t ion
PCI P ro toc ol Con trol Inform a t ion . The N-PCI is
exch a nged be tween peer network me m bers
( OSI Model) to coordi n a te joint inform a t ion .
PCIP P rec i pi ta t ion
P C M P ul se Code Modula t ion
P C M C I A Per sonal Com p u ter Me m ory Card In terface
Assoc ia t ion
P C U ( 1 ) Pa sse nger Con trol Un i t
( 2 ) Power Con trol Un i t
P D P rofi le Desce n t
P DA P re m a t u re Descent A lert
O S C O rd er Sta t us Re port
O S D S Ocea n ic System Deve lo pment Support
O S I ( 1 ) O pen Systems In terc on n ect ion
( 2 ) O pen System In terface
O S I E OSI Envi ronme n t
O S I - R M O pen Systems In terc on n ect ion Refere nce Mod e l
O S P F O pen Shortest Pa th Fi r st
OT & E O pera t ional Test and Eva l u a t ion
OTA Office of Tech n ology Assess ment (U. S.)
OT F P O pera t ional Traffic Flow Pla n n i ng
OT H O ver The Horizon
OT P Office of Te lec om mun ic a t ions Pol icy (U. S.)
OT S Off - T h e - S h e l f
OV R D O verrid e
OV S O verh ead Vid eo Syste m
ox y Oxyge n
PA ( 1 ) Pa sse nger Ad dress
( 2 ) Power Am pl i fier
PAC Pa th At te nu a t ion Com pe n sa t ion
PA / C I Pa sse nger Ad dress / C a bin In terp h on e
PAC I S Pa sse nger Ad dress and Com mun ic a t ion In terp h on e
Syste m
PA D Packet Asse m bler- D i sa sse m bler
Pa i r e d DME channels are pa i red wi th a VORTAC or ILS
C h a n n e l s freque ncy and are au tom a t ic a l ly se lected when th e
VORTAC or ILS freque ncy is se lected. Most naviga t ion
c on trols have this fea t u re.
PA L P rogra m m a ble Array Logic
PA M P ul se Am plitude Modula t ion
7 2
7 5
P E T Pac i fic Engi n eeri ng Tria l s
P E TA L P re l i m i n a ry Euroc on trol Test of Ai r / G ro und Da ta Link
P E TAL II P re l i m i n a ry Euroc on trol Test of Ai r / G ro und Da ta
L i nk, P h a se II
P E TAL IIe P re l i m i n a ry Euroc on trol Test of Ai r / G ro und Da ta
L i nk, P h a se II E xte n s ion
P F ( 1 ) P i lot Flyi ng
( 2 ) Power Factor
P F C P ri m a ry Fl ight Com p u ter
P F C S P ri m a ry Fl ight Con trol Syste m
P F D ( 1 ) P ri m a ry Fl ight Director
( 2 ) P ri m a ry Fl ight Display. An EFIS prese n ta t ion
s u bst i t u t i ng for the A DI.
P F I S Pa sse nger Fl ight Inform a t ion Syste m
P F R P ul se Re pe t i t ion Freque nc y. The ra te at wh ich pul ses
a re tra n s m i t ted.
P F S P roduct Fi le Se ts
P G A Pin Grid Array
P H A R E P rogram for Ha rm on ized ATC Resea rch in Euro pe
P H I B U F Perform a nce Buffet Limit
P H I N O M Nominal Ba nk Ang le
P H Y P hys ical In terface Device
Phase A s ignal in wh ich the phase va ries (wi th res pect to th e
M o d u l a t i o n original signal) wi th the amplitude of the modula tory
s ign a l , wh i le the amplitude of the carrier wave
remains con sta n t . S i m i lar to a modi fied freque nc y
m odula ted sign a l .
P I Pa ra me ter Id e n t i fier
P I A Perform a nce In tegri ty and Ava i la bi l i ty
P I C S P ro toc ol Im ple me n ta t ion Conform a nce Sta te me n ts
P D B Perform a nce Da ta Ba se
P D C P re - De pa rt u re Clea ra nce
P D C U Panel Da ta Conce n tra tor Un i t
P D D Pack age Des ign Docume n t
P D D I P roduct Defi n i t ion Da ta In terface. S ta n d a rdizes digi ta l
d esc ri p t ions of pa rt configu ra t ions and pro pert ies
n eed ed for manu fact u ri ng.
P D F P ri m a ry Display Funct ion
P D L P rogram Des ign Langu age
P- D M E P rec i s ion Dista nce Mea s u ri ng Equi pme n t
P D N P u bl ic Da ta Ne twork (CC ITT / ISD )
P D O P Pos i t ion Dilution Of Prec i s ion . A G PS term for error
i n troduced into the GPS calcula t ion s.
P D O S Powered Door Ope n i ng Syste m
P D R P re l i m i n a ry Des ign Review
P D S P ri m a ry Display Syste m
P D U ( 1 ) Power Distri b u t ion Un i t
( 2 ) Power Drive Un i t
( 3 ) P ro toc ol Da ta Un i t . The N-PDU is a com bi n a t ion
of the N-PCI and the N-UD or N-SDU. The
N - PDU is the to tal inform a t ion that is tra n sferred
be tween peer network me m bers (OSI Model)
as a un i t .
P E C T Peer En t i ty Con tact Ta ble
P E P Peak Enve lo pe Power
P E R F Perform a nce
Performance A re la t ive num ber used to com pa re the perform a nce
I n d ex of di fferent radar syste m s. It is calcula ted from
tra n s m i t ter peak power, a n tenna ga i n , p ul se width , prf,
a n tenna beam width and the rece iver noi se figu re.
P E R T P rogram Eva l u a t ion Review Tech i n que
P E S Pa sse nger En terta i nment Syste m
7 4
7 7
P N F P i lot Not Flyi ng
P N R Point of No Re t u rn
P OA Plain Old ACA RS
P O C P roof Of Conce p t
Polled Mode An ACA RS mode of opera t ion in wh ich the airborn e
system tra n s m i ts only in res pon se to rece ived upl i nk
messages (pol l s ).
P O P Point of Prese nce
P O R Pac i fic Ocean Region
P O S Pos i t ion
POS INIT Pos i t ion In i t ia l iz a t ion
POS REF Pos i t ion Refere nce
P OT Po te n t iome ter
P OT S Plain Old Te le p h one Syste m / Service
P P D U P hys ical Layer Pro toc ol Da ta Un i t
P P I Pla n n ed Pos i t ion In dic a tor. A type of radar di s play
wh ich shows airc raft pos i t ions and airways ch a rt on
the sa me di s play.
P P L P rocessor- to - P rocessor Link
p p m pages per minu te
P P M ( 1 ) P ul se Pos i t ion Modula t ion
( 2 ) Pa rts Per Million
P P O S P resent Pos i t ion
P P P Poi n t - to - Point Pro toc ol
P P S ( 1 ) Packe ts Per Sec on d
( 2 ) P rec i se Pos i t ion i ng Service
( 3 ) P ul se Per Sec on d
P R A I M P redict ive Rece iver Au ton om o us In tegri ty Mon i tori ng
P R A M P rerec ord ed An n o unce ment Mach i n e
P R E L I M P re l i m i n a ry Da ta
P I D ( 1 ) Pa ra me ter Id e n t i fier
( 2 ) P ri m i t ive Id e n t i fier
( 3 ) P rocess Id e n t i fier
P I / O P rocessor Inp u t / O u tp u t
P I R E P roduct ion or Pipe In ternal Roll Extrus ion
P I R E P S P i lot Re ports
Pitot Pressure The sum of the sta t ic and dyn a m ic press u res and is
the to tal force per unit area exerted by the air on th e
s u rface of a body in motion .
Pitot Tu b e A forwa rd fac i ng pro be attach ed to the outs ide of th e
a i rc raft to se n se the re la t ive press u re of the airc raft
m ovi ng th ro ugh the atm os p h ere. Na med for He n ri
P i tot who fi r st used this me th od of mea s u ri ng fl uid
flow press u re.
