Section 2. Location Identifiers System Administration

  1. USE OF LOCATION IDENTIFIERS

The FAA location identifier is an assigned code used to simplify the identification of a landing facility, navigational aid, weather station or manned air traffic control facility.

  1. ASSIGNMENT AUTHORITIES
  1. The Federal Aviation Administration assigns three-letter identifiers (except those beginning with the letters N, W, Y, and Z), three and four character identifiers, and five-letter name codes for the United States and its jurisdictions.
  2. The Department of Navy assigns three-letter identifiers beginning with the letter N for the use of that Department.
  3. Transport Canada assigns two, three, and four character identifiers, including three letter identifiers beginning with letters Y and Z, for its areas of jurisdiction.
  4. The Federal Communications Commission assigns identifiers beginning with K and W for broadcast radio and television stations.
  5. The block beginning with the letter “Q” is under international telecommunications jurisdiction and is used by FAA Technical Operations to capture National Airspace equipment not published in this order.
  6. FAA assigns identifiers beginning with the letter “Z" to air route traffic control centers.
  7. The National Weather Service assigns four-letter, one-number identifiers for certain weather requirements.
  8. The U.S. Air Force Weather Agency (AFWA), acting on behalf of all the military services, assigns three letter FAA identifiers beginning with the letter “Q” for special use by deployed units supporting real world contingencies; deployed/in-garrison units providing support during exercises; supporting weather system testing programs requiring temporary station identifiers; and units that have requested, but not yet received a permanent location identifier.
  9. The Air Traffic Safety Oversight (AOV) assigns identifiers within the range of AV00 through AV99.
  1. COORDINATION
  1. In the FAA.
  1. The Mission Support Services Aeronautical Information Services (AIS) group is responsible for the coordination of requests for location identifiers within each service area.
  2. Any reapplication or change in usage of a location identifier assignment must receive prior clearance from AIS.
  3. Occasions will arise where a sponsor or interested group will seek the advice of regional/service area office or field personnel concerning the assignment of a particular identifier or a change to a more preferred identifier. Inquiries of this nature must be referred to AIS.
  1. The Department of Navy, Naval Telecommunications System, ICO-5, is responsible for final coordination and assignment of three letter identifiers beginning with the letter “N”.
  2. Transport Canada, Aeronautical Information Service, is responsible for final coordination and assignment of Canadian location identifiers.
  1. PERMANENCE
  1. Location identifiers are considered permanent and will not be changed without strong and documented justification, primarily concerning air safety or a significant change of landing facility status.
  2. Location identifiers are not interchangeable and cannot be transferred from one location to another or from one airport to another even within the same community.
  3. The original identifier will remain in effect, in most instances, even if it is necessary to change the facility's name.
  1. DUPLICATION
  1. When assigning location identifiers within the boundaries of an established landing area, a location identifier may be assigned more than once; however, the following restrictions apply. The same identifier may be assigned to:
  1. The landing area.
  2. One landing facility.
  3. Each unique navigational aid (NAVAID) type.
  4. One manned air traffic control facility.
  5. Each unique weather station.
  6. With certain restrictions, variations of the airport identifier may also be assigned to landing systems.
  1. Some duplication of three-letter assignments has been made between air navigation facilities in the contiguous United States, which are not associated primarily with a landing area, and U.S. Department of Defense overseas air bases. For example, the second ILS at an airport in the U.S. and an air base in Italy, or an air base in Germany and an en route VORTAC in the U.S.
  2. 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.
  1. EFFECTIVE DATES

Location identifiers are published in the next edition of the order, following assignment. All segments of the aviation industry and many related activities use these codes in their daily business. The effective date of the assignment, therefore, is set by each user group according to their respective requirements.

