ENR 4.4: Name-Code Designators for Significant Points

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

2.1 In addition to pronounceable five-letter name codes, the FAA uses alphanumeric designators for high en route waypoints as follows:

2.2 Gulf of America Grid System, described in ENR 6.1.

2.3 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.”

2.3.1 The second character is an NRS letter code that denotes the High Air Route Traffic Control Center (ARTCC), per TBL ENR 4.4-1:

2.3.2 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:

2.3.3 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:

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