P L Pa ra me ter Le ng th
PLA ( 1 ) Power Level Ang le
( 2 ) P rogra m m a ble Logic Array
P L G R P rec i s ion Lig h twe ight GPS Rece iver
P L L P h a se Locked Loo p
P M P h a se Modula t ion
P M A ( 1 ) Pa rts Ma nu fact u ri ng A p prova l
( 2 ) Permanent Magnet A l tern a tor
P M AT Porta ble Ma i n te n a nce Access Term i n a l
P M C P rovi s ional Me m ory Cover
P M G Permanent Magnet Ge n era tor
P M O S P - Type Me tal Oxide Se m ic on ductor
P M S Perform a nce Ma n age ment Syste m
P N ( 1 ) Pa rt Num ber
( 2 ) Pseudo Noi se
P N C S Perform a nce Naviga t ion Com p u ter Syste m
P N D P ri m a ry Naviga t ion Display
P N E U P n e um a t ic
7 6
7 9
P S E U P roxi m i ty Se n sor Electron ic Un i t
P S L / P S A P ro blem Sta te ment Langu age / P ro blem Sta te me n t
An a lyzer
P S M Power Supply Modules
P S N Packet Swi tch i ng Ne twor k
P S P L P referred Sta n d a rd Pa rts List
P S R P ri m a ry Surve i l la nce Radar. The pa rt of the ATC
system that determ i n es the ra nge and azi mu th of an
a i rc raft in a con trol led air space.
P S S P roxi m i ty Se n sor Syste m
P S U Pa sse nger Service Un i t
P T To tal Press u re
P T D Perform a nce Test Dom a i n
P S E Packet Swi tch i ng Exch a nge
P S T N P u bl ic Swi tch ed Te le p h one Ne twor k
P T H Pa th
P T I Packet Type Id e n t i fier
P T M Peri p h eral Tra n s i t ion Module (I/O interface for SBC )
P T R P roduct ion Test Requi re me n ts
P T S P ro blem Tracki ng Syste m
P T S D P roduct ion Test Spec i fic a t ion Docume n t
P T T ( 1 ) Post , Te le p h one and Te legra p h
( 2 ) P ush To Ta l k. A l so refers to the swi tch i ng sign a l
that enables the tra n s m i t ter.
( 3 ) P ush To Test
P T U Power Tra n sfer Un i t
P V D Plan View Display
P V Pa ra me ter Va l ue
P V C Permanent Vi rtual Circui t
P V T Pos i t ion , Ve loc i ty, Ti me
P R E S S P ress u re
P r e s s u r e The altitude mea s u red above sta n d a rd press u re leve l .
A l t i t u d e Ba sed on the re la t ionship of press u re and altitude
wi th res pect to a sta n d a rd atm os p h ere.
P R E V P revio us
P r e v e n t i v e A resol u t ion advi sory that instructs the pi lot to avoid
A d v i s o r y certain devia t ions from cu rrent vert ical ra te. ( TCA S )
P R F P ul se Re pe t i t ion Freque ncy
P R I ( 1 ) P ri m a ry
( 2 ) P ri m a ry Rate In terface
P R M ( 1 ) P rec i s ion Runway Mon i tori ng
( 2 ) P ro posed Rule Maki ng
P R N Pseudo Random Noi se
P R O C P rocedu re
P R O F P rofi le
P R O G P rogress Page on MC DU
P R O M P rogra m m a ble ROM
P R- N AV P rec i s ion Area Naviga t ion
P r o t o c o l A set of rules for the format and con tent of messages
be tween com mun ic a t i ng processes.
P R OV P rovi s ion a l
P R OX P roxi m i ty
P R S OV P ress u re Regula t i ng and Shutoff Va lve
P / R S T P ress To Rese t
P R T R P ri n ter
P S Power Supply
P S A Power Supply Asse m bly
P S A S P ri m a ry Sta bi l i ty Augme n ta t ion Syste m
P S D Port Shari ng Device
P S D N Packet Swi tch ed Da ta Ne twor k
7 8
8 1
R A A Regional Ai rline Assoc ia t ion
Rabbit Tr a c k s R a b bit Tracks, or run n i ng ra b bi ts, refer to th e
di st i nct ive di s play produced by anoth er (alien ra d a r )
radar system tra n s m i ss ion .
R A D ( 1 ) R a dia l
( 2 ) R a dio
( 3 ) R a pid A p pl ic a t ion Deve lo pme n t
R a d a r R a dio De tect i ng and Rangi ng. A system that mea s u res
di sta nce and bea ri ng to an object .
Radar Mile The time interval (approxi m a te ly 12.359 mic rosec on ds )
requi red for ra dio waves to travel one nau t ical mile
and re t u rn (to tal of 2 nm i ).
R a d i a l A line of di rect ion goi ng out from a VOR sta t ion
mea s u red as a bea ri ng wi th res pect to magn e t ic
n orth .
R a d o m e The ra d ome is the pro tect ive cover on the airc raft
n ose that fi ts over the wea th er radar system ante n n a .
The ra d ome is tra n s pa rent at radar freque nc ies.
R A F Requi re me n ts An a lysis Fold er
R A I R a dio A l t i me ter In dic a tor
R A I M Rece iver Au ton om o us In tegri ty Mon i tori ng
R A LT R a dio A l t i me ter (also RA , RA DA LT, LRA , LR RA )
R A M R a n d om Access Me m ory. Ge n era l ly used to desc ri be
rea d / wri te integra ted circuit me m ory.
R A P P S Re m o te Area Prec i s ion Pos i t ion i ng Syste m
R A S Row Ad dress Stro be
R AT RAM Air Te m pera t u re is the te m pera t u re of the air
e n teri ng an air sc oop inle t . It is a factor in engi n e
perform a nce.
R / C R a te of Climb
R-C Res i stor- C a pac i tor networ k
R-C & W R ack Con n ectors and Wi ri ng
R C AG Re m o te Center Ai r / G ro und Sta t ion
P W M P ul se -Width Modula t ion
P W R Power
Q A R Q uick Access Rec ord er
Q C Q u a l i ty Con trol
Q E C Q u a dra n tral Error Corrector
Q F E A me th od of se t t i ng the altime ter to com pe n sa te for
ch a nges in ba rome tric press u re and runway eleva t ion .
P i lot rece ives inform a t ion from airfie ld and adjusts his
a l t i me ter acc ordi ng ly and it will read zero altitude at
to uch d own on the runway.
Q M Q u a l i ty Ma n age me n t
Q M P Q u a l i ty Ma n age ment Pla n
Q N E The me th od of se t t i ng the altime ter to the sta n d a rd
a tm os p h ere datum -29.92 inch es of mercu ry
( 1,013.25 m b ). This se t t i ng is used in the Un i ted Sta tes
a i r s pace by all airc raft above FL 180.
Q N H The more com m on me th od of se t t i ng the altime ter to
c om pe n sa te for ch a nges in ba rome tric press u re. P i lo t
rece ives inform a t ion from airfie ld, a d j usts his
a l t i me ter acc ordi ng ly and the altime ter will rea d
a i rfie ld eleva t ion at to uch d own .
Q O P Q u a l i ty Opera t i ng Procedu res
Q o S Q u a l i ty of Service
Q R H Q uick Refere nce Ha n dboo k
Q T Y Q u a n t i ty
Q UA D Q u a dra n t
Quadrantral E rror in the re la t ive bea ri ng caused by the di stort ion
E r r o r of the rece ived ra dio signal (RF fie lds) by th e
struct u re of the airc raft .
R ( 1 ) Rig h t
( 2 ) Ro u te Tun ed NAVAID
R A ( 1 ) Resol u t ion Advi sory (ge n era ted by TCA S )
( 2 ) R a dio A l t i me ter
( 3 ) Ro u t i ng Area
8 0
8 3
R E L Re la t ive
R E Q ( 1 ) Request
( 2 ) Requi red / Requi re me n t
R E R Res idual Error Rate
Resolution A di s play indic a t ion given to the pi lot rec om me n di ng
A d v i s o r y a maneuver to inc rea se vert ical se pa ra t ion re la t ive to
an intru di ng airc raft . A resol u t ion advi sory is also
c la ss i fied as correct ive or preve n t ive.
R E S T R Restrict ion
R E S Y N C I N G Resynch ron izi ng
R E T ( 1 ) R a pid Exit Ta xi way
( 2 ) Re l ia bi l i ty Eva l u a t ion Test
R E U Re m o te Electron ics Un i t
R F R a dio Freque nc y. A ge n eral term for the ra nge of
freque nc ies above 150 kHz, to the infra - red region
( 1012 Hz).
