Introducing ACARS
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ACARS FREQUENCIES
MHz 131.55 131.550 0 130. 130.02 025 5 129. 129.12 125 5
Function Primar Primary y USA/ USA/Can Canada ada Seco Second ndar ary y USA Tert Tertia iary ry USA USA
131. 131.72 725 5 Prima Primary ry Europ Europe e 131. 131.45 450 0 Prima Primary ry Japa Japan n 131. 131.47 475 5 Priv Privat ate e Air Canada s
Aeronautical Radio, Inc. (commonly known as: "ARINC") maintains a huge VHF and HF voice network throughout the United States and overseas to provide operational radio communications for the aircraft aircraft industry. In the early eighties they developed an addressable, digital data link for commercial and business jets and their respective companies known as ACARS. ACARS stands for Aircraft Communications Addressing and Reporting System . System . It was produced to reduce the flight crew's work-load by using modern computer technology to exchange many routine reports reports and messages. This improves the safety safety and efficiency of modern air travel. ACARS uses the AM mode because the same airborne VHF radio is often also used for voice communications. Burst transmissions are used with a limit of 220 characters per message. Transmissions often last less than one second! Therefore when monitoring ACARS it is important to leave your receiver's squelch off. To monitor ACARS transmissions you will need a VHF scanner or receiver capable of tuning the VHF (AM) aircraft band 118 to 136 MHz. ACARS messages are very structured. Each position in the message has a specific function. The very common Q0 Link Test is shown as an example below.
Address Field
Message Label
Downlink Block Identifier
ACARS DECODERS
Q01 5400UA1750
.N9009U
Message Sequence Number
Universal ACT-1 Interface This compact PC interface simply plugs into the serial port of your PC. The supplied user-friendly software includes mouse support. You can view, filter, print and save the data. You can also view, search and print previously logged data. Includes a free copy of the book Understanding ACARS . Under $100. AOR ARD-2 Here is a "go anywhere" decoder for ACARS and NAVTEX. It provides portable operation from 4 internal AA cells (not supplied) or external 12 VDC, and a computer is notrequired. ACARS is the VHF teletype mode audible on most scanners. NAVTEX stands for Navigational Telex, sent predominantly on the longwave frequencies of 518 and 424 kHz, audible on most shortwave communications receivers. Incoming text is displayed on the 16 character by 2 line LCD display. A built-in speaker with volume control allows you to monitor activity. A 9600 baud DB9 serial port is provided for optional use with a personal computer. Under $400. Introducing ACARS
Carrier & Flight Number
There are nearly one hundred "standard" ACARS message formats plus a virtually unlimited number of airline specific company formatted message types. The following two examples are typical of standard ACARS message formats.
The QG OUT/RETURN IN REPORT, like many other ACARS downlinks, is transmitted automatically. Many ACARS downlinks are sent automatically as a result of on-board sensor activation, especially during takeoff and landings. This report is transmitted by an aircraft that leaves the gate, but for some reason must return back to the gate. x
QG - OUT/RETURN IN REPORT Tail Number N330AA Message Type QG
.N330AA
QG
3115 AA001SFO05070516
Return Back To Gate 0516 Out From Gate 0507 Origin San Francisco Flight Number American #1 Message Sequence 3115 in min. and sec. past the hour. Page 1
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Tail Number N370 US Air Message Type Q1 Out 0731 Off 0743 Fuel 0300 Destination Pittsburgh Free Talk Captain First Officer Flight Attendant
Q1 - DEPARTURE/ARRIVAL RPT.
This report is sent from the aircraft informing the ground station the time it left the gate, the wheels-up time, the destination, fuel and other data.
