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asr0dzjq
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ICAO codes with repeat letters

Fri Mar 27, 2020 1:56 pm

I've noticed some airports where the ICAO codes have three repeat letters, such as OIII, WIII, ZGGG, ZHHH, ZLLL, ZPPP, ZSSS, ZUUU, ZWWW. Are repeat letters like this supposed to denote the airport of the largest city in the region, or what else do they denote besides the "main" airport (if they do)?
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GalaxyFlyer
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Re: ICAO codes with repeat letters

Fri Mar 27, 2020 3:01 pm

First letter is region, second country, third and fourth whatever the national authority wants. Paris airports are LFPx, x being B for LeBourget, G for DeGaulle, O for Orly.
 
Cubsrule
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Re: ICAO codes with repeat letters

Fri Mar 27, 2020 6:47 pm

GalaxyFlyer is correct. Also note that there are a decent number of airports, especially in the U.K. and Japan, that repeat the last two letters (Narita is RJAA, Haneda is RJTT, Heathrow is EGLL, Gatwick is EGKK, etc.).
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Bellerophon
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Re: ICAO codes with repeat letters

Fri Mar 27, 2020 10:06 pm

As GalaxyFlyer has said, the First letter is Region, the Second letter is Country (and dependencies), and the last two letters are down to the national authority.

In the UK that means E = Northern Europe, then G = Great Britain, followed by two further letters.

However, in the UK, it is not just coincidence that major airfields have a double letter ending. As I understand it, it revolves around the concept of a "Master" airfield in any given area, normally the largest or most important, which was responsible for administrative control and dissemination of information for the smaller, or satellite, airfields around it.

If I remember correctly, in the UK, the Last (4th) letter is the identifier of the individual airfield whilst the Third letter is the identifier of the Master airfield in whose region it is located. It follows that the Master airfield for any UK region will always have the same last two letters at the end.

To take Heathrow (EGLL) as an example, its airfield identifier is the 4th letter "L", however as it is also the Master airfield for the area, its 3rd letter is also "L". Two airfields in the same region I'm familiar with are EGLM (White Waltham) and EGLJ (Chalgrove).

Likewise, if we use Gatwick (EGKK) we can also see EGKR (Redhill) and EGKH (Headcorn) in its area.

I wonder if the Master airfield concept in the UK may have had its origins in the war years with a large number of satellite airfields dispersed around a larger main airfield?

Years ago, when flying non-radio light aircraft out of Redhill - at that time also a non-ATC airfield - Gatwick was the airfield responsible for providing notam and weather information relative to our flights and we would usually telephone them just before departure to check to see if there were any last minute notams or restrictions.

Best Regards

Bellerophon
 
GalaxyFlyer
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Re: ICAO codes with repeat letters

Sat Mar 28, 2020 12:07 am

IIRC, from a similar post on PPRUNE, the third and fourth letter in the UK were related to their telephone switch which goes to your comment on Gatwick and Redhill. The RAF bases certainly appear that way.

https://www.pprune.org/atc-issues/31675 ... stand.html
 
aeropix
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Re: ICAO codes with repeat letters

Sun Mar 29, 2020 7:13 am

I think everyone is missing the OP's point. We all know that there is a "method" or "system" in place to assign the codes, but that is not what he was asking about. There is a bit of discretion in assigning the last two letters. For example Harare, Zimbabwe was FVHA with the last two letters ostensibly for "Harare Airport" and changed to "FVRG" with the last two letters for political leader "Robert Gabriel" Mugabe.

So I do not know exact the answer to OP's question but I think I do understand what is the question, "Why do some countries (particularly China) choose a code with 3 repeating letters when other combinations were available?". Perhaps they have their own local motivations like the politically motivated code change in Zimbabwe. Maybe its "good luck" to have 3 repeating letters / symbols in China? Maybe they just thought it had an appealing "look" (after all the chinese characters are very much more "visual" in nature than our own utilitarian alphabet). None of these or maybe all of these reasons could be correct.
 
GalaxyFlyer
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Re: ICAO codes with repeat letters

Sun Mar 29, 2020 1:40 pm

Because they can.......that’s the answer. Doesn’t matter beyond that.
 
VSMUT
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Re: ICAO codes with repeat letters

Sun Mar 29, 2020 2:39 pm

There is no universal system apart from the first 2 letters. Some are random, some are sort of abbreviations of the city they serve, some are designated for historical reasons. Depends entirely on the country and the mood of the regulators when they came up with the system.

EKYT - Aalborg. YT stands for Yellow Target, apparently the WWII allied designation for the (then) Luftwaffe airbase.
LSZH - ZH = Zürich.
CYYZ - Toronto. Seems completely random to me.
 
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SheikhDjibouti
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Re: ICAO codes with repeat letters

Sun Mar 29, 2020 10:28 pm

VSMUT wrote:
There is no universal system apart from the first 2 letters. Some are random, some are sort of abbreviations of the city they serve, some are designated for historical reasons. Depends entirely on the country and the mood of the regulators when they came up with the system.