R F C Request for Com me n ts
R F I ( 1 ) R a dio Freque ncy In terfere nce
( 2 ) Request For Inform a t ion
R F P Request For Pro posa l
R F T P Request For Tech n ical Pro posa l
R F U R a dio Freque ncy Un i t
R G B Red / G ree n / Bl ue
R G C S P Review of the Ge n eral Concept of Se pa ra t ion Pa n e l
R H R a dio Ha n dler
R H O Res pon se on Ha n d off
R H S M Reduced Horizon tal Se pa ra t ion M i n i m a
R I B ( 1 ) Right Inboa rd
( 2 ) Ro u t i ng Inform a t ion Ba se
R I P Ro u t i ng Inform a t ion Pro toc ol
R I S C Reduced In struct ion Set Com p u ter
R I U R a dio In terface Un i t
R C C Re m o te Charge Converter
R C E R a dio Con trol Equi pme n t
R C L R a dio Com mun ic a t ions Link
R C O Re m o te Com mun ic a t ions Outle t
R C P ( 1 ) R a dio Con trol Pa n e l
( 2 ) Requi red Com mun ic a t ions Perform a nce
R C R Ro u t i ng and Circuit Restora l
R C V R Rece iver
R C U Re m o te Con trol Un i t
R & D Resea rch and Deve lo pme n t
R d R-Channel used for data
R DA R A Regional Domest ic Air Ro u te Area
R D C Ro u t i ng Domain Confed era t ion
R D F Ro u t i ng Domain Form a t
R D I Ro u t i ng Domain Id e n t i fier
R D M I R a dio Dista nce Magn e t ic In dic a tor
R D P Radar Da ta Process i ng (syste m )
R D R R a d a r
R D S S R a dio De term i n a t ion Sa te l l i te Service
R D U Rece iver / Dec od er Un i t
R DV Requi re me n ts Deve lo pment and Va l id a t ion
R DV S R a pid De ployment Voice Swi tch
R E C A P Re l ia bi l i ty Eva l u a t ion and Correct ive Act ion Progra m
R E F Refere nce
R E F L Reflect ion
Re f l e c t i v i t y This is a mea s u re ment of the abi l i ty of a ta rget to
Factor (Z) reflect the energy from a radar bea m .
Re l a t i v e The bea ri ng of a gro und sta t ion re la t ive to th e
B e a r i n g di rect ion the airc raft nose poi n ts, or the di rect ion of
an airc raft to or from an NDB.
8 2
8 5
RJ Regional Je t
R L E Res pon se on Link Esta bl i s hme n t
R L P Ri ng Laser Gyro
R L S ( 1 ) Re l ia ble Link So u rce
( 2 ) Re m o te Light Se n sor
R LY Re lay
R & M Re l ia bi l i ty and Ma i n ta i n a bi l i ty
R M & A Re l ia bi l i ty Ma i n ta i n a bi l i ty and Ava i la bi l i ty
R M I R a dio Magn e t ic In dic a tor
R M M S RM Ma n age ment Syste m
R M P ( 1 ) R a dio Ma n age ment Pa n e l
( 2 ) Re m o te Ma i n te n a nce Pa n e l
R- N AV Area Naviga t ion
R N G R a nge
R N G A R a nge Arc
R N P Requi red Naviga t ion Perform a nce
R N R Rece ive Not Rea dy
R N T P R a dio Nav Tun i ng Pa n e l
R O ( 1 ) R a dio O pera tor
( 2 ) Roll Out
R OA Rec ogn ized Opera t i ng Age nc y
R O B Right Outboa rd
R O C ( 1 ) R a te Of Climb
( 2 ) R a te of Opera t ional Capa bi l i ty
R O D R a te Of Desce n t
R O M ( 1 ) Read Only Me m ory
( 2 ) Ro ugh Ord er of Magn i t u d e
R O N Remain Over Nig h t
R OT H R Re loc a ta ble Over- T h e - Horizon Radar
R P Ro u t i ng Pro toc ol
8 4
R P I R a pid Process Im prove me n t
R P M Revol u t ions Per Minu te
R P OA Rec ogn ized Priva te Opera t ion Age ncy (CC ITT )
R R Rece iver Rea dy
R R I Ro u ter Refere nce Im ple me n ta t ion
R S D P Re l ia ble Seque nc i ng De l ivery Confi rm a t ion Pro toc ol
R S N Regional Subnetwor k
R S P ( 1 ) Requi red Surve i l la nce Perform a nce
( 2 ) Rever s ion Se lect Pa n e l
R S S I Rece ived Signal Stre ng th In dic a tor
R T ( 1 ) R a dio Te lec om mun ic a t ion
( 2 ) Rece iver- Tra n s m i t ter (R/T). A l so referred to as a
tra n sce iver. ( See T / R )
R TA ( 1 ) Rece iver- Tra n s m i t ter An te n n a
( 2 ) Requi red Ti me of Arriva l
R TC Rea l - Ti me Clock
R TC A R a dio Tech n ical Com m i ss ion for Aeron au t ic s
R TCA DO- 1 6 0 RTCA Document 160, Envi ronme n tal Con di t ions and
Test Procedu res for Ai r borne Equi pme n t , Iss ued
12 / 04 / 89
R TCA DO- 1 7 8 RTCA Document 178, Softwa re Con s id era t ions in
Ai r borne Systems and Equi pment Cert i fic a t ion ,
i ss ued 03 / 22 / 85
R T E Ro u te
R T F R a dio te le p h ony
R T I Rea l - Ti me In terroga te
R T M R a dio Tra n s m i ss ion Module
R T P Re l ia bi l i ty Test Pla n
R TO Re jected Takeoff
R TO S Rea l - Ti me Opera t i ng Syste m
R T P R a dio Tun i ng Pa n e l
8 7 8 6
R T R Re m o te Tra n s m i t ter Rece iver Site
R T S Request To Se n d
R T T I R un - Ti me Type Id e n t i fic a t ion
R T U R a dio Tun i ng Un i t
R U R ack Un i t
R u n w a y The act of inadverte n tly cross i ng the runway holdi ng
I n c u r s i o n point wi thout ATC clea ra nce.
R V D T Ro ta ry Vol tage Differe n t ial Tra n sducer
R V R R unway Visual Range
R V S M Reduced Vert ical Se pa ra t ion Minimum
R / W Rea d / Wri te
R W R unway
R W M Rea d -Wri te Me m ory. A me m ory in wh ich each cell is
se lected by applyi ng appro pria te electrical inp u t
s ign a l s, and the stored data may be eith er se n sed at
the appro pria te output terminal or ch a nges in
res pon se to oth er electrical input sign a l s.
R x Rece iver
R Z Re t u rn to Zero
S So u th
S 0 Segment O
S 1 Segment 1
S A ( 1 ) Se lect ive Ava i la bi l i ty
( 2 ) S i t u a t ion Awa re n ess
S A A Service Access Area
S A A R U Sec on d a ry Attitude Air Da ta Refere nce Un i t
S A E Soc ie ty of Au tom o t ive Engi n eer s
S A I System Arch i tect u re and In terface
S A M A Small Ai rc raft Ma nu fact u rers Assoc ia t ion
S A P Service Access Poi n ts
S A R Sea rch and Rescue
S A R P S S ta n d a rds And Rec om me n d ed Pract ices
S A S ( 1 ) S ta bi l i ty Augme n ta t ion Syste m
( 2 ) S ta t ion Ad dress Se t
S AT ( 1 ) S ta t ic Air Te m pera t u re is the to tal air te m pera t u re
c orrected for the Mach effect . Inc rea ses in
a i r s peed cause pro be te m pera t u re to ri se
prese n t i ng erron eo us inform a t ion . SAT is th e
o u ts ide air te m pera t u re if the airc raft could be
bro ught to a stop before mea s u ri ng te m pera t u res.
( 2 ) System Acce p ta nce Test
S ATC O M Sa te l l i te Com mun ic a t ion s
S AT N AV Sa te l l i te Naviga t ion
S B Service Bul le t i n
S B C S i ng le Boa rd Com p u ter
S B D Sch e m a t ic Block Diagra m
S B E S i ng le Bit Error
S / C S tep Climb
S C S pec ial Com m i t tee
SCAT S pec ial Category
S C D ( 1 ) S pec i fic a t ion Con trol Drawi ng
( 2 ) System Category Diagra m
S C D U Sa te l l i te Con trol Da ta Un i t
SCI D Softwa re Configu ra t ion In d ex Drawi ng
SCI U R a dio A l t i me ter In dic a tor
S C M Softwa re Configu ra t ion Ma n age ment
SCP C S i ng le Carrier Per Channel
SCS S i ng le Channel Simplex . A c om mun ic a t ion system th a t
uses simplex .
