ENR 4.4 Name-Code Designators for Significant Points

1.. Data Set

1. The FAA provides aeronautical data via the following website: https://www.faa.gov/air_traffic/flight_info/­aeronav/aero_data/.

2.. Alphanumeric Waypoints

1. In addition to pronounceable five-letter name codes, the FAA uses alphanumeric designators for high en ­route waypoints as follows:
2. Gulf of America Grid System, described in ENR 6.1.
3. National Reference System (NRS). The NRS is a grid of waypoints in the 48 contiguous United States and ­neighboring offshore airspace where the FAA provides air traffic services. These waypoints are published on the ­U.S. Government Flight Information Publication, IFR Enroute High Altitude – U.S. Charts. Waypoints are ­currently spaced every 30 minutes of latitude and every 2 degrees of longitude, and are assigned alphanumeric ­designators that begin with the letter “K.”
   1. The second character is an NRS letter code that denotes the High Air Route Traffic Control Center ­(ARTCC), per TBL ENR 4.4-1:

      TBL ENR 4.4-1National Reference System (NRS) High ARTCC Code Listing

      High ARTCC	Location ­Identifier	NRS ­ARTCC ­Code
      Albuquerque	ZAB	A
      Atlanta	ZTL	T
      Boston	ZBW	B
      Chicago	ZAU	G
      Cleveland	ZOB	C
      Denver	ZDV	D
      Fort Worth	ZFW	F
      Houston	ZHU	H
      Indianapolis	ZID	I
      Jacksonville	ZJX	J
      Kansas City	ZKC	K
      Los Angeles	ZLA	L
      Memphis	ZME	M
      Miami	ZMA	R
      Minneapolis	ZMP	P
      New York	ZNY	N
      Oakland	ZOA	O
      Salt Lake City	ZLC	U
      Seattle	ZSE	S
      Washington	ZDC	W

   2. The third and fourth characters are numbers that denote the latitude. The latitude increment numbers start ­at the equator, which is designated “00.” Each 10-minute increment is then identified by a number between “01” ­and “90.” The latitude numbering sequence repeats each 15 degrees of latitude. TBL ENR 4.4-2 shows the third ­and fourth characters used by the FAA:

      TBL ENR 4.4-2National Reference System (NRS) Third and Fourth Characters (Latitude) Used by the FAA

      3rd and 4th ­Characters	Latitude
      57	N 24° 30'
      60	N 25° 00'
      63	N 25° 30'
      66	N 26° 00'
      69	N 26° 30'
      72	N 27° 00'
      75	N 27° 30'
      78	N 28° 00'
      81	N 28° 30'
      84	N 29° 00'
      87	N 29° 30'
      00	N 30° 00'
      03	N 30° 30'
      06	N 31° 00'
      09	N 31° 30'
      12	N 32° 00'
      15	N 32° 30'
      18	N 33° 00'
      21	N 33° 30'
      24	N 34° 00'
      27	N 34° 30'
      30	N 35° 00'
      33	N 35° 30'
      36	N 36° 00'
      39	N 36° 30'
      42	N 37° 00'
      45	N 37° 30'
      48	N 38° 00'
      51	N 38° 30'
      54	N 39° 00'
      57	N 39° 30'
      60	N 40° 00'
      63	N 40° 30'
      66	N 41° 00'
      69	N 41° 30'
      70	N 41° 40'
      72	N 42° 00'
      75	N 42° 30'
      78	N 43° 00'
      81	N 43° 30'
      84	N 44° 00'
      87	N 44° 30'
      00	N 45° 00'
      03	N 45° 30'
      06	N 46° 00'
      09	N 46° 30'
      12	N 47° 00'
      15	N 47° 30'
      18	N 48° 00'
      21	N 48° 30'

   3. The last character is a letter that denotes the longitude. The longitude letters start at the Greenwich ­meridian and go from west to east around the globe, repeating every 26 degrees. TBL ENR 4.4-3 shows the ­longitude letters used by the FAA:

      TBL ENR 4.4-3National Reference System (NRS) Longitude Letters Used by FAA

      Letter	Longitude
      Y	W 128°
      A	W 126°
      C	W 124°
      E	W 122°
      G	W 120°
      I	W 118°
      K	W 116°
      M	W 114°
      O	W 112°
      Q	W 110°
      S	W 108°
      U	W 106°
      W	W 104°
      Y	W 102°
      A	W 100°
      C	W 98°
      E	W 96°
      G	W 94°
      I	W 92°
      K	W 90°
      M	W 88°
      O	W 86°
      Q	W 84°
      S	W 82°
      U	W 80°
      W	W 78°
      Y	W 76°
      A	W 74°
      C	W 72°
      E	W 70°
      G	W 68°
      I	W 66°

   4. Figure ENR 4.4-1 provides a graphical depiction of NRS naming: