§  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