S C S I Small Com p u ter System In terface
S C U ( 1 ) S ignal Con di t ion i ng Un i t
( 2 ) S ignal Conver s ion Un i t
8 9
S E U ( 1 ) S i ng le Event Upse t
( 2 ) Seat Electron ics Un i t
S F D F S u bsystem Fault De tect ion Funct ion
S F E S u p pl ier Fu rn i s h ed Equi pme n t
S G S ignal Ge n era tor
S I ( 1 ) Se lect ive In terroga t ion
( 2 ) S ta n dby In strume n ts
( 3 ) S u p port i ng In terroga tor
S I C A S Sec on d a ry Surve i l la nce Radar Im prove me n ts and
C ol l i s ion Avoid a nce Syste m
S I C A S P Sec on d a ry Surve i l la nce Radar Im prove me n ts
And Col l i s ion Avoid a nce System Pa n e l
S I D S ta n d a rd In strument De pa rt u re
S i d e t o n e The re product ion of so un ds in a hea dset (or speaker )
from the tra n s m i t ter of the sa me com mun ic a t ion se t .
This allows a per son to hear his/her own voice wh e n
tra n s m i t t i ng.
S I F ( 1 ) S ta n d a rd In terch a nge Form a t
( 2 ) System In tegra t ion Fac i l i ty
S I G M E T S S ign i ficant Me teorological Observa t ion s
S I L ( 1 ) Systems In tegra t ion Lab
( 2 ) Service Inform a t ion Le t ter
S i m p l ex A c om mun ic a t ion opera t ion that uses only a sing le
channel for transmit and rece ive opera t ion s.
C om mun ic a t ions can take place in only one
di rect ion at a time.
S I P S i ng le In-line Pack age
S I TA Soc ie te In tern a t ion a le de Te lec om mun ic a t ion s
Aeron au t iques
S I T P / D System In tegra t ion Test Pla n / Desc ri p t ion
S I T System In tegra t ion and Test
S I T R System In tegra t ion Test Re port
S I U Sa te l l i te In terface Un i t
S D ( 1 ) S ide Display
( 2 ) S torm De tect ion . It is the des ign a t ion for th e
h o u rly tra n s m i t ted radar observa t ions from th e
N WS and A RTCC ra d a r s. In dividual SDs are
c om bi n ed and tra n s m i t ted once an hour as
c ol lect ives ( SDUs) over the avia t ion te le type
c i rcui ts.
S D D S ta n d a rd Disk Drive
S D I So u rce Dest i n a t ion Id e n t i fier
S D M S peaker Drive Module
S D P S u rve i l la nce Da ta Process i ng
S D R A M Synch ron o us Dyn a m ic Random Access Me m ory
S D R L S u p pl ier Da ta Requi re me n ts List
S D U ( 1 ) Sa te l l i te Da ta Un i t
( 2 ) Se n sor Display Un i t
( 3 ) Service Da ta Un i t
S e a r c h In this mod e, the DME scans from 0 mile to the outer
ra nge for a re ply pul se pair after tra n s m i t t i ng an
i n terroga t ion pul se pa i r.
S E C Sec on d a ry
S E D Sec on d a ry EICA SD i s play
SEI ( 1 ) Softwa re Engi n eeri ng In st i t u te
( 2 ) S ta n dby Engine In dic a tor
S E L ( 1 ) Se lect
( 2 ) Se lector Id e n t i fier
S E L C A L Se lect ive Calling Syste m . A system used in
c on j unct ion wi th HF and VHF com mun ic a t ion
systems that allows a gro un d - ba sed ra dio opera tor to
call a sing le airc raft or group of airc raft wi thout th e
a i rc raft per sonnel mon i tori ng the gro und sta t ion ra dio
freque nc y.
S e n s i t i v i t y An instruct ion given to the TCAS equi pment for
Level c on trol of its th reat vol ume.
C o m m a n d
S E P C Sec on d a ry Electrical Power Con tactor
S E P P S tress Eva l u a t ion Predict ion Progra m
S E R N O Serial Num ber
8 8
9 1
S M T ( 1 ) Ai leron / R u d d er Servo Mo un t
( 2 ) Eleva tor Servo Mo un t
( 3 ) Servo Mo un t
( 4 ) S ta bi l izer Trim Servo Mo un t
( 5 ) S ta n d a rd Message Text
( 6 ) S ta t ion Ma n age me n t
S N S u b n e twor k
S N A System Ne twork Arch i tect u re
S N AC S u b n e twork Access
S N A c P S u b n e twork Access Pro toc ol
S N C R S u b n e twork Con n ect ion Refere nce
S N D C F S u b n e twork De pendent Converge nce Funct ion
S N D C P S u b n e twork De pendent Converge nce Pro toc ol
S N I C F S u b n e twork In d e pendent Converge nce Funct ion
S N L E S u b n e twork Link Esta bl i s hme n t
S N M P S i m ple Ne twork Ma n age ment Pro toc ol
S N PA S u b n e twork Point of At tachme n t
S N P D U S u b n e twork Pro toc ol Da ta Un i t
S N R S ign a l - to - Noi se Ratio
S N S D U S u b n e twork Service Da ta Un i t
S O F Safe ty Of Fl ig h t
S O H S ta rt of Hea d er
S O I System Opera tor In struct ion s
S O I T Sa te l l i te Opera t ional Im ple me n ta t ion Tea m
S O M Softwa re Opera tor Ma nu a l
S O N S ta te ment of Opera t ional Need
S O P S ta n d a rd Opera t i ng Procedu re
S O PA S ta n d a rd Opera t i ng Procedu re Am pl i fied
S O S S i l ic on On Sa p p h i re
S P S pace
S k y w a v e A ra dio wave that is reflected by the ion os p h ere.
De pe n di ng upon the sta te of the ion os p h ere, th e
reflected ra dio wave may pro paga te along the layer
of the ion os p h ere or be reflected at some ang le. It
is also kn own as ion os p h eric or indi rect wave.
S L Se n s i t ivi ty Leve l
S / L S u b - Leve l
S L A Service Level Agree me n t
Slant Range The line-of - s ight di sta nce from the airc raft to a DME
gro und sta t ion .
S L C Synch ron o us Link Con trol
S L H System Level Hea l th
S L I System Level In terface
S L M S ta n d a rd Le ng th Message
S L o C So u rce Lines of Cod e
S L S S id e - Lo be Suppress ion . A system that preve n ts a
tra n s pon d er from re plyi ng to the sid e - lo be
i n terroga t ions of the SSR. Re plyi ng to sid e - lo be
i n terroga t ions wo uld supply fa l se re pl ies to the ATC
gro und sta t ion and obscu re the airc raft loc a t ion .
S L U C System Level Use Case
S LV ( 1 ) Service Level Veri fier
( 2 ) Sync Lock Va lve
S M A S u rface Move ment Advi sor
S M C System Ma n age ment and Com mun ic a t ion
S M D S u rface Mo unt Device
S M D S Swi tch ed Mul t i - mega bit Da ta Service
S M E System Ma n age ment En t i ty
S M G C S S u rface Move ment Guid a nce and Con trol Syste m s
S M I S ta n d a rd Message Id e n t i fier s
S M L S Sea m less Pipe and Tu be
S M S S pectrum Mon i tori ng Syste m
9 0
9 3
S q u i t t e r ( 1 ) The ra n d om pul se pairs ge n era ted by the gro un d
sta t ion as a fi l ler sign a l .
( 2 ) The tra n s m i ss ion of a spec i fied re ply format at a
m i n i mum ra te wi thout the need to be
i n terroga ted. ( Fi l ler pul ses tra n s m i t ted be twee n
i n terroga t ions) [XPD ] .
( 3 ) S pon ta n eo us Tra n s m i ss ion ge n era ted once per
sec ond by tra n s pon d er s.
S R Service Request
S R A D D Softwa re Requi re me n ts And Des ign Desc ri p t ion
S R A M S ta t ic Random Access Me m ory
S R D Systems Requi re me n ts Docume n t
S R E J Se lect ive Re ject
S R M Se lect ive Re ject Mod e
S R P Se lected Refere nce Poi n t
S R R Sa te l l i te Rec ogn i t ion Rece iver
S R T Sa te l l i te Rece iver Tra n s m i t ter
S R U Shop Re placea ble Un i t
S S B S i ng le Sid e ba n d. An AM signal that has a reduced
c a rrier, wi th the power appl ied to a sing le sid e ba n d.
