Airport Identifier Logic

[Jay Honeck]

In another thread, someone mentioned that only 13% (or something like that)
of the possible 3-letter combinations are currently used as airport
identifiers. Given this fact, why in the world did they start mixing
numbers into the scene?

For example, why "C89" (for Sylvania Field, in WI) instead of some letter
combo?

Anyone know why the identifiers are a mix of letters and numbers the way
they are?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Richard Russell]

On Tue, 12 Aug 2003 18:59:12 GMT, "Jay Honeck"
> wrote:

>In another thread, someone mentioned that only 13% (or something like that)
>of the possible 3-letter combinations are currently used as airport
>identifiers. Given this fact, why in the world did they start mixing
>numbers into the scene?
>
>For example, why "C89" (for Sylvania Field, in WI) instead of some letter
>combo?
>
>Anyone know why the identifiers are a mix of letters and numbers the way
>they are?


I don't know the answer to that question but I am very intrigued
myself. I always wondered if there was any significance to the type
of designation. This curiosity rose to a new level when the airport
closest to my house (where I hang out and watch for hours but don't
fly out of) had their designation changed from N67 to KLOM.

This change in designation came after a runway rebuild (and extension)
and the installation of an AWOS. That led me to question whether the
type of designation is determined by the level of facilities that are
offered. Hope somebody knows.
Rich Russell

[Ron Natalie]

"Jay Honeck" > wrote in message news:4Oa_a.128203$o%2.55258@sccrnsc02...
> In another thread, someone mentioned that only 13% (or something like that)
> of the possible 3-letter combinations are currently used as airport
> identifiers. Given this fact, why in the world did they start mixing
> numbers into the scene?
>
Back in the old days, for small airports, they used to use a letter corresponding
to the FAA district and numbers. Hence you've got a lot of Wxx airports in the
DC area, etc... Now the official nomenclature for airports that don't need an
ICAO compliant designator is to use the state postal letters. I'm sure Steve
can dig up the official FAA doc on facility nomenclature.

Remember that the airport ID shares space with NAVAIDS as well.

[Ron Natalie]

"Richard Russell" > wrote in message ...
This curiosity rose to a new level when the airport
> closest to my house (where I hang out and watch for hours but don't
> fly out of) had their designation changed from N67 to KLOM.
>
> This change in designation came after a runway rebuild (and extension)
> and the installation of an AWOS. That led me to question whether the

It was the AWOS that did it. Weather reporting facilities have to have ICAO
compliant (no numbers) identifiers. This was more lipservice by the FAA to
ICAO standardization when they switched to METAR/TAF. Of course, the
METAR/TAF deviates from the ICAO version, but what the hey.

[David Megginson]

"Ron Natalie" > writes:

> Remember that the airport ID shares space with NAVAIDS as well.

That's getting better, though, as more and more people are switching
to the four-letter ICAO IDs for airports, leaving three-letter IDs for
navaids and five-letter IDs for intersections. For example, the
co-pilot database on my Palm "YSH" for the Smith's Falls NDB and
"CYSH" for the Smith's Falls airport; "YOW" for the Ottawa VOR and
"CYOW" for the Ottawa Airport; and so on.


All the best,


David

--
David Megginson, , http://www.megginson.com/

[Greg Burkhart]

"Jay Honeck" > wrote in message
news:4Oa_a.128203$o%2.55258@sccrnsc02...
> In another thread, someone mentioned that only 13% (or something like
that)
> of the possible 3-letter combinations are currently used as airport
> identifiers. Given this fact, why in the world did they start mixing
> numbers into the scene?
>
> For example, why "C89" (for Sylvania Field, in WI) instead of some letter
> combo?
>
> Anyone know why the identifiers are a mix of letters and numbers the way
> they are?

I had wondered this too. Doing a search, I found:
http://www2.faa.gov/atpubs/LID/ch1.htm
----
(Clipped from the doc):
c. Most one-number, two-letter identifiers have been assigned to aviation
weather reporting and observation stations and special-use locations. Some
of these identifiers may be assigned to public-use landing facilities within
the United States and its jurisdictions, which do not meet the requirements
for identifiers in the three-letter series. In this identifier series, the
number is always in the first position of the three-character combination.

d. Most one-letter, two-number identifiers are assigned to public-use
landing facilities within the United States and its jurisdictions, which do
not meet the requirements for identifiers in the three-letter series. Some
of these identifiers are also assigned to aviation weather reporting
stations.

1. One-letter, two-number identifiers are keyed by the alphabetical
letter. The letter may appear in the first, middle or last position in the
combination of three characters. When the letter signifies an Air Traffic
Control Center's area, the assignment will not change if the Center's
boundaries are realigned.
----

Some identifiers make some sense:
DSM, OKC, IOW, MSP, SIN...

Some don't:
PWA, MFE, EOK, CID, AXA, JYG, CVG...