N370AU N370AU
Q1
4243 AL0604 SFO07310743 30588/A3 34613 7
0300PIT/FP
431/DC 0730/CO 29849/FO 37531/A1 30152/A
Origin San Francisco Flight Message Sequence 4243 in min. and sec. past the hour. s
MESSAGE TYPES
Label _j _ DELô
SMI
00 2S 2U 4M 51 52 54 57 5D 5P 5R 5U 5Y 5Z 7A 7B 80-9 A1 A2 A4 A5 A6 A7 A8 A9 A0 B1 B2 B3 B4 B5 B6 B7 B8 B9 C0 C1 C2 C3 CA
HJK
ò
AGM ô ò ò ò ò ò ò ò ò ò ò ñ ñ ñ ñ ñ ñ ñ ñ ñ ò ò ò ò ò ò ò ò ò ñ ñ ñ ñ
AEP TIS AEP WXR ETA AGM ENG ABM CLX CLD RCA RPR RAR FTU DDS DAI AFN RCL CLA RCD PPR PAR FTD RDS RAI
Message Title No info to transmit. Polled mode ¹ General response, Demand mode; no information to transmit¹ Emergency situation report Weather request Weather Cargo information Ground GMT request response Ground UTC request Aircrew initiated voice contact request Alternate aircrew initiated posit. rpt. ATIS request Temporary suspension of ACARS Aircraft initiated position report Weather request Revision to previous ETA Airline designated downlink Aircraft initiated engine data Aircraft initiated misc.message Aircraft addressed downlinks Deliver oceanic clearance Deliver departure clearance Acknowledge PDC Request position report Request ADS report Forward free text to aircraft Deliver departure slot Deliver ATIS information ATIS Facilities notification Request oceanic clearance Request oceanic readback Request departure clearance Ackn. departure clearance Provide position report Provide ADS report Forward free text to ATS Request departure slot Request ATIS information Uplink msg. to all cockpit printers Uplink msg. to cockpit printer #1 Uplink msg. to cockpit printer #2 Uplink msg. to cockpit printer #3 Printer status = error
Introducing ACARS
Label CB ó CC ó CD ó CE ó CF ó F3 ò H1 ô HX ò M1 ò M2 ò M3 ò M4 ò Q0 Q1 ò Q2 ò Q3 ò Q4 ñ Q5 ó Q6 ò Q7 ò QA ò QB ò QC ò QD ò QE ò QF ò QG ò QH ò QK ò QL ò QM ò QN ò QX ò RA ñ RB ò :; ñ
SMI
REJ MVA MVA MVA MVA
ETA CLK
DLA DEP DEP ARR ARR DEP DEP RTN DEP ARR ARR ARR DIV RPR
Message Title Printer status = busy Printer status = local Printer status = no paper Printer status = buffer overrun Printer status = reserved Dedicated transceiver advisory Message to/from terminal Undelivered uplink report IATA Departure message IATA Arrival message IATA Return to ramp message IATA Return from airborne message ACARS link test ETA Departure/arrival reports ETA reports Clock update Voice circuit busy (response to 54) Unable to process uplinked messages Voice-to-ACARS change-over. Delay message Out/fuel report Off report On report In/fuel report Out/fuel destination report Off/destination report Out/return in report Out report Landing report Arrival report Arrival information report Diversion report Intercept Command aircraft term. to transmit data Response of aircraft terminal to RA msg. Command aircraft xcvr to change freq.
¹ These are non-printing characters, and will not be displayed.
Message Direction ò Downlink. ñ Uplink. ô Uplink or downlink. ó Ground to ground. Page 2
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ABBREVIATIONS
0A 0B 0C AL CG CI CL CR CW CZ DA DG DP DS E1-9 EO FB FC FD FF FI FL FO FR FX GL HD IC IN IR LA LT MA MN MT N1 NA NL NP
Passengers in first class Passengers in business class Passengers in coach class Flight level Center of gravity Cost index Cruising level Company route Cruise wind Cruising speed Departure aerodrome Drag factor Dew point Destination station Engine parameters Estimated time over Fuel on board Estimated further clearance Fuel over destination Fuel flow factor in lbs/hr. Flight Identification Flight level First officer Fault report prefix Enroute fix Geographical location Aircraft heading Aircraft icing Time in In range (of VHF radio) ID of officer landing aircraft Light Message assurance Maintenance Maximum takeoff power Speed of turbine 1 Navaid Number of landings Next report point
APRCH ARINC ATISRQ AWDAF AWDFT AWDSA CLIMB CRUISE DESCEN INCLIMB INRANG INRP LEVEL LIVE OFFRP ONRP OUTRP PIREP POSWX TYP 1 UDCST WXRQ
OF ON OP OS OT OV PB PD PW QN RD RF RI RL RM RO RT RL SA SI SK SL SP ST TA TB TD TE TM TO TP V1 VR V2 WI WV WR WX ZW
Time off Time on Oil pressure Other supplementary info. Time out or oil temperature Present location (over) Number of persons on board Point of departure Position weather Altimeter settings Departure runway Request flight level Return in time Requesting cruising level Remarks Return on time Route information Request cruising level Latest weather Special communication Sky conditions Selcal code Significant point Standard takeoff power Static air temperature Turbulence Takeoff temperature Time enroute Surface air temperature Time over Transmission path Velocity 1 Rotate speed (& runway vis rng) Velocity 2 Weather Wind information Warning prefix Weather Zero fuel weight