S i nce the ba n dwidth of the inform a t ion - c a rryi ng
s ignal is reduced, a be t ter sign a l - to - n oi se ra t io is
o b ta i n ed at the rece iver.
S S C V / D R Sol id - S ta te Cock pit Voice / Da ta Rec ord er
S S C V R Sol id - S ta te Cock pit Voice Rec ord er
S S E C S ta t ic So u rce Error Correct ion
S S F D R Sol id - S ta te Fl ight Da ta Rec ord er
S S M S ign Sta t us Ma tri x
S S R Sec on d a ry Surve i l la nce Radar. A ra d a r- type
system that requi res a tra n s pon d er to transmit
a re ply sign a l .
S S S C S i ng le Sid e band Suppressed Carrier. A SSSC signal is
a band of au dio inte l l ige nce freque nc ies that have
been tra n s la ted to a band of ra dio freque nc ies wi th o u t
di stort ion of the inte l l ige nce sign a l .
S PAT E S pec ial Purpose Au tom a t ic Test Equi pme n t
S P C S ta t i st ical Process Con trol
S P D S peed
S P E Se l ler Purch a sed Equi pme n t
Speed of Re prese n ted by the sym bol c and has a va l ue of
L i g h t 2.9979250 x 108 me ter s / sec ond or
983,571,194 fee t / sec on d.
S P I S pec ial Pos i t ion Id e n t i fic a t ion
S P I P Des ign a t ion for a tra n s pon d er ident pul se.
S P K R S peaker
S P M ( 1 ) S ta bi l izer Pos i t ion Modules
( 2 ) S u rface Pos i t ion Mon i tor
S p o k i n g Refers to a di s play prese n ta t ion that ra dia tes outwa rd
from the di s play origin like the spo kes on a wagon
wh ee l .
S P R Sync Phase Rever sa l . ( Term is used in Mode S
tra n s pon d er s.)
S P S ( 1 ) Se n sor Process i ng Subsyste m
( 2 ) S ta n d a rd Pos i t ion i ng Service
SQ or Sql Sque lch
S Q Service Quality
S Q B Service Quality / Bi l l i ng Processor
S Q D Service Quality Da ta
S Q L S truct u red Query Langu age
S Q P S ignal Quality Pa ra me ter
Squall Line A squall line is a line of th un d er storms and
d eve lo pi ng th un d er storm s.
S q u a w k Re ply to interroga t ion signal (XPD ).
S q u e l c h A c on trol and/or circuit that reduces the gain in
res pon se of a rece iver. The sque lch is used to
e l i m i n a te the output noi se of the rece iver when a
s ignal is not be i ng rece ived.
9 2
9 5
S T D M A Synch ron ized Ti me Divi s ion Mul t i ple Access
S T E P C L B S tep Climb
S T I U Sa te l l i te Te lec om mun ic a t ions In termedia te Un i t
S T M Serial Tra n s i t ion Module
S TO L S h ort Takeoff and Landi ng
S T P S ta n d a rd Te m pera t u re and Press u re
S T S S ta ble Ti me Subfie ld
S T X S ta rt of Text
S U S ignal Un i t
S UA S pec ial Use Ai r s pace
S U L Yaw Da m per Act u a tor
S U O ( 1 ) Ai leron / Eleva tor / R u d d er Servo
( 2 ) Servo Act u a tor
S u p e r - A rece iver in wh ich the inc om i ng RF sign a l
h e t e r o d y n e is mixed to produce a lower intermedia te
Re c e i v e r freque nc y.
S u p p r e s s o r A p ul se used to di sa ble L-band avion ics du ri ng th e
P u l s e tra n s m i t t i ng period of anoth er piece of L-ba n d
a i r borne equi pme n t . It preve n ts the oth er avion ic s
a boa rd the airc raft from be i ng damaged or interfered
wi th by the tra n s m i ss ion and any noi se assoc ia ted
wi th that tra n s m i ss ion .
S U P P S Regional Supple me n ta ry Procedu res
S U T ( 1 ) Au to th ro t tle Servo
( 2 ) S ta bi l izer Trim Servo
( 3 ) System Un d er Test
S V S pace Ve h ic le
S V C ( 1 ) Service
( 2 ) Swi tch ed Vi rtual Circui t
S VO Servo
S V R R Service Rea di n ess Review
S V T Servo T h ro t tle
S S U S u bsequent Signal Un i t
S T S ta t i st ic s
s t a S ta t ion
S TA B S ta bi l izer
S t a n d a r d Re prese n ts the mean or average pro pert ies of th e
A t m o s p h e r e a tm os p h ere. At sea level sta t ic press u re is 29.92 In H g
and te m pera t u re is +15 ° C.
S t a n d b y A DME mode that appl ies power to the DME RT b u t
M o d e the unit does not tra n s m i t .
S TA R S ta n d a rd Terminal Arrival Ro u tes
S TA R S S ta n d a rd Terminal Au tom a t ion Re place ment Syste m
Static Po r t s Fl us h - m o un ted ope n i ngs in the skin of the airc raft
fuse lage used to se n se sta t ic press u re.
S t a t i c Am bient atm os p h eric press u re or sta t ic press u re is
P r e s s u r e the force per unit area exerted by the air on th e
s u rface of a body at rest re la t ive to the air.
Static RAM RAM con structed of bi sta ble tra n s i stor ele me n ts.
Me m ory cells do not requi re refres h i ng.
( See Dyn a m ic RA M.)
Static Source A c orrect ion appl ied to sta t ic so u rce press u re
Error (SSEC) mea s u re me n ts to pa rtly or com ple te ly correct for
press u re errors that are caused by airflow ch a nges. It is
c om p u ted as a funct ion of Mach and altitude ba sed on
mea s u red errors for a pa rt icular sta t ic syste m .
S T B Systems Test bed
S T B Y S ta n dby In strume n ts
S TC ( 1 ) Se n s i t ivi ty Ti me Con trol . A c on trol circuit used
in radar appl ic a t ions to con trol rece iver gain wi th
res pect to time.
( 2 ) S u p ple me n tal Type Cert i fic a te
S TC M S ta bi l izer Trim Con trol Module
S T D ( 1 ) S ta n d a rd
( 2 ) System Tech n ical Desc ri p t ion
S T D B Y S ta n dby In strume n ts
9 4
9 7
TAU TAU is the minimum time a fl ight crew needs to
di scern a col l i s ion th reat and take eva s ive act ion . It
re prese n ts the perform a nce enve lo pe (speed and pa th
of airc raft) divid ed by the clos u re ra te of any intru d er
a i rc raft (TCA S ).
TAW S Terrain Awa re n ess Wa rn i ng Syste m
T B B Tra n sfer Bus Breaker
T B D To Be De term i n ed
T B O Ti me Be tween Overh aul s
T B S ( 1 ) To Be Spec i fied
( 2 ) To Be Suppl ied
TC ( 1 ) Tra n s port Con n ect ion
( 2 ) Type Cert i fic a te
T / C To p - of - C l i m b
TCA ( 1 ) Terminal Con trol Area
( 2 ) T h ro t tle Con trol Asse m bly
TCA S Traffic A lert Col l i s ion Avoid a nce Syste m
TCAS I A ba seline system that provid es a wa rn i ng (TA) to th e
fl ight crew of the prese nce of anoth er airc raft
( po te n t ial col l i s ion th reat) wi thin the surve i l la nce
a rea . No avoid a nce maneuver is sug gested.
TCAS II A c ol l i s ion avoid a nce system providi ng traffic
i nform a t ion (wi thin approxi m a te ly 30 nmi of th e
a i rc raft) to the fl ight crew, in addi t ion to the resol u t ion
a dvi sories (RA) (for vert ical maneuvers only ). A
TCA S I I - equi p ped airc raft will coordi n a te wi th
TCA S I I - equi p ped intru d er airc raft to provid e
c om ple me n ta ry maneuver s.
TC C Tu r bine Case Cool i ng
TC F Terrain Clea ra nce Floor
TC M Tech n ical Coordi n a t ion Mee t i ng
TC M S Test Con tent Ma n age ment Syste m
TC N TACA N
TC P Tra n s m i ss ion Con trol Pro toc ol
S V U Sa te l l i te Voice Un i t
S / W Softwa re
S WA P Severe Wea th er Avoid a nce Progra m
S W I T Softwa re In tegra t ion and Test
S W T R R Softwa re Test Rea di n ess Review
s y s Syste m
S Y S System Id e n t i fier
S Y S C AT- B System Category B (FA A Message Form a t )
S Y S C I System Configu ra t ion Ite m
TA Traffic Advi sory (TCA S )
TA D Terrain Awa re n ess Display
TAC ( 1 ) Test Access Con trol
( 2 ) T h rust Asym me try Com pe n sa t ion
TAC A N The Tact ical Air Naviga t ion System that provid es
azi mu th and di sta nce inform a t ion to an airc raft from
a fi xed gro und sta t ion (as opposed to DME providi ng
only di sta nce inform a t ion ).