EKYT - Aalborg. YT stands for Yellow Target, apparently the WWII allied designation for the (then) Luftwaffe airbase.
LSZH - ZH = Zürich.
CYYZ - Toronto. Seems completely random to me.
I'm going to pick up on that last one, not because I have any special knowledge, but because it interests me.
(I should perhaps add that I had some interest in radio callsigns and QSL cards)

Although "C" is allocated to Canada, in practice, airport codes are all either CYxx or CZxx.
(Likewise aircraft registrations are currently limited to C-Fxxx and C-Gxxx, with the alarming possibility that the next sequence to be employed will be C-Ixxx which was reserved back in 1974. Quite why C-Hxxx has been skipped is another puzzle)

Since Toronto has more than one airport, YTO is used for the area designation.

The telegraph station in Toronto itself was coded TZ, which is why Toronto's City Centre Airport (Billy Bishop) is coded YTZ / CYTZ

Likewise the station in Malton, Ontario (where Pearson Airport is located) was YZ, and hence the code for Pearson Airport is YYZ / CYYZ

Why was Malton "YZ" instead of "MA" ? At a wild guess, "MA" had already been taken by another station e.g. Mayo, Yukon.

As you say; "some [codes] are random"
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rfields5421
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Re: ICAO codes with repeat letters

Sun Mar 29, 2020 10:37 pm

Airport codes started because of the code of the radio station at the airport.

Remember ICAO and attempts at global standardization related to aviation became a significant goal during and after WWII.

Like many things in the age of industrialization, the system just 'grew' as needs expanded. Radio was new and standardization of their identification system was started before aviation began to start to standardize.

For airports some nations chose to revamp their system completely, and many others just made minimal modifications to match the new ICAO standards. There are thousands of airports in the United States without ICAO codes, using older FAA, and in come cases CAA or CAB assigned identification, admittedly very small fields in most cases.

Aviation is still a relatively 'new' technology. There is still at lest one person alive today who was born before the Wright Brothers made their first powered flight.
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VSMUT
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Re: ICAO codes with repeat letters

Mon Mar 30, 2020 7:24 am

SheikhDjibouti wrote:
VSMUT wrote:
There is no universal system apart from the first 2 letters. Some are random, some are sort of abbreviations of the city they serve, some are designated for historical reasons. Depends entirely on the country and the mood of the regulators when they came up with the system.

EKYT - Aalborg. YT stands for Yellow Target, apparently the WWII allied designation for the (then) Luftwaffe airbase.
LSZH - ZH = Zürich.
CYYZ - Toronto. Seems completely random to me.
I'm going to pick up on that last one, not because I have any special knowledge, but because it interests me.
(I should perhaps add that I had some interest in radio callsigns and QSL cards)

Although "C" is allocated to Canada, in practice, airport codes are all either CYxx or CZxx.
(Likewise aircraft registrations are currently limited to C-Fxxx and C-Gxxx, with the alarming possibility that the next sequence to be employed will be C-Ixxx which was reserved back in 1974. Quite why C-Hxxx has been skipped is another puzzle)

Since Toronto has more than one airport, YTO is used for the area designation.

The telegraph station in Toronto itself was coded TZ, which is why Toronto's City Centre Airport (Billy Bishop) is coded YTZ / CYTZ

Likewise the station in Malton, Ontario (where Pearson Airport is located) was YZ, and hence the code for Pearson Airport is YYZ / CYYZ

Why was Malton "YZ" instead of "MA" ? At a wild guess, "MA" had already been taken by another station e.g. Mayo, Yukon.

As you say; "some [codes] are random"


What about Montreal, CYUL?
 
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SheikhDjibouti
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Re: ICAO codes with repeat letters

Mon Mar 30, 2020 1:14 pm

SheikhDjibouti wrote:
VSMUT wrote:
There is no universal system apart from the first 2 letters. Some are random, ....
Although "C" is allocated to Canada, in practice, airport codes are all either CYxx or CZxx.

VSMUT wrote:
What about Montreal, CYUL?
Sounds like a typical Canadian farewell

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26point2
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Re: ICAO codes with repeat letters

Wed Apr 01, 2020 3:29 am

Bellerophon wrote:

To take Heathrow (EGLL) as an example, its airfield identifier is the 4th letter "L", however as it is also the Master airfield for the area, its 3rd letter is also "L". Two airfields in the same region I'm familiar with are EGLM (White Waltham) and EGLJ (Chalgrove).


Also EGLF- London Farnborough.
 
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SheikhDjibouti
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Re: ICAO codes with repeat letters

Wed Apr 01, 2020 1:59 pm

26point2 wrote:
Bellerophon wrote:
To take Heathrow (EGLL) as an example, its airfield identifier is the 4th letter "L", however as it is also the Master airfield for the area, its 3rd letter is also "L". Two airfields in the same region I'm familiar with are EGLM (White Waltham) and EGLJ (Chalgrove).

Also EGLF- London Farnborough.
And EGLA - London Bodmin (just across from Jamaica Inn) :duck:

(for those who don't get the joke, Bodmin airfield is in fact located on Bodmin Moor many many miles from London. It is also not very from the somewhat famous Jamaica Inn, and other interesting features of Cornwall such as Brown Willy)

To be fair, many of the EGLx are London-ish.

EGLC (LCY) London City
EGLD Denham
EGLT Ascot Racecourse

But Chalgrove is hardly London, not when compared to
EGTB Wycombe Air Park
EGGW London Luton
EGKB London Biggin Hill (possibly in the "Kx group due to its' "proximity" to Gatwick?)
Nothing to see here; move along please.

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