25 May 2005
Require the Contractor to assist in Government flight checks of
NAVAIDS before acceptance and operation.
Electronic NAVAID Components
En Route Navigation Equipment. Paragraphs 3-126.96.36.199 through 3-
188.8.131.52 are brief descriptions of the most common en route electronic navigation
or Very High Frequency Omnidirectional Range,
primary navigation facility for en route aircraft navigation. The VOR system in the United
States consists of a series of ground stations that broadcast directional signals that are
used by aircraft to determine bearings to or from the broadcasting stations.
Terminal VOR (TVOR). A TVOR is a VOR located on an airfield that
provides terminal guidance for aircraft.
Distance Measuring Equipment (DME). DME transmits a signal that tells
the distance an aircraft is from the DME location.
Tactical Air Navigation (TACAN). A TACAN is an en route navigation aid
developed by the military that provides both directional and distance information.
VORTAC. A VORTAC is a collocated VOR and TACAN.
Non-directional Beacon (NDB). A non-directional beacon provides
guidance to and from the NDB antenna location.
Runway Approach NAVAIDS. There are two electronic NAVAIDS that
can be used for guidance to aircraft during IMC runway approaches.
Instrument Landing System (ILS). An ILS is a system that transmits
guidance information to equipment in the approaching aircraft. The ILS consists of three
Localizer. Equipment that indicates if the aircraft is right or left or on
the correct lateral alignment for a runway landing.
Glide Slope. Equipment that indicates the correct angle of descent to
Markers. The outer and middle marker signals an aircraft when it
crosses over the marker location indicating a certain distance from the
runway. An inner marker is also required for Category II landings. A
DME can be used in lieu of markers if it is located with the localizer.
Precision Approach Radar (PAR). PAR is an electronic NAVAID that is
not dependent on airborne navigation equipment. The PAR provides the air traffic