Ta c h Tach ome ter
TACI U Test Access Con trol In terface Un i t
TA F Terminal Area Forec a st (ICAO )
TA I T h ermal An t i - Ic i ng
TA P Terminal Area Product ivi ty
TA R Trials ATN Ro u ter
Ta r g e t An airc raft wi thin the surve i l la nce ra nge of TCA S.
TA S True Ai r s peed
TAT ( 1 ) To tal Air Te m pera t u re. The air te m pera t u re
i nc l u di ng heat ri se due to com press i bi l i ty.
( 2 ) True Air Te m pera t u re
TATC A Terminal Air Traffic Con trol Au tom a t ion
9 6
9 9
T F T Thin Film Tra n s i stor
T F T P Trivial Fi le Tra n sfer Pro toc ol
T F T S Terrestrial Fl ight Te le p h one Syste m
T G ( 1 ) Ti mer - V DL Ma n age ment En t i ty
( 2 ) Tra n s m i ss ion Ga te
T G 3 GS’s Ma xi mum Ti me Be tween Tra n s m i ss ion s
T G 4 Ma xi mum Ti me Be tween GSIF’s Ti mer
T G C Tu r b ule nce Gain Con trol
T G S Ma xi mum Link Overlap Ti mer
T GT Ta rge t
T H D G True Hea di ng
T H R T h rust
THR HOLD T h ro t tle Hold
T h r e a t A ta rget that has sa t i sfied the th reat detect ion logic
and th us requi res a traffic or resol u t ion advi sory
( TCA S ).
T H S A Tri m m a ble Horizon tal Sta bi l izer Act u a tor
T I A Te lec om mun ic a t ions In dustry Assoc ia t ion
T I A S True In dic a ted Ai r s peed
T I S Traffic Inform a t ion Service
T K Track Ang le
T K E Track Ang le Error
T / L To p - Leve l
T L Terminal Loc a t ion (ACA RS / AFE PS )
T L A T h rust Lever Ang le
T L M Te le me try Word
T L S Ta rget Level of Safe ty
T M Ti mer - Media Access Con trol
T M A Terminal Con trol Area
TC P I P Tra n s port Con trol Pro toc ol / In ternet Pro toc ol
TC Q T h ro t tle Con trol Quadra n t
TC S To uch Con trol Steeri ng
TC U ( 1 ) TACAN Con trol Un i t
( 2 ) Te le p h one Conver s ion Un i t
TCXO Te m pera t u re Con trol led Crystal Osc i l la tor
T / D To p - of - Desce n t
T D L S Tower Da ta Link Syste m
T D M In the Ti me Divi s ion Mul t i plex Systems a com m on
c a rrier is shared to transmit mul t i ple messages (to
mul t i ple rece ivers) by time shari ng the carrier
be tween the message so u rces.
T D M A Ti me Divi s ion Mul t i plex Access. When mul t i ple
tra n s m i t ters are us i ng a sing le carrier to transmit to a
s i ng le rece iver, the carrier is time shared be twee n
each of the tra n s m i t ter s, so the mul t i ple messages are
not ga r bled at the rece iver.
T D O P Ti me Dilution Of Prec i s ion . A term used to desc ri be
the error introduced by va ria nces in the calcula ted
t i me.
T D R Tra n s pon d er
T D S Terminal Display Syste m
T D S T Tower Da ta Services Term i n a l
T DW R Terminal Do p pler Wea th er Radar
T E C T h erm o - Electric Cooler
T E I Text Ele ment Id e n t i fier s
T E M P Te m pera t u re
Temperature A se n sor pro tru di ng into the airstream to se n se air
P r o b e te m pera t u re. Requi res correct ion to get sta t ic air
te m pera t u re.
T E R P S ( 1 ) Terminal En Ro u te Procedu res
( 2 ) Terminal In strument Procedu res
T E S Trials End System (for AT N )
T F M Traffic Flow Ma n age me n t
9 8
1 0 1
T R Te m pora ry Revi s ion . A d ocume n t , pri n ted on ye l low
pa per that te m pora ri ly ame n ds a page or pages of a
c om ponent mainte n a nce manu a l .
T / R ( 1 ) T h rust Rever ser
( 2 ) Tra n sce iver (see RT )
( 3 ) Tra n s m i t ter- Rece iver
T R A ( 1 ) Te m pora ry Reserved Ai r s pace
( 2 ) T h rust Reduct ion A l t i t u d e
T R AC Terminal Radar A p proach Con trol
Tr a c k ( 1 ) The actual pa th , over the gro un d, trave led by an
a i rc raft (naviga t ion ).
( 2 ) In this mode the DME tra n s m i ts a reduced pul se
pair ra te after acqui ri ng lock - on (DME ).
( 3 ) E st i m a ted pos i t ion and ve loc i ty of a sing le
a i rc raft ba sed on corre la ted surve i l la nce data
re ports (TCA S ).
T R AC O N Terminal Radar A p proach Con trol
T R AC S Test and Re pair Con trol Syste m . An au tom a ted data
re trieval syste m .T RACS funct ions include: 1) provid e
the loc a t ion of any given unit at any time; 2) provid e
an effic ient flow of work to and from test sta t ion s ;
3 ) provide quick access to qu a l i ty inform a t ion
ge n era ted by the actual test i ng process (performed by
the tech n ic ian); 4) provide sta t i st ical and historic a l
d a ta rega rdi ng th ro ughput time for products, fa i l u re,
yie ld ra tes, WIP, e tc.
Tr a f f i c Inform a t ion given to the pi lot perta i n i ng to th e
A d v i s o r y pos i t ion of anoth er airc raft in the immedia te vic i n i ty.
The inform a t ion con tains no sug gested maneuver s.
( Traffic advi sory airspace is 1200 feet above and be low
the airc raft and approxi m a te ly 45 sec on ds di sta n t
wi th res pect to clos u re speed of the airc raft .) [TCA S ]
Tr a f f i c The num ber of tra n s pon d er- equi p ped airc raft wi th i n
D e n s i t y R nau t ical miles (nmi) of own airc raft , divid ed by p x
(R nm i )
2
. Tra n s pon d er- equi p ped airc raft inc l u d e
Mode S and ATC RBS Mode A and Mode C, a n d
exc l u d es own airc raft . ( TCA S )
T R A N S Tra n s i t ion
Tr a n s c e i v e r A rece iver and tra n s m i t ter com bi n ed in a sing le un i t .
Sa me as RT.
T M C T h rust Ma n age ment Com p u ter
T M C F T h rust Ma n age ment Com p u ter Funct ion
T M C S T h rust Ma n age ment Com p u ter Syste m
T M F T h rust Ma n age ment Funct ion
T M S ( 1 ) T h rust Ma n age ment Syste m
( 2 ) Traffic Ma n age ment Syste m
T M U Traffic Ma n age ment Un i t
T N True North
TO Take Off
TO C ( 1 ) Top of Climb
( 2 ) Tra n sfer of Com mun ic a t ion s
TO D Top of Desce n t
TO EPR Takeoff Engine Press u re Ratio
TO / F R O M In dic a tes wh e th er the om n i bea ri ng se lected is th e
I n d i c a t o r c o u r se to or from the VOR gro und sta t ion .
TO G A Take Off, Go - Aro un d. A l so seen as TO / GA .
TO N1 Take Off Engine Fan Speed
TO R Terms of Refere nce
TOT To ta l
Touchdown The point at wh ich the pred e term i n ed glid e pa th
i n terce p ts the runway.
TO W Ti me Of Wee k
T P M U Ti re Press u re Mon i tor Un i t
T P Test Poi n t
T P 4 Tra n s port Pro toc ol Cla ss 4
T P D U Tra n s port Pro toc ol Da ta Un i t
T P L Terminal Perm i ss ion List (ACA RS / AFE PS )
T P M Tech n ical Perform a nce Ma n age me n t
T P R Tra n s pon d er
T Q A T h ro t tle Quadrant Asse m bly
1 0 0
1 0 3
T S O Tech n ical Sta n d a rd Ord er. Every unit built wi th a TSO
n a me pla te must meet TSO requi re me n ts. TSO
o pera t i ng te m pera t u re extre mes are not the sa me as
the manu fact u ri ng burn-in limits.
