8/15/19 12/31/20  Pilot/Controller Glossary Pilot/Controller Glossary  e.  Weather and chaff information.  f.  Weather assistance.  g.  Bird activity information.  h.  Holding pattern surveillance. Additional ser- vices are provided to the extent possible contingent  only upon the controller's capability to fit them into  the performance of higher priority duties and on the  basis of limitations of the radar, volume of traffic,  frequency congestion, and controller workload. The  controller has complete discretion for determining if  he/she is able to provide or continue to provide a  service in a particular case. The controller's reason  not to provide or continue to provide a service in a  particular case is not subject to question by the pilot  and need not be made known to him/her.  (See TRAFFIC ADVISORIES.)  (Refer to AIM.)  ADF- ADIZ- ADLY- (See AUTOMATIC DIRECTION FINDER.)  (See AIR DEFENSE IDENTIFICATION ZONE.)  (See ARRIVAL DELAY.)  ADMINISTRATOR- The Federal Aviation Admin- istrator or any person to whom he/she has delegated  his/her authority in the matter concerned.  (See AIRPORT DEPARTURE RATE.)  (See ICAO term AUTOMATIC DEPENDENT  SURVEILLANCE.)  (See AUTOMATIC DEPENDENT  SURVEILLANCE-BROADCAST.)  (See AUTOMATIC DEPENDENT  SURVEILLANCE-CONTRACT.)  ADS-C- ADS-B- ADS [ICAO]- ADR- ADVISE INTENTIONS- Tell me what you plan to  do.  ADVISORY- Advice and information provided to  assist pilots in the safe conduct of flight and aircraft  movement.  (See ADVISORY SERVICE.)  ADVISORY FREQUENCY- The appropriate fre- quency to be used for Airport Advisory Service.  (See LOCAL AIRPORT ADVISORY.)  (See UNICOM.)  (Refer to ADVISORY CIRCULAR NO. 90-66.)  (Refer to AIM.)  ADVISORY SERVICE- Advice and information  provided by a facility to assist pilots in the safe  conduct of flight and aircraft movement.  (See ADDITIONAL SERVICES.)  (See LOCAL AIRPORT ADVISORY.)  (See RADAR ADVISORY.)  (See SAFETY ALERT.)  (See TRAFFIC ADVISORIES.)  (Refer to AIM.)  AERIAL REFUELING- A procedure used by the  military to transfer fuel from one aircraft to another  during flight.  (Refer to VFR/IFR Wall Planning Charts.)  AERODROME- A defined area on land or water  (including any buildings, installations and equip- ment) intended to be used either wholly or in part for  the arrival, departure, and movement of aircraft.  AERODROME BEACON [ICAO]- Aeronautical  beacon used to indicate the location of an aerodrome  from the air.  AERODROME CONTROL SERVICE [ICAO]- Air  traffic control service for aerodrome traffic.  AERODROME CONTROL TOWER [ICAO]- A  unit established to provide air traffic control service  to aerodrome traffic.  AERODROME ELEVATION [ICAO]- The eleva- tion of the highest point of the landing area.  AERODROME TRAFFIC CIRCUIT [ICAO]- The  specified path to be flown by aircraft operating in the  vicinity of an aerodrome.  AERONAUTICAL BEACON- A visual NAVAID  displaying flashes of white and/or colored light to  indicate the location of an airport, a heliport, a  landmark, a certain point of a Federal airway in  mountainous terrain, or an obstruction.  (See AIRPORT ROTATING BEACON.)  (Refer to AIM.)  AERONAUTICAL CHART- A map used in air  navigation containing all or part of the following:  topographic features, hazards and obstructions,  PCG A-2 