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4 Letter Idents I.e. MRDK, Mrce?

Wed Jan 22, 2003 2:01 pm

Just curious as to the story on 4 letter versus normal 3 idents i.e. MRDK -Drake Bay Costa Rica, and MRCE Carate, Costa Rica. These stuck out in my a/c aids.

Are there any others in N.A.?? I have looked in my Aircrew Aids and can't find any.

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Wed Jan 22, 2003 6:50 pm

Every airport with airline service has a four letter identifier. For local use the three letter is more common - but when I enter origin and destination airports in the FMS in the 767, I have to enter the four letter ICAO designator.

The first (and sometimes first & second) letter designates the country and/or region the airport is in. For instance, all the airports in the mainland US start with "K". So Los Angeles (familiar to most as LAX) is KLAX, San Francisco is KSFO. Airports in the Pacific start with "PH". Honolulu (HNL) is PHNL, Maui (OGG) is PHOG. Airports in Alaska start with "PA". Anchorage is PANC, Fairbanks is PAFA. In your example is appears the code for Costa Rica is "MR".

You might be able to find more info on the ICAO (International Civil Aviation Organization) web site. It's at

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Wed Jan 22, 2003 8:15 pm

Over here in Europe the ICAO codes are (generally speaking) split as such:

1st letter - Northern Europe (E) or Southern Europe (L)
2nd letter - Country
3rd & 4th letters - Airport

So for example, LEMG is Malaga (AGP). Lower Europe, Spain (Espana), MalaGa.

EHAM is Amsterdam (AMS). Northern Europe, Holland, AMsterdam.

LPFR is Faro (FAO). Lower Europe, Portugal, FaRo.

Easy huh? As pilots we are generally uninterested in 3-letter (IATA) codes. FMCs, weather reports, NOTAMS etc... all refer to the 4-letter ICAO designators only.
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RE: 4 Letter Idents I.e. MRDK, Mrce?

Wed Jan 22, 2003 9:44 pm


Actually I would not make the "difference" calling the three-letter codes "normal".

Both the 3- and 4-letter ones are normal.

The 3-ones are IATA, thus better known by travel agencies and on the "ground side" of the airports.

The 4-ones are ICAO, thus, better known by navigators (pilots) and on the "air-side" of the airports.

For the ICAO codes, they are grouped by areas, and in each area, by countries.

For example, all northenr european airports have "E", followed by B in Belgium, by E in Estonia, by G in UK, etc.

So, take for example London. While for IATA your agent can look up LON (the code for the city as a destination), the computer response will turn out LGW (Gatwick), LHR (Heatrhow), LTN (Lutton), STD (Stansted) or City Center (LCY)

If you choose to fly to Heathrow, your luggage is going to be tagged LHR, but your captain is going to fly to EGLL, while if you choose Gatwick, your luggage will be tagged LGW but the flight plan will be destination EGKK.

Following, alll southern european ones have "L", followed by F in France, by E in Spain, by G in Greece.

Australia has a "Y" for herself alone. For not makin' it too long, let's finish with the South American S, followed by A in Argentina, B for Brazil, G for paraguay etc.

Whenever you come to Barcelona, Europe, your ticket will write BCN, although the crew will ask meteorological infomation on LEBL, while if the Barcelona you fly to is in Venezuela you'll see about BLA but the flight plan about SVBC.

Some examples:

London (as a destination city): LON
London Gatwick: LGW-EGKK
London Stansted: STD-EGSS
London Heathrow: LHR-EGLL
London City Center: LCY-EGCY

City of Paris: PAR
Paris Charles de Gaulle: CDG-LFPG
Paris Orly: ORY-LFPO
Mulhouse: MUL-LFGB

City of São Paulo: SAO
São Pauol Congonhas: CGH-SBSP
São Paulo Guarulhos: GRU-SBGR
City of Rio de Janeiro: RIO
Rio de Janeiro Galeão: GIG-SBGL
Rio de janeiro Santos Dumond: SDU-SBRJ
Brasilia: BSB-SBBR
Goiânia: GYN-SBGO
Aracaju: AJU-SBAR
Fortaleza: FOR-SBFZ
Salvador: SSA-SBSV

Sydney: SYD-YSSY
Melbourne: MEL-YMML

Athens: ATH-LGAT (when the old Hellinikon Airport was operative)
LGAV (The new Eleftherios Venizelos at Spata)

Barcelona: BCN-LEBL
Girona: GRO-LEGE
Palma de Mallorca: PMI-LESJ
Eivissa (in spanish Ibiza): IBZ-LEIB
Madrid: MAD-LEMD
Jerez de la Frontera (in English "Sherry"): XRY-LEJR
Sevilla: SVQ-LEMO
Málaga: AGP-LEMG

It happens, though, that Canadian and continental USA airports are mostly coincident, adding a "C" for Canada and a "K" for USA, this way:

Vancouver: YVR-CYVR
Montréal: YUL-CYUL
Québec: YQB-CYQB
Ottawa: YOW-CYOW
Edmonton: YEG-CYEG
Halifax: YAW-CYAW

New York: NYC
New York Jonh Fitzgerald Kennedy: JFK-KJFK
New York Newark: EWR-KEWR
New York La Guardia: LGA-KLGA
Atlanta: ATL-KATL
Dallas: DFW-KDFW
Chicago: ORD-KORD
Los Angeles: LAX-KLAX

etc., etc., etc.

