Instrument Navigation

Navigation reference system (NRS) waypoints are RNAV waypoints which form a grid and are identified through the intersection of lines of latitude and longitude.  Currently totaling around 1,600 waypoints, they are deployed in all 20 ARTCCs throughout the continental United States; current density is one waypoint spaced every 30 minutes of latitude and every 2o of longitude.  The NRS waypoint names in current use consist of two letters followed by two numbers and a final letter (ex. KD54U).  The first letter “K” is the ICAO FIR for the United States.  The second letter (“D”) represents the ARTCC airspace in which the waypoint is located.  The two numbers (“54”) and the final letter (“U”) denote the lines of latitude and longitude, respectively, whose intersection define the waypoint. A number of human factors issues for both pilots and air traffic controllers were identified relative to NRS waypoint nomenclature and general usability prior to their deployment in the NAS in 2005-2006 but it was hoped that these would dissipate over time with greater operator familiarity and use.  We have been asked to examine NRS waypoint human factors issues that still exist, if any, now that they have been in use in the NAS for approximately 5 years and to develop recommended solutions and mitigations for any issues discovered.

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