T S S Tech n ology Support and Services
T S T M Ti me So u rce Tra n s i t ion Module
T T ( 1 ) Test Tool s
( 2 ) To tal Te m pera t u re
TT F F Ti me To Fi r st Fi x
T T L Tra n s i stor - Tra n s i stor Logic
T T R TCAS II Rece iver / Tra n s m i t ter
T T S Ti me To Sta t ion , an indic a t ion that di s plays th e
a m o unt of time for an airc raft to reach a se lected
DME gro und sta t ion wh i le trave l i ng at a con sta n t
s peed.
T T Y Te le typewri ter
T U R B Tu r b ule nce
Tu r b u l e n c e The U. S. Na t ional Wea th er Service defi n es lig h t
t u r b ule nce as areas wh ere wind ve loc i ty shifts are 0
to 19 feet per sec ond (0 to 5.79 me ters per sec ond) and
m od era te turbule nce as wind ve loc i ty shifts of 19 to 35
feet per sec ond (5.79 to 10.67 me ters per sec on d ).
T V B C Tu r bine Vane and Blade Cool i ng
T V C Tu r bine Vane Cool i ng
T V E To tal Vert ical Error
T W D L ( 1 ) Terminal Wea th er Da ta Link
( 2 ) Two Way Da ta Link
T W D R Terminal Do p pler Wea th er Radar
T W I P Terminal Wea th er Inform a t ion for Pilo ts
T W P Tech n ical Work Progra m
T W R Tu r b ule nce Wea th er Radar
T W T Trave l i ng Wave Tu be
Tr a n s p o n d e r Avion ics equi pment that re t u rns an id e n t i fyi ng cod ed
s ign a l .
T R D Transit Ro u t i ng Dom a i n
T R K Track
T R P Mode S Tra n s pon d er
T R R ( 1 ) Test Rea di n ess Review
( 2 ) Test Re ject ion and Re pa i r
T R S B Ti me Refere nce Sc a n n i ng Bea m . The intern a t ion a l
sta n d a rd for MLS insta l la t ion s.
T R U ( 1 ) Tra n sformer Rect i fier Un i t
( 2 ) True
True Airspeed The true ve loc i ty of the airc raft th ro ugh th e
s u rro un di ng air mass.
True Altitude The exact di sta nce above mean sea level (corrected
for te m pera t u re ).
True Bearing The bea ri ng of a gro und sta t ion wi th res pect to
true north .
True North The di rect ion of the north pole from the observer.
T S ( 1 ) Ti me So u rce
( 2 ) Tra n s port Service
T S A ( 1 ) Tail Stri ke Asse m bly
( 2 ) Tech n ical Service Agree me n t
T S A P Tra n s port Service Access Poi n t
T S C Term Service Com m i tme n t
T S D I U Tra n s port Service Da ta Un i t
T S E To tal System Error
T S I P Tri m ble Sta n d a rd In terface Pro toc ol
T S M Au to th ro t tle Servo Mo unt (wi thout Clutch )
T S P ( 1 ) Tra n s m i t ted Signal Power
( 2 ) Twi sted Shie ld ed Pa i r
1 0 2
1 0 5
U S A F Un i ted Sta tes Air Force
U S B U p per Sid e band is the inform a t ion - c a rryi ng band and
is the freque ncy produced by addi ng the carrier
freque ncy and the modula t i ng freque nc y.
U S T B Un sta bi l ized
U TC Un iver sal Coordi n a ted Ti me
U T P Un s h ie ld ed Twi sted Pa i r
U U T Unit Un d er Test
U V U p per Sid e band Voice
U W Un ique Word
V ( 1 ) Ve loc i ty
( 2 ) Vol t
V 1 C ri t ical engine fa i l u re ve loc i ty
V 2 Takeoff climb ve loc i ty
VA Vol t - Am peres
VAC Vol ts A l tern a t i ng Curre n t
VA P ( 1 ) Va l ue Ad d ed Processor
( 2 ) Visual Aids Pa n e l
VA P S ( 1 ) Vi rtual A p pl ic a t ions Pro to typi ng Syste m
( 2 ) Vi rtual Avion ics Pro to typi ng Syste m
VA R ( 1 ) Va ria t ion
( 2 ) Vi s u a l - Au ral Radio Range
( 3 ) Vol t - Am ps React ive
VA S I Visual A p proach Slo pe In dic a tor
VAU Vol tage Averagi ng Un i t
V B V Va ria ble Bypa ss Va lve
V C ( 1 ) Des ign Crui s i ng Speed
( 2 ) Vi rtual Circui t
V C B Vi rtual Circuit Bridge
V C D ( 1 ) Va ria ble Capac i ta nce Diod e
( 2 ) Vol tage Con trol led Device
T X Transmit (see XMIT )
UA Un num bered Ackn owledgme n t
UA R T Un iver sal Asynch ron o us Rece iver / Tra n s m i t ter
UAT Un iver sal Access Tra n sce iver
U B U t i l i ty Bus
U B I U pl i nk Block Id e n t i fier
U C I User Com p u ter In terface
U C S Un i form Chrom a t ic i ty Sc a le
U D User Da ta . The N-User data may also be tra n sferred
be tween peer network me m bers (OSI Model) as
requi red.
U D P User Da tagram Pro toc ol
U F D R Un iver sal Fl ight Da ta Rec ord er
U H F U l tra - H igh Freque nc y. The port ion of the ra dio
s pectrum from 300 MHz to 3 GH z .
U I Un num bered Inform a t ion
U I R U p per Inform a t ion Region
U L U pl i nk
U L B Un d erwa ter Loc a tor Beac on
U L D Unit Load Device
U M L Un i fied Mod e l i ng Langu age
U M T Un iver sal Mo un t
U n p a i r e d A DME channel wi thout a corres pon di ng VOR or
C h a n n e l ILS freque nc y.
U p l i n k The ra dio tra n s m i ss ion pa th upwa rd from the ea rth
to the airc raft .
U P Un iver sal Pla t form
U P R M Un iver sal Pla t form Reso u rce Ma n age me n t
U P S M S U PS Ma n age ment Syste m
U P S Un i n terru p t i ble Power Supply
1 0 4
1 0 7
V I G V Va ria ble In tegral Guide Va n e
V I S TA Vi rtual In tegra ted Softwa re Test bed for Avion ic s
V I U Vid eo In terface Un i t
V / L VOR / Loc a l izer
V L E L a n di ng Gear Exte n d ed Plac a rd Ai r s peed
V L F Very Low Freque nc y
V LO Ma xi mum Landi ng Gear of Opera t i ng Speed
V LO F L i ft - off Speed
V L S I Very Large Sc a le In tegra t ion
V LV Va lve
V M Hea di ng to a manual term i n a t ion
V / M Vol tme ter
V M A X Ba s ic Clean Ai rc raft Ma xi mum CA S
VMC ( 1 ) Visual Me teorological Con di t ion s
( 2 ) M i n i mum Con trol Speed wi th Cri t ical Engi n e
O u t
V M E ( 2 ) Ver sa Module Euroc a rd Bus
( 1 ) VHF Ma n age ment En t i ty, V ME bus
V M E C C Ver sa Module Euroc a rd Card Cage
V M I N Ba s ic Clean Ai rc raft Minimum CA S
V M ( LO ) M i n i mum Ma n e uver Speed
V m o The maxi mum airspeed at wh ich an airc raft is
cert i fied to opera te. This can be a fi xed num ber or a
funct ion of configu ra t ion (gea r, fla ps, e tc.), or altitude,
or bo th .
V M O N V N MS Hea l th Mon i tori ng
V / N AV Vert ical Naviga t ion
V N E Never- E xceed Speed
V N O Ma xi mum Struct u ral Crui s i ng Speed
V N R V H F Naviga t ion Rece iver
V C M A X Act ive Ma xi mum Con trol Speed
V C M I N Act ive Minimum Con trol Speed
V C O Va ria ble Con trol led Osc i l la tor
V C U V DL C on trol Un i t
V D ( 1 ) Des ign Divi ng Speed
( 2 ) Hea di ng to a DME Dista nce
V D C Vol ts Direct Curre n t
V D L VHF Da ta Link
V D R VHF Digi tal Radio
V E R Ver s ion
Ve r t i c a l The ra te of ch a nge of press u re altitude, us u a l ly
S p e e d c a l i bra ted in hun dreds of feet per minu te.
