VAF Forums - Okay, why the 'K'

VAF Forums (https://vansairforce.net/community/index.php)

- GPS (https://vansairforce.net/community/forumdisplay.php?f=39)

- - Okay, why the 'K' (https://vansairforce.net/community/showthread.php?t=20071)

Okay, why the 'K'

This is not exactly GPS specific but since it causes me grief on my Lowrance 1000, I am posting here.

Why do some airport identifiers need a 'K' prefix when searching for an airport by identifier? For example, my home airport identifier is 'CIC' on the Sacremento sectional and facility guide but if I search my GPS for 'CIC', it will not find it. You must enter 'KCIC'. This can and has doubled my heads down time.

I initially thought it might be related to size of the airport or VOR on the field but that does not seem to be the case.

Lowrance if you are listening, a useful feature would be to add a prompt along the lines of "Did you mean KCIC?" when "CIC" is entered.

Somewhere back in the dark recesses of my poor old brain, I seem to remember it has to do with international stuff. All U.S. is "K"

Check your GPS setup... you might be able to set it up so that a "K" is assumed as the first letter of an airport designator if only 3 letters are used...

My old Apollo GX-55 does this.... saves a little time entering stuff... :)

gil in Tucson

'K' is one of the internation prefixes assigned to the US. All radio stations in the US begin with either a W, A, N, or K.

Civil aircraft begin with the letter 'N'.

The 'K' when used with an airport code is actually a weather station designator. Hence, small airports without an 'official' weather service feed do not have the letter 'K'.

GPS's use it because an airport identifier is not necessarily unique to the US, so the 'K' indicates that it is a US location. Also applies to radio navigation identifiers.

Be careful if you're GPS does not require the 'K'.... could be confusing when the direct to shows the next waypoint at 6719 nautical miles!

Basic rule of thumb...if the identifier has 3 letters, use the K prefix. If it has any numbers in it, leave the K off.

If you enter your airport ID without the 'K' and your GPS requires the K for specific distinction, you will be entering the identifier for a NAVAID. Example: Here at Sheppard AFB, TX the field identifier is KSPS, however the associated VORTAC is SPS which is located 5 miles west of the airport. Granted you're close to the field but if the WX is hazy or you really need it to find the airport (anyone land at Twin Oaks in San Antonio lately? Without GPS I'd still be looking for it even on a clear day!) you probably won't.

So, the K tells the GPS that you are indeed looking for the airport and not the navaid.

And to add to an earlier post, some airports only have 3 alpha numeric ID but they are, as noted, without WX info and usually have letter(s) and numbers. As has happened at Kickapoo airport her in Wichita Falls, it recently got WX reporting and their ID changed from a 3 alpha numeric ID to a K prefix + 3.

Tailwinds

I fly into many airports that have a K that don't have an ASOS or AWOS on the field. What I have seen in the last few years is that when an airport, let's say Graham, TX, gets an ASOS. Their designator was E15. When the ASOS or AWOS was activated it became KRPH.
Now, in my Lowrance 2000c, in I say find KADM it's going to take me to Ardmore Municipal located a few miles east of town. If I punch in ADM it's going to put me right over the top of the Ardmore VOR, closer to the north of town and a good ways from the airport.
So, know your unit and be careful out there. First and foremost, read the operator's manual. Lowrance explains it very clearly in the instructions.

Knob selection....

Quote:

Originally Posted by Jetj01

Depends on the GPS... with the Apollo, a knob selects "airport" and then the "K" is not needed. This prevents the navaid from being selected.

Check your specific GPS setup...

gil in Tucson

Notwithstanding the GPS issues, here's the actual reasons for the K or lack thereof:

http://www.faa.gov/airports_airtraff...bs/LID/CH1.htm

Bottom line: they get a K if they have (1) manned ATC, (2) a navaid on the field, (3) scheduled air carrier or military airlift service, or (4) they're an airport of customs entry. And, (5) certain weather reporting stations.

Quote:

a. Three-letter identifiers are assigned as radio call signs to aeronautical navigation aids; to airports with a manned air traffic control facility or navigational aid within airport boundary; to airports that receive scheduled route air carrier or military airlift service, and to airports designated by the U.S. Customs Service as Airports of Entry. Some of these identifiers are assigned to certain aviation weather reporting stations.

Quote:

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.

e. Two-letter, two-number identifiers are assigned to private-use landing facilities in the United States and its jurisdictions which do not meet the requirements for three-character assignments. They are keyed by the two-letter Post Office or supplemental abbreviation (listed below) of the state with which they are associated. The two letter code appears in the first two, middle, or last two positions of the four character code.

Quote:

1-4-1 Use of Location Identifiers: An international location indicator is a four-letter code used in international telecommunications. The location indicator for airports in the contiguous United States is the three-letter identifier preceded by "K". For other non-contiguous United States airports, the following two letter prefix will be used...

K in identifiers

All US airports I've encountered with an alpha ident begin with K and Garmin's literature says this is so. If the airport's identifier begains with a letter, the K should be added to the beginning of the ident. All airports (private or public) whose identifier begins with a number do not require or have the K. I don't know where this is spelled out in the regs but it's consistent with everything I've found in Loran and GPS databases and at all airports where we've landed or visited. Hope this helps. Bill