Basically the main areas are:
A SW Pacific (+G Solomon; +N Nauru; etc.)
B Arctic Circle (+G Greenland; +I Iceland)
C Canada
D West Africa (+A Algeria, +B Benin; +N Nigeria, etc)
E Northern Europe (+B Belgium, +H Netherlands, +K Denmark, etc.)
F, G and H Africa (as a note, Canary Islands are not LExx, but GCxx)
L Southern Europe (+E Spain, +C Cyrpus, +G Greece, +J Slovenia, etc)
M Central America (+D Dominican Republic, +K Jamaica, +Y Bahamas, etc)
N Southern Pacific (+C Cook Islands, +F Tonga, +F Fiji, etc)
O Middle East (+A Afghanistan, +J Jordan, etc)
P Northern Pacific (+H Hawaii, +A Alaska, etc)
R Pacific Asia (+C China, +J, +O Japan, +K Korea, etc)
S South America (+A Argentina, +B Brazil, +Chile, +K Colombia, etc)
T Caribbean (+N Netherlands Antilles, +R Montserrat, +J Puerto Rico, etc)
U Russian Federation including some former Sovietic republics
(+A Kazakhstan+Kyrzighistan; +B Azerbaitjan, +G Armenia+Georgia, +K Ukraine)
(UE, UH, UI, UL, UM, UN, UO, UR, US Russia)
V Continental Asia (including +H Hong Kong, +A; +E, +I, +O India, +D Cambodia)
W South Eastern Asia (+A, +I, +R Indonesia, +B Brunei, etc)
Y Australia
Z China
Hope I helped.

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Wed Jan 22, 2003 11:50 pm

Every airport with airline service has a four letter identifier

That is not entirely true, as every single airfield will have the 4 letter ICAO code, while only commercial airports are bound to have a 3 letter IATA code.

For instance, in the small town of Chambery (France) where I live, we have 2 airfields. One of those has commercial service : Chambery/Aix les Bains - Voglans, then additionally to the ICAO code 'LFLB', it also have the IATA code 'CMF'
We have a second airfield, just a few miles away, used only by gliders and light aircrafts. No commercial service there, so no IATA code. Only LFLE (Chambery-Challes les Eaux).

Hope I was not too confusing...

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Wed Jan 22, 2003 11:59 pm

Some airports even have 2 IATA codes, e.g. Amsterdam Schiphol: AMS/SPL.

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Thu Jan 23, 2003 2:17 am

THanks for the replies, though I know all about the ICAO codes, I have been flying as crew, pilot, and pax for many years, taht wasn't the question per se, but why these two list as four instead of 3 (minus the country code of Costa Rica), adding that would make it 5 letters instead of the normal 4. Make sense.

Turbulence I have a/c aid with a similar list to yours, but it doesn't explain what I am seeing with jsut these two listed as 4 with all the others as 3, our flight computers won't even take the imputs

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Thu Jan 23, 2003 4:11 am

Idents with numbers in them (i.e. 52F) I don't believe are prefixed with a "K" in the U.S.
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RE: 4 Letter Idents I.e. MRDK, Mrce?

Thu Jan 23, 2003 11:41 am


Landed there last week. Nice little airport, and the closest to the Texas Motor Speedway.

Now that's obscure!

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Thu Jan 23, 2003 9:07 pm

OK, maybe (as usual) o wrote too much from the very beginning... Ah!! this "writorrhea" of mine!!!

What you say could possibly be, as you refer to nav-aids, that not everything appearing in that map were airports, but some radio aids, VORs and/or passing points...

As written, Barcelona has IATA code BCN, and ICAO code LEBL.

I know for sure that there's another reference to Barcelona for navigation purposes, thus NOT NECESSARILY for landing there, but for navigation too (airplanes crossing above Barcelona at cruising altitude, let's say, for example a flight Frankfurt-Madrid). In this case, such an airplane will never have Barcelona referred to as BCN neither LEBL.

Their clue above us or while in the area of Barcelona Radar will be QUV, which is the code referring to the VOR that geographically localizes Barcelona en route.

I know, then, that around Barcelona there are other aids (don't ask me if they are VORs or not). Some of them are TEBLA and TOLSO, that DO NOT correspond to any geographic name. This makes me think of 5-letter codes.

Some others are referred to geographic places, like, among others, Castejón (CJN), Maella (MLA), Villanueva and Sabadell, of which codes I'm not sure, used as reference while in approach procedures for landing at, or departing from, Barcelona.

Sabadell is also an airfield, whose ICAO code is LELL, obviously for departing and/or destination purposes to there, not for navigation aids.

Hope to have been more useful this time...

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RE: 4 Letter Idents I.e. MRDK, Mrce?

Fri Jan 24, 2003 4:56 am

Jhooper is correct, in the US if an airport has a number in its 3 character cod then there is no four letter code with a K attached...

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