V F Des ign Flap Speed
V F E Fla ps Exte n d ed Plac a rd Speed
V F O Va ria ble Freque ncy Osc i l la tor
V F O P Visual Fl ight Rules Opera t ions Pa n e l
V F R Visual Fl ight Rules
V F X R ( R ) Flap Re tract ion Speed
V F X R ( X ) Flap Exte n s ion Speed
V G / D G Vert ical Gyro / D i rect ional Gyro
VG or VGND G ro und Ve loc i ty
V G A Vid eo Gra p h ics Ad a p ter
V H Ma xi mum Leve l - fl ight Speed wi th Con t i nu o us Power
V H F Very High Freque nc y. The port ion of the ra dio
s pectrum from 30 to 300 MHz.
V H S Very High Speed
V H S I C- 2 Very High Speed In tegra ted Circui ts - Phase 2
V I Hea di ng to a course interce p t
V I s Lowest Se lecta ble Ai r s peed
1 0 6
1 0 9
VSL Advisory Vert ical Speed Limit Advi sory may be preve n t ive or
c orrect ive (TCA S )
V S M Vert ical Se pa ra t ion Minimum
V S O S ta l l i ng Speed in the Landi ng Configu ra t ion
V S TO L Vert ical or Short Takeoff and Landi ng
V S V Va ria ble Sta t ion Va n e
V S W R Vol tage - S ta n di ng Wave Ratio. The ra t io of th e
a m plitude of the vol tage (or electric fie ld) at a vol tage
m a xi mum to that of an adjacent vol tage minimum .
VSWR is a mea s u re ment of the mismatch be twee n
the load and the tra n s m i ss ion line.
V T K Vert ical Track Dista nce
V TO Vol ume tric To p - Off
V TO L Vert ical Takeoff and Landi ng
V T R Va ria ble Takeoff Rating
V / T R K Vert ical Track
V U U t i l i ty Speed
V X S peed for Best Ang le of Climb
V Y S peed for Best Rate of Climb
W ( 1 ) Wa t t
( 2 ) West
WA A S Wide Area Augme n ta t ion System (Me th od of
D i ffere n t ial GPS )
WA D G N S S Wide Area Differe n t ial Glo bal Naviga t ion
Sa te l l i te Syste m
WA F S World Area Forec a st Syste m
WA I Wi ng An t i - Ice
WA N Wide Area Ne twor k
WA R C- 9 2 World Adm i n i stra t ive Radio Confere nce (1992 )
WA R C- M O B World Adm i n i stra t ive Radio Confere nce for the
Mo bi le Service
VO C R A D Voice Radio
VO D Vid eo On De m a n d
Vo i s p o n d A CA LSE L funct ion that wo uld au tom a t ic a l ly id e n t i fy
an airc raft by a voice rec ordi ng. Voi s pond is not
yet imple me n ted.
VO M Vol t - Ohm - M i l l ia m me ter
VO R VHF Omnidi rect ional Radio Range. A system th a t
provid es bea ri ng inform a t ion to an airc raft .
VO R / D M E A system in wh ich a VOR and DME sta t ion are
c o - loc a ted.
VO R / M B VOR / Ma r ker Beac on
VO R TAC A system in wh ich a VOR and a TACAN sta t ion
a re co-loc a ted.
VO S Ve loc i ty Of So un d
VOX Voice Tra n s m i ss ion
V PAT H Vert ical Pa th
V P N Ve n d or Pa rt Num ber
V R ( 1 ) Takeoff Ro ta t ion Ve loc i ty
( 2 ) Hea di ng to a ra dia l
V R A M Vid eo Random Access Me m ory
V R E F Refere nce Ve loc i ty
V R G V DL Refere nce Guid e
V / S Vert ical Speed
V S AT Very Small A pert u re Term i n a l
V S C F Va ria ble Speed Con stant Freque nc y
VSCS ( 1 ) Vert ical Sta bi l izer Con trol System used on
NOTAR helic o p ter
( 2 ) Voice Swi tch i ng and Con trol Syste m
V S D V DL S pec i fic DTE Ad dress
V S I ( 1 ) Vert ical Speed In dic a tor
( 2 ) S ta l l i ng Speed in a Spec i fied Fl ight Configu ra t ion
1 0 8
1 1 1
W O W We ight On W h ee l s
W P Wor ki ng Pa per
W P T Waypoi n t
W P R Waypoint Pos i t ion Re port
W R S Wide- a rea Refere nce Sta t ion
W R T W X R Rece iver / Tra n s m i t ter
W S D D M Wea th er Support for De ic i ng Dec i s ion Maki ng
W / S T E P Wi th Step Change in A l t i t u d e
W T We ig h t
W X Wea th er
W X I W X R In dic a tor
W X P Wea th er Radar Pa n e l
W X R Wea th er Radar Syste m
W W W World Wide We b
W Y P T Waypoint A l t i t u d e
X A A R INC
X- B A N D The freque ncy ra nge be tween 8000 and 12500 MHz
X B In tern a t ional Air Tra n s port Assoc ia t ion (IATA )
X-C h a n n e l A DME ch a n n e l .T h ere are 126 X-Channels for DME
o pera t ion . For the fi r st 63 ch a n n e l s, the gro un d - to - a i r
freque ncy is 63 MHz be low the air- to - gro un d
freque nc y. For the sec ond 63-X Channels the
gro un d - to-air freque ncy is 63 MHz above the
a i r- to - gro und freque nc y.
XC V R Tra n sce iver
X F R Tra n sfer
X I D E xch a nge Id e n t i fic a t ion
X LT R Tra n s la tor
X M E xternal Ma ster
X M I T Tra n s m i t
X M T R Tra n s m i t ter
WAT R S West Atla n t ic Ro u te Struct u re
Wa y p o i n t A pos i t ion along a ro u te of fl ig h t .
W B C We ight and Ba la nce Com p u ter
W C P W X RC on trol Pa n e l s
W D Wind Direct ion
W E S Wa rn i ng Electron ic Syste m
W E U Wa rn i ng Electron ic Un i t
W FA W X R Flat Pla te An te n n a
W G S World Geod e t ic Syste m
W G S- 7 2 World Geod e t ic Survey of 1972
W G S- 8 4 World Geod e t ic System 1984
W h i s p e r - A seque nce of ATC RBS interroga t ions and
S h o u t s u p press ions of va ryi ng power levels tra n s m i t ted by
TCAS equi pment to reduce severi ty of synch ron o us
i n terfere nce and mul t i pa th pro ble m s.
W I N D M G Wind Magn i t u d e
W I N D R Wind Direct ion
WI P Work In Progress
W L D We ld ed Pipe and Tu be
W M A WXR An tenna Ped estal and WXR Waveguid e
Ad a p ter
W M I WXR In dic a tor Mo un t
W M O World Me teorological Orga n iz a t ion
W / M O D Wi th Modi fic a t ion of Vert ical Profi le
W M S Wide- a rea Ma ster Sta t ion
W M S C Wea th er Message Swi tch i ng Center
W M S C R Wea th er Message Swi tch i ng Center Re place me n t
W M T W X R Mo un t
W N Week Num ber
W O R D G ro u pi ng of bi ts. S ize of group va ries from
m ic ro processor to mic ro processor.
1 1 0
X P D ATC Tra n s pon d er (also XPDR, X PN DR, T PR )
X P D R Tra n s pon d er
X S SITA
X T I X / O pen Tra n s port In terface
X T K C rosstrack (crosstrack error )
X T P E xpress Tra n sfer Pro toc ol
Yagi Antenna An antenna wi th its maxi mum ra dia t ion pa ra l lel to
the long axis of its array, c on s i st i ng of a driven di pole,
a pa ra s i t ic di pole reflector, and one pa ra s i t ic di pole
di rector or more.
Y S A S Yaw Sta bi l i ty Augme n ta t ion Syste m
Y D Yaw Da m per
Z ( 1 ) Refer to reflect ivi ty factor
( 2 ) Z ulu (GM Ti me )
Z F W Zero Fuel We ig h t
Z- M a r ke r A m a r ker beac on , some t i mes referred to as a sta t ion
loc a tor, that provid es pos i t ive id e n t i fic a t ion to the
pi lot when the airc raft is pa ss i ng di rectly over a
low-freque ncy naviga t ion aid.
1 1 2

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