  1. ASSIGNMENT SYSTEM
  1. Three-letter identifiers are assigned as radio call signs to:
  1. Aeronautical navigation aids (NAVAIDS).
  2. Airports:
  1. with a manned air traffic control facility.
  2. with a navigational aid (NAVAID) within airport boundaries.
  3. that receive scheduled route air carriers.
  4. that receive military airlift services.
  5. designated by the U.S. Customs Service as Airports of Entry.
  1. Some staffed aviation weather reporting stations.
  2. Public use airports commissioning Automated Weather Observations Systems, level III (AWOS-III) or higher that have paved runways 5,000 feet or longer.
  3. Weather reporting systems approved for national dissemination of weather data.
  1. When located on a public use airport, the AWOS identifier will match the airport identifier. This may be a three-letter identifier or a three-character identifier.
  2. When located on a private use airport- the AWOS will be assigned a unique, three-letter or three-character identifier- unrelated to the airport identifier.
  3. When located off airport, the AWOS will be assigned a unique, three-letter or three-character identifier.
  1. Navigation aid identifiers are assigned by the following standards:
  1. Instrument Landing System (ILS), Localizer type Directional Aid (LDA), Simplified Directional Facility (SDF), and associated Distance Measuring Equipment (DME):
  1. The initial localizer commissioned at a landing facility-whether it is associated with an ILS, LDA, or SDF, is usually assigned the same identifier as the landing facility that it serves. This may be altered to a unique, three letter identifier if the airport has not yet been assigned a three letter identifier or if the assigned airport identifier begins with `K', `N' or `W'.
  2. If additional localizers are established at the same landing facility, whether it is associated with an ILS, LDA, or SDF, each localizer will be assigned a unique three letter identifier.
  3. If a DME is installed as an integral component of the ILS, the DME is assigned the same identifier as the associated ILS.
  4. The keyed ILS, LDA, or DME identifier is preceded by the letter “I" and a dash.

EXAMPLE-

The initial LOC at ORD is keyed I-ORD.

  1. The keyed SDF identifier is not preceded by a letter.
  1. Interim Standard Microwave Landing System (ISMLS):
  1. The initial ISMLS commissioned at a landing facility is usually assigned the same identifier as the landing facility that it serves. This may be altered to a unique three letter identifier if the airport has not yet been assigned a three letter identifier or if the assigned airport identifier begins with `K', `N' or `W'.
  2. If an LOC and ISMLS are installed on the same runway end, the ISMLS will be assigned the same identifier as the LOC.
  3. The LOC identifier will be preceded by the letter “I" and a dash. The ISMLS identifier will be preceded by the letter “M" and a dash.
  4. If additional ISMLS are established at the same landing facility, each ILMSL will be assigned a unique three letter identifier.
  1. Compass Locators. The general term “compass locator" also covers NDB/OM, LMM, and LOM regardless of output power or type. The term is applied only to a non-direction radio facility which is located at the VHF middle or outer marker site (front course) of an ILS. It is assigned a name-code and a two-letter identifier. The two-letter identifier is derived in the following manner:
  1. The three-letter localizer identifier is considered as a base.
  2. The first and second letters of the three-letter localizer identifier are assigned to the outer marker compass locator (LOM) and the second and third letters are assigned to the middle marker compass locator (LMM).

EXAMPLE-

Raleigh-Durham

ILS

Localizer

I-RDU

LOM

RD

LMM

DU

  1. Non-directional Radio beacon. Non-directional radio beacons are assigned three-letter identifiers except when they are also the outer compass locator (LOM) or middle compass locator (LMM) of an ILS, or placed at a marker site of an ILS. See Compass Locators above. The same basic three-letter identifier cannot be shared by a terminal NDB and an ILS at the same location.
  2. VOR, VORTAC, and TACAN Facilities. These facilities are assigned three-letter identifiers. If two or more such facilities or an NDB are established at a location, they will be assigned different identifiers. The same basic three-letter identifier can be assigned to one of these terminal facilities and to an ILS localizer at the same location.
  3. Distance Measuring Equipment (DME). This equipment is used in conjunction with several type navigation aids. It is assigned the same identifier as its associated aid, whether a VOR/DME, NDB/DME, or ILS/DME.
  4. Ground Based Augmentation System (GBAS) Facilities. These facilities are assigned the same three letter identifiers as the landing airport at which they are physically located. If multiple GBAS runway records are established at the airport or associated airports within its service volume, they will each be assigned the same GBAS facility identifier.
  1. 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.
  2. 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.
  2. Identifiers in this series, which could conflict with the “Victor”, “Jet” or colored airway numbers are not assigned.
  1. 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.
  1. The following supplemental codes are used in this identifier series:

AA

Alaska

AN

Arizona

AS

Arkansas

CL

California

CN

California

CD

Colorado

FA

Florida

FD

Florida

GE

Georgia

IS

Illinois

LL

Illinois

IG

Indiana

II

Indiana

SN

Kansas

KY

Kentucky

LS

Louisiana

MY

Minnesota

MU

Missouri

VE

Nevada

JY

New Jersey

NK

New York

NR

North Carolina

NA

North Dakota

OA

Ohio

OI

Ohio

OL

Oklahoma

OG

Oregon

PN

Pennsylvania

PS

Pennsylvania

TA

Texas

TE

Texas

TS

Texas

XA

Texas

XS

Texas

TT

Texas

VG

Virginia

WN

Wisconsin

WS

Wisconsin

WT

Washington

  1. A single five-letter pronounceable combination serves as the fix name, assigned identifier and computer code. If a new fix is to be collocated with an existing navigation aid, ILS marker, way point, or other type fix, the original name or name-code applies to both.
  2. Weather Offices and Stations, may be assigned in any of the series of Location Identifiers, depending upon type or combination of Station. Generally, a Weather Service Office at an Airport is given a three-letter identifier. AMOS equipment may be polled with any combination of three-character identifiers. Some types of Aviation Weather Reporting Stations are listed with two-number, one-letter identifiers.
  1. CANCELED ASSIGNMENTS
  1. All users are requested to periodically review assignments in their area of responsibility, and notify Aeronautical Information Services as soon as an identifier or name-code may be canceled.
  2. Canceled three-letter assignments are held in abeyance for one year, usually, before becoming available for reassignment.
  3. Canceled number-alpha and five-letter assignments are held in abeyance an appropriate length of time depending upon circumstances of cancellation, but not more than one year.
  1. CORRECTIONS
  1. Upon receipt of this order, users are requested to verify the proper listing of identifiers in their area of responsibility. Omitted, incorrect and obsolete assignments and tie-in facilities should be reported immediately to Aeronautical Information Services. If available, include the correct information. See Paragraph 1-1-4., for appropriate action dates.
  2. A page is included inside the front cover for this purpose.
  1. TIE-IN FACILITY

The “FAA TIE-IN FACILITY” is the telecommunications facility that handles flight plan messages for the listed landing facility or navigational aid. This also applies to Canadian facilities. Tie-in facility hours are local times. The absence of a facility in this column indicates that the location identifier is being reserved for the future commissioning of the landing facility or navigational aid.

  1. ARTCC CONTROL AREA

The computer code for the U.S. Air Route Traffic Control Center or identifier of the Canadian ARTCC (see note below) of jurisdiction is shown beside the tie-in facility identifier opposite each landing facility and navigational aid listing. This information has been included to assist in routing IFR Flight Planning messages directly to ARTCC computers. The absence of a facility in this column indicates that the location identifier is being reserved for the future commissioning of the landing facility or navigational aid.

NOTE-

These may change for any landing facility or navigational aid depending on letters of agreement, ARTCC boundary realignment, hours of service, traffic flight levels or altitudes. Additions, deletions or changes of such information must be provided to Aeronautical Information Services by the appropriate Air Traffic facility.

  1. METROPOLITAN AREA IDENTIFIERS

A number of three-letter identifiers have been assigned in the past to designate a metropolitan area where a principal city is served by more than one airport, however, no further assignment of metropolitan codes is contemplated. Existing metropolitan codes are not exchangeable with airport codes at the same location.

  1. RECORDS AND REVIEWS
  1. Location Identifiers System records are retained for five years. Research of assignments beyond that time may be done only from history copies of the order.
  2. Continuing reviews are conducted to update assignments in the Location Identifiers System. Assignments of more than five years are subject to over all reviews and meeting current standards.
  1. RESERVED IDENTIFIERS

A number of identifiers have been reserved for the future commissioning of navigational aids and airports. These locations and identifiers will be listed without an associated tie-in facility or center code.