It's "usually" smaller airports with the numbers:
Y58, 0K7...
Sometimes the Zero and "O" are difficult to distinguish between:

I know one airport that did want to change its identifier: SUX.
The English translation of Notams sometimes translates the Fort Dodge
airport identifier (FOD) as Foreign Object Damage.

[Wally Samuelson]

First I am using Outlook Express and I can't figure out how to reply with
out repeating the previous post. If anyone can help please advise me.

It occurs to me that 1984 has come and gone and poor old George Orwell, the
originator of "Newspeak" is whirling in his grave.

In the last couple of posts I have seen FAA, Wxx, DC, ICOA, ID, NAVAIDS,
AWOS, and what on earth is a METAR/TF?

Most of these others I THINK I understand, but not sure about AWOS and ICAO.

I did do a little reasearch. One data base I checked said there were about
9000 three letter codes in use. 26 cubed is 17,576 possible combinations, so
that is a little more than half. If you add the country code then
26/4th is 456,976 possibilities, so I don't think we will run out soon.

Most of the airport codes seem to try to be mnemonic, but the reasoning can
be a little deep. PWA for instance is Wiley Post Airport in Oklahoma City,
OKC where the main airport is Will Rogers Internatiional.

EOK Is Keokuk. Makes sense. CID Cedar Rapids. CVG is my favorite. Greater
Cncinnati, OH airport, located in Covington, KY. Get it now?

SEA is another. Think it means Seattle? No Way. Means SEA-TAC which
actually lies within the boundries of the City of Sea-Tac, Washington, about
half way between Seattle and Tacoma

Incidentally there was a big row up there a few years ago when Seattle
unilaterally changed the name to Jackson International in honor of their
congressman. They had to back down when Tacoma raised the roof about that
one.

Anyway, some random trivia about airport names and codes.

Wally
There are old pilots, and bold pilots
but there are no old, bold pilots.
I turned 81 yesterday


"Jay Honeck" > wrote in message
news:4Oa_a.128203$o%2.55258@sccrnsc02...
> In another thread, someone mentioned that only 13% (or something like
that)
> of the possible 3-letter combinations are currently used as airport
> identifiers. Given this fact, why in the world did they start mixing
> numbers into the scene?
>
> For example, why "C89" (for Sylvania Field, in WI) instead of some letter
> combo?
>
> Anyone know why the identifiers are a mix of letters and numbers the way
> they are?
> --
> Jay Honeck
> Iowa City, IA
> Pathfinder N56993
> www.AlexisParkInn.com
> "Your Aviation Destination"
>
>

[Greg Burkhart]

----- Original Message -----
> First I am using Outlook Express and I can't figure out how to reply with
> out repeating the previous post. If anyone can help please advise me.

Using Outlook Express, just select the parts of the previous message you
don't want repeated and delete it.

> Most of the airport codes seem to try to be mnemonic, but the reasoning
can
> be a little deep. PWA for instance is Wiley Post Airport in Oklahoma City,
> OKC where the main airport is Will Rogers International.
^^^ (Will Rogers WORLD Airport)

I flew out of OKC as an airline passenger many times, a few times
(indirectly) to SIN. I did my flight training at PWA. That's why I listed
those...

> EOK Is Keokuk. Makes sense. CID Cedar Rapids. CVG is my favorite.
Greater
> Cincinnati, OH airport, located in Covington, KY. Get it now?

These are ones that I'm familiar with too. A lot of 3-letter identifiers
make 'some' sense but I haven't figured out how Carroll, IA got CIN (C for
Carroll, I for Iowa and N for Neu?), MFE (McAllen Miller International) and
also JYG... The identifiers with numbers make even less sense...

-Greg Burkhart
Living near JYG
Plane at Y58

[Robert M. Gary]

"Jay Honeck" > wrote in message news:<4Oa_a.128203$o%2.55258@sccrnsc02>...
> In another thread, someone mentioned that only 13% (or something like that)
> of the possible 3-letter combinations are currently used as airport
> identifiers. Given this fact, why in the world did they start mixing
> numbers into the scene?
>
> For example, why "C89" (for Sylvania Field, in WI) instead of some letter
> combo?

Because it doesn't report weather.

[Steven P. McNicoll]

"Greg Burkhart" > wrote in message
news:S9f_a.130591$uu5.18889@sccrnsc04...
>
> These are ones that I'm familiar with too. A lot of 3-letter identifiers
> make 'some' sense but I haven't figured out how Carroll, IA got CIN (C for
> Carroll, I for Iowa and N for Neu?), MFE (McAllen Miller International)
and
> also JYG... The identifiers with numbers make even less sense...
>

Can you think of more logical combinations that fit the criteria and are not
in use?

[Greg Burkhart]

"Steven P. McNicoll" > wrote in message
link.net...
>
> "Greg Burkhart" > wrote in message
> news:S9f_a.130591$uu5.18889@sccrnsc04...
> >
> > These are ones that I'm familiar with too. A lot of 3-letter identifiers
> > make 'some' sense but I haven't figured out how Carroll, IA got CIN (C
for
> > Carroll, I for Iowa and N for Neu?), MFE (McAllen Miller International)
> and
> > also JYG... The identifiers with numbers make even less sense...
> >
>
> Can you think of more logical combinations that fit the criteria and are
not
> in use?

