Originally published in 1994
The Federal Aviation Administration and the Department of Defense have reached agreement to permit Global Positioning System (GPS) satellite use for civil air navigation. Aircraft currently may use GPS for enroute and terminal flight operations as well as non precision instrument approaches at approved locations.
By year’s end, 3900 GPS approaches are scheduled to be authorized which “overlay” NDB or VOR approaches. Using a TSO C129 receiver, a pilot may execute the GPS approach without monitoring any other NAVAID. Denton Municipal was one of only three in the nation to receive the first “stand alone” non precision GPS approach this summer. These are GPS approaches which do not overlay a previous non precision approach. Texas has twelve more airports programmed to receive “stand alone” approaches in the next year.
Precision GPS approaches, where glide slope guidance is provided, must wait for Wide Area Augmentation System (WAAS) development and installation. The FAA is investigating systems of either ground or satellite receiver/transmitters which correct GPS signals to Instrument Landing System (ILS) standards. GPS precision approaches with WAAS correction factors will mimic ILS approaches, but will be available at airports currently not served by a precision approach as well as at those which are. The FAA has set an aggressive timetable for WAAS, targeting 1997 for initial operating capability.