Sec.  87.5   Definitions.

   Aeronautical advisory station (unicom). An aeronautical station used for
   advisory and civil defense communications primarily with private aircraft
   stations.

   Aeronautical enroute station. An aeronautical station which communicates
   with aircraft stations in flight status or with other aeronautical enroute
   stations.

   Aeronautical fixed service. A radiocommunication service between specified
   fixed points provided primarily for the safety of air navigation and for the
   regular, efficient and economical operation of air transport. A station in
   this service is an aeronautical fixed station.

   Aeronautical Mobile Off-Route (OR) Service. An aeronautical mobile service
   intended  for  communications,  including  those  relating  to  flight
   coordination,  primarily  outside  national or international civil air
   routes.(RR)

   Aeronautical  Mobile Route (R) Service. An aeronautical mobile service
   reserved for communications relating to safety and regularity of flight,
   primarily along national or international civil air routes.(RR)

   Aeronautical  Mobile-Satellite Off-Route (OR) Service. An aeronautical
   mobile-satellite  service intended for communications, including those
   relating  to  flight  coordination,  primarily  outside  national  and
   international civil air routes.(RR)

   Aeronautical  Mobile-Satellite  Route  (R)  Service.  An  aeronautical
   mobile-satellite service reserved for communications relating to safety and
   regularity of flights, primarily along national or international civil air
   routes.(RR)

   Aeronautical Mobile-Satellite Service. A mobile-satellite service in which
   mobile earth stations are located on board aircraft.

   Aeronautical mobile service. A mobile service between aeronautical stations
   and aircraft stations, or between aircraft stations, in which survival craft
   stations may also participate; emergency position-indicating radiobeacon
   stations may also participate in this service on designated distress and
   emergency frequencies.

   Aeronautical multicom station. An aeronautical station used to provide
   communications to conduct the activities being performed by, or directed
   from, private aircraft.

   Aeronautical radionavigation service. A radionavigation service intended for
   the benefit and for the safe operation of aircraft.

   Aeronautical  search  and  rescue station. An aeronautical station for
   communication  with  aircraft and other aeronautical search and rescue
   stations pertaining to search and rescue activities with aircraft.

   Aeronautical station. A land station in the aeronautical mobile service. In
   certain instances an aeronautical station may be located, for example, on
   board ship or on a platform at sea.

   Aeronautical utility mobile station. A mobile station used on airports for
   communications relating to vehicular ground traffic.

   Air carrier aircraft station. A mobile station on board an aircraft which is
   engaged in, or essential to, the transportation of passengers or cargo for
   hire.

   Aircraft earth station (AES). A mobile earth station in the aeronautical
   mobile-satellite service located on board an aircraft.

   Aircraft station. A mobile station in the aeronautical mobile service other
   than a survival craft station, located on board an aircraft.

   Airport. An area of land or water that is used or intended to be used for
   the  landing  and  takeoff of aircraft, and includes its buildings and
   facilities, if any.

   Airport control tower (control tower) station. An aeronautical station
   providing communication between a control tower and aircraft.

   Automatic  dependent surveillance—broadcast (ADS–B) Service. Broadcast
   transmissions   from   aircraft,  supporting  aircraft-to-aircraft  or
   aircraft-to-ground surveillance applications, including position reports,
   velocity vector, intent and other relevant information about the aircraft.

   Automatic terminal information service-broadcast (ATIS-B). The automatic
   provision of current, routine information to arriving and departing aircraft
   throughout a 24-hour period or a specified portion thereof.

   Automatic  weather  observation  station  (AWOS)  or automatic surface
   observation station (ASOS). A land station located at an airport and used to
   automatically transmit weather information to aircraft.

   Aviation service organization. Any business firm which maintains facilities
   at an airport for the purposes of one or more of the following general
   aviation activities: (a) Aircraft fueling; (b) aircraft services (e.g.
   parking,  storage,  tie-downs); (c) aircraft maintenance or sales; (d)
   electronics equipment maintenance or sales; (e) aircraft rental, air taxi
   service or flight instructions; and (f) baggage and cargo handling, and
   other passenger or freight services.

   Aviation  services.  Radio-communication services for the operation of
   aircraft. These services include aeronautical fixed service, aeronautical
   mobile service, aeronautical radiodetermination service, and secondarily,
   the handling of public correspondence on frequencies in the maritime mobile
   and maritime mobile satellite services to and from aircraft.

   Aviation  support  station. An aeronautical station used to coordinate
   aviation services with aircraft and to communicate with aircraft engaged in
   unique or specialized activities. (See subpart K)

   Differential GPS (DGPS). A system which transmits corrections to the GPS
   derived position.

   Emergency locator transmitter (ELT). A transmitter of an aircraft or a
   survival  craft  actuated manually or automatically that is used as an
   alerting and locating aid for survival purposes.

   Emergency locator transmitter (ELT) test station. A land station used for
   testing ELTs or for training in the use of ELTs.

   Expendable Launch Vehicle (ELV). A booster rocket that can be used only once
   to launch a payload, such as a missile or space vehicle.

   Flight Information Service-Broadcast (FIS-B). A broadcast service provided
   for the purpose of giving advice and information useful for the safe and
   efficient conduct of flights.

   Flight test aircraft station. An aircraft station used in the testing of
   aircraft or their major components.

   Flight test land station. An aeronautical station used in the testing of
   aircraft or their major components.

   Glide path station. A radionavigation land station which provides vertical
   guidance to aircraft during approach to landing.