How about CRL, MCA and SJM for these?

[Steven P. McNicoll]

"Greg Burkhart" > wrote in message
news:ylg_a.131184$uu5.18788@sccrnsc04...
>
> How about CRL, MCA and SJM for these?
>

CRL is in use, it's Carleton VORTAC, MI. MCA and SJM are unassigned, but
note that one of the criterion (one that is rather frequently ignored) is
that the first and second letters or second and third letters or third and
first letters of a three-letter identifier may not be duplicated with less
than 200 nautical miles separation. Would assigning MCA to McAllen or SJM
to St. James require such duplication?

[Paul Tomblin]

In a previous article, David Megginson > said:
>That's getting better, though, as more and more people are switching
>to the four-letter ICAO IDs for airports, leaving three-letter IDs for
>navaids and five-letter IDs for intersections. For example, the
>co-pilot database on my Palm "YSH" for the Smith's Falls NDB and
>"CYSH" for the Smith's Falls airport; "YOW" for the Ottawa VOR and
>"CYOW" for the Ottawa Airport; and so on.

Yeah, but I just copied that idea from Garmin, who use K at the beginning
of the ident to distinguish US airports from similarly named navaids.
However, I refused to copy their habit of putting K at the beginning of
ids for airports that shouldn't have K for an ICAO code. For instance,
Alaska, Hawaii and Puerto Rico don't use K, they use P and another letter.
And it's not a simple translation like it is in the continental US. I've
had fits trying to get that mapping correct.

Some software will quite happily accept a psuedo ICAO identifier where
they've just stuck a K willy nilly on airport identifiers with digits in
them. I don't do that.

--
Paul Tomblin >, not speaking for anybody
This is your Air Force: http://www.af.mil/ This is your Air Force on drugs:
http://www.cnn.com/2003/US/01/02/mistaken.bombing/index.html
Any questions?

[David Megginson]

(Paul Tomblin) writes:

> Yeah, but I just copied that idea from Garmin, who use K at the
> beginning of the ident to distinguish US airports from similarly
> named navaids.

The Canada Flight Supplement has also gone to four-letter identifiers
for all airports. The GPS age will probably hasten this change along
everywhere, since it effectively gives airports their own namespace.


All the best,


David

--
David Megginson, , http://www.megginson.com/

[Scott Lowrey]

"Ron Natalie" > wrote in message

> METAR - The ICAO established format for transmittig surface weather observations

METAR - MESSAGE MÉTÉOROLOGIQUE RÉGULIER POUR L'AVIATION Hmm. I can't
see how they got METAR from that, but it's supposedly where the term
came from.

Love those acronyms. It's all part of the "secret language". :~)

-Scott

[Steven P. McNicoll]

"Greg Burkhart" > wrote in message
news:FLh_a.132210$YN5.89274@sccrnsc01...
>
> It doesn't seem always true, (frequently ignored?).
>

Frequently ignored.


>
> CIN to CID is 137.7nm, 6k7 to 0k7 is 66.1nm and FOD to FSD is
> 127.7nm... Just a few local ones that I looked up quickly.
>

6K7 and 0K7 are not three-letter identifiers.

[gpsposter]

> EOK Is Keokuk. Makes sense. CID Cedar Rapids. CVG is my favorite.
> Greater Cncinnati, OH airport, located in Covington, KY. Get it now?


Actually, while Greater Cincinnati airport does use the CVG designation to
stand for Covington, it is actually about 5-10 miles from Covington. It is
actually located in Hebron, KY. I think they used the CVG designation
because Covington was the closest city of a certain size, although most
Cincinnatians (at least those on the Ohio side) think of Covington as just
another suburb of Cincinnati.

[John Harper]

Maybe it deliberately stand for anything. I'm sure many of you have heard
of ISO, the standards body. What does it stand for? International
Standards Organization? Wrong. It's the International Organization for
Standardization. And in French, l'Organization Internationale pur la
Normalization. In other words the acronym deliberately stands for
neither.

John

"Dennis O'Connor" > wrote in message
...
> Nyaaa, the guy in charge of that has a sense of humor and was an Edgar
Rice
> Burroughs fan... It comes from, "ME TARzan, you jane... "
>
> "Ron Natalie" > wrote in message
> m...
> >
> > "Scott Lowrey" > wrote in message
> om...
> > > "Ron Natalie" > wrote in message
> > >
> > > > METAR - The ICAO established format for transmittig surface weather
> observations
> > >
> > > METAR - MESSAGE MÉTÉOROLOGIQUE RÉGULIER POUR L'AVIATION Hmm. I can't
> > > see how they got METAR from that, but it's supposedly where the term
> > > came from.
> >
> > I don't think METAR is an acronym so much as a made up word. METAR is
> rougly
> > pronounceable in most of the member languages.
> >
> >
>
>