Approach Aeronautical Radio Inc. ATIS request Auto Wx Data-Area Forecast Auto Wx Data-Terminal Area Forecast Auto Wx Data-Air route Forecast Climbing Cruise level Descending In climb In range of (VHF) In report Level flight Live cargo (animals) Off report On report Out report Pilot's report Position weather Type 1 weather request Undercast sky Weather request
Introducing ACARS
AEP AGM ALT ALT APP AWD BBG BKN CHP CLR CPT CRZ CVG DAI DBI DDG DDX DEV DFR DLD DTX EDA EFC EGT ENG EOK EON EPR ERR ERT FDD FLR FLT FOB FPR FRM FTM LIF LND MCH MEL OCC OFF OUT OVR POS PWD RVR SAT SMI SMT TEI TIS TKO TRB TXT TYP VEC WND WOB WRN WXA WXR
ICAO position report with wx. Start of standard message Altitude Altimeter Approach Automated weather data in reference to HAZMAT cargo Broken Chop Clear Captain Cruise altitude Covering Display aircraft itinerary Data base initialization-update in reference to HAZMAT cargo Display dispatch message Display aircraft deviations Display flight routing in reference to cargo Display text Engine data Expect final clearance Exhaust Gas Thrust Engine data Everything "OK" Expected touchdown time Exhaust pressure ratio Error message Estimated ramp time Flight data recorder info Fault report Flight Fuel on board Flight plan request Maintenance codes used before waypoint name request for Load information Landing Mach (aircraft speed) Minimum essential list Occasional (weather) Off time Out time Over Position Predicted weather data runway visual range Static air temperature Standard message identifiers Standard message text Text element identifiers ATIS information Takeoff Turbulence Text Type Vector Wind (direction/velocity) Weather observation Warning Weather at Weather Page 3
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AIRPORT IDENTIFIERS
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IATA ATL BDL BER BHM BKL BNA BOS CDG CGX CHC CHI CMH CVG DFW DCA DEN DTW EWR FCO IAD JFK LAX LGA LGW LHR MCO MEM MDW MEX MIA MUC MSP MSY NRT NYC OAK ORD ORY PHL PIT PWK SFO SLC STL SNN TPA TPE YYZ
The ACARS system can also be used to passing routine text traffic as in the following example:
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ICAO KATL KBDL EDBB KBHM KCLE KBNA KBOS LFPG KORD NZCH
KCMH KCVG KDFW KDCA KDEN KDTW KEWR KIAD KJFK KLAX KLGA EGKK EGLL KMCO KMEM KMDW MMMX KMIA EDDM KMSP KMSY RJAA KEWR KOAK KORD KPHL KPIT KPWK KSFO KSLC KSTL EIAA KTPA RCTP CYYZ
Airport Atlanta, GA Hartford, CT Berlin, GERMANY Birmingham, AL Cleveland, OH Nashville, TN Boston, MA Paris, FRANCE (de Gaulle) Chicago, IL (Meigs) Christchurch, NEW ZEALAND Chicago, IL Columbus, OH Cincinnati, OH (Covington, KY) Dallas-Ft.Worth, TX Washington, DC (National) Denver, CO Detroit, MI Newark, NJ Rome, ITALY (Da Vinci) Washington, DC (Dulles) New York, NY (Kennedy) Los Angeles, CA New York, NY (La Guardia) London, ENGLAND (Gatwick) London, ENGLAND (Heathrow) Orlando, FL Memphis, TN Chicago, IL (Midway) Mexico City, MEXICO Miami, FL Munich, GERMANY Minneapolis/St. Paul, MN New Orleans, LA Tokyo, JAPAN (Narita) New York, NY (Newark-NJ) San Francisco, CA (Oakland) Chicago, IL (O'Hare) Paris, FRANCE (Orly) Philadelphia, PA Pittsburgh, PA Chicago/Wheeling, IL San Francisco/Oakland, CA Salt Lake City, UT St. Louis, MO Shannon, IRELAND Tampa/St. Petersburg, FL Taipei, TAIWAN Toronto, ON-CANADA
FURTHER READING
PLAIN TEXT MESSAGES
.N908UA ESTIMATING ARRIVAL AFTER CURFEW, LOCAL MANAGEMENT WILL MAKE DECISION WHETHER TO LAND AFTER CURFEW OR DIVERT. THIS INFORMATION WILL BE RELAYED TO FLIGHT ENROUTE BY CHIEF. PENALTY FOR CURFEW VIOLATION WILL BE HANDLED BY LGB. (CHIDD PEK 07/28/ 90)
This message was to a crew who was going to be late in landing at Long Beach. s
AIRLINE CARRIERS
ICAO IATA AAL AA ACA AC AWE HP BAW BA COA CO DAL DL DHL ER FDX MB FTL FT FWL HAL HA IBE IB NWA NW OZA PAI PI QFA QF SWA SR TWA TW UAL UA UPS SX USA US IATA ICAO
Airline American Airlines AirCanada America West British Airways Continental Airlines Delta Airlines DHL Airways Federal Express Corp. Flying Tiger Line Florida West Airlines Hawaiian Airlines Iberia Airlines Northwest Orient Ozark Airlines Piedmont Aviation Quantas Airways Swissair Trans World Airlines United Airlines United Parcel Service U.S. Air
Country U.S.A. Canada U.S.A. U.K. U.S.A. U.S.A. U.S.A. U.S.A. U.S.A. U.S.A. U.S.A. Spain U.S.A. U.S.A. U.S.A. Australia Switzerland U.S.A. U.S.A. U.S.A. U.S.A.
= International Air Transport Association = International Civil Aviation Organization
Understanding ACARS - Third Edition By Ed Flynn This detailed and informative book takes the mystery out of decoding ACARS. (Universal) Price: $ 9.95 The Worldwide Aeronautical Communications Frequency Directory - Second Edition By R.E. Evans The most complete and up-to-date aero frequency directory ever published. Over 2350 frequencies covering voice and data on HF, VHF & UHF. (Universal) Price: $19.95 Introducing ACARS
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