   Instrument landing system (ILS). A radionavigation system which provides
   aircraft  with horizontal and vertical guidance just before and during
   landing  and,  at  certain fixed points, indicates the distance to the
   reference point of landing.

   Instrument landing system glide path. A system of vertical guidance embodied
   in the instrument landing system which indicates the vertical deviation of
   the aircraft from its optimum path of descent.

   Instrument  landing  system localizer. A system of horizontal guidance
   embodied in the instrument landing system which indicates the horizontal
   deviation of the aircraft from its optimum path of descent along the axis of
   the runway or along some other path when used as an offset.

   Land station. A station in the mobile service not intended to be used while
   in motion.

   Localizer station. A radionavigation land station which provides horizontal
   guidance to aircraft with respect to a runway center line.

   Marker beacon station. A radionavigation land station in the aeronautical
   radionavigation service which employs a marker beacon. A marker beacon is a
   transmitter which radiates vertically a distinctive pattern for providing
   position information to aircraft.

   Mean power (of a radio transmitter). The average power supplied to the
   antenna  transmission line by a transmitter during an interval of time
   sufficiently long compared with the lowest frequency encountered in the
   modulation taken under normal operating conditions.

   Microwave landing system. An instrument landing system operating in the
   microwave spectrum that provides lateral and vertical guidance to aircraft
   having compatible avionics equipment.

   Mobile  service.  A radiocommunication service between mobile and land
   stations, or between mobile stations. A mobile station is intended to be
   used while in motion or during halts at unspecified points.

   Operational  fixed  station.  A  fixed  station,  not  open  to public
   correspondence, operated by and for the sole use of persons operating their
   own radiocommunication facilities in the public safety, industrial, land
   transportation, marine, or aviation services.

   Peak envelope power (of a radio transmitter). The average power supplied to
   the antenna transmission line by a transmitter during one radio frequency
   cycle at the crest of the modulation envelope taken under normal operating
   conditions.

   Private aircraft station. A mobile station on board an aircraft not operated
   as an air carrier. A station on board an air carrier aircraft weighing less
   than 12,500 pounds maximum certified takeoff gross weight may be licensed as
   a private aircraft station.

   Racon station. A radionavigation land station which employs a racon. A racon
   (radar  beacon)  is  a  transmitter-receiver  associated  with a fixed
   navigational mark, which when triggered by a radar, automatically returns a
   distinctive signal which can appear on the display of the triggering radar,
   providing range, bearing and identification information.

   Radar. A radiodetermination system based upon the comparison of reference
   signals with radio signals reflected, or re-transmitted, from the position
   to be determined.

   Radio  altimeter.  Radionavigation  equipment, on board an aircraft or
   spacecraft, used to determine the height of the aircraft or spacecraft above
   the Earth's surface or another surface.

   Radiobeacon station. A station in the radionavigation service the emissions
   of which are intended to enable a mobile station to determine its bearing or
   direction in relation to the radiobeacon station.

   Radiodetermination  service.  A  radiocommuncation  service which uses
   radiodetermination. Radiodetermination is the determination of the position,
   velocity and/or other characteristics of an object, or the obtaining of
   information relating to these parameters, by means of the propagation of
   radio  waves. A station in this service is called a radiodetermination
   station.

   Radiolocation service. A radiodetermination service for the purpose of
   radiolocation. Radiolocation is the use of radiodetermination for purposes
   other than those of radionavigation.

   Radionavigation land test stations. A radionavigation land station which is
   used to transmit information essential to the testing and calibration of
   aircraft  navigational aids, receiving equipment, and interrogators at
   predetermined surface locations. The Maintenance Test Facility (MTF) is used
   primarily to permit maintenance testing by aircraft radio service personnel.
   The Operational Test Facility (OTF) is used primarily to permit the pilot to
   check a radionavigation system aboard the aircraft prior to takeoff.

   Radionavigation service. A radiodetermination service for the purpose of
   radionavigation. Radionavigation is the use of radiodetermination for the
   purpose of navigation, including obstruction warning.

   Re-usable launch vehicle (RLV). A booster rocket that can be recovered after
   launch, refurbished and re-launched.

   Surveillance  radar  station.  A  radionavigation  land station in the
   aeronautical radionavigation service employing radar to display the presence
   of aircraft within its range.

   Survival craft station. A mobile station in the maritime or aeronautical
   mobile service intended solely for survival purposes and located on any
   lifeboat, life raft or other survival equipment.

   Traffic  information  services—broadcast  (TIS–B). Traffic information
   broadcasts derived from ground-based radar systems.

   Universal access transceiver (UAT). A radio datalink system authorized to
   operate  on  the  frequency  978  MHz  to  support Automatic Dependent
   Surveillance—Broadcast    (ADS–B)    Service,    Traffic   Information
   Services—Broadcast (TIS–B) and Flight Information Service—Broadcast (FIS–B).

   VHF Omni directional range station (VOR). A radionavigation land station in
   the aeronautical radionavigation service providing direct indication of the
   bearing (omni-bearing) of that station from an aircraft.

   [ 53 FR 28940 , Aug. 1, 1988, as amended at  54 FR 11719 , Mar. 22, 1989;  54 FR 49995 , Dec. 4, 1989;  55 FR 4175 , Feb. 7, 1990;  57 FR 45749 , Oct. 5, 1992;  64 FR 27474 , May 20, 1999;  69 FR 32879 , June 14, 2004;  71 FR 70676 , Dec. 6,
   2006]

Subpart B—Applications and Licenses