8/15/19 12/31/20  Pilot/Controller Glossary Pilot/Controller Glossary  AUTOMATIC DEPENDENT SURVEILLANCE- CONTRACT (ADS-C)- A data link position  reporting system, controlled by a ground station, that  establishes contracts with an aircraft's avionics that  occur automatically whenever specific events occur,  or specific time intervals are reached.  AUTOMATIC DEPENDENT SURVEILLANCE- REBROADCAST (ADS-R)- A datalink translation  function of the ADS-B ground system required to  accommodate the two separate operating frequencies  (978 MHz and 1090 MHz). The ADS-B system  receives the ADS-B messages transmitted on one  frequency and ADS-R translates and reformats the  information for rebroadcast and use on the other  frequency. This allows ADS-B In equipped aircraft  to see nearby ADS-B Out traffic regardless of the  operating link of the other aircraft. Aircraft operating  on the same ADS-B frequency exchange information  directly and do not require the ADS-R translation  function.  AUTOMATIC DIRECTION FINDER- An aircraft  radio navigation system which senses and indicates  the direction to a L/MF nondirectional radio beacon  (NDB) ground transmitter. Direction is indicated to  the pilot as a magnetic bearing or as a relative bearing  to the longitudinal axis of the aircraft depending on  the type of indicator installed in the aircraft. In certain  applications, such as military, ADF operations may  be based on airborne and ground transmitters in the  VHF/UHF frequency spectrum.  AUTOMATIC FLIGHT INFORMATION SER- VICE (AFIS) - ALASKA FSSs ONLY- The  continuous broadcast of recorded non-control  information at airports in Alaska where a FSS  provides local airport advisory service. The AFIS  broadcast automates the repetitive transmission of  essential but routine information such as weather,  wind, altimeter, favored runway, braking action,  airport NOTAMs, and other applicable information.  The information is continuously broadcast over a  discrete VHF radio frequency (usually the ASOS/  AWOS frequency).  AVIATION WEATHER SERVICE- A service  provided by the National Weather Service (NWS) and  FAA which collects and disseminates pertinent  weather information for pilots, aircraft operators, and  ATC. Available aviation weather reports and  forecasts are displayed at each NWS office and FAA  FSS.  AVAILABLE LANDING DISTANCE (ALD)- The  portion of a runway available for landing and roll-out  for aircraft cleared for LAHSO. This distance is  measured from the landing threshold to the  hold-short point.  c.  180 degrees Autorotation. Initiated from a  downwind heading and is commenced well inside the  normal traffic pattern. “Go around” may not be  possible during the latter part of this maneuver.  b.  Low Level Autorotation. Commences at an  altitude well below the traffic pattern, usually below  100 feet AGL and is used primarily for tactical  military training.  a.  Autorotative Landing/Touchdown Autorota- tion. Used by a pilot to indicate that the landing will  be made without applying power to the rotor.  AUTOROTATION- A rotorcraft flight condition in  which the lifting rotor is driven entirely by action of  the air when the rotorcraft is in motion.  AUTOMATIC TERMINAL INFORMATION SER- VICE [ICAO]- The provision of current, routine  information to arriving and departing aircraft by  means of continuous and repetitive broadcasts  throughout the day or a specified portion of the day.  relieve frequency congestion by automating the  repetitive transmission of essential but routine  information; e.g., “Los Angeles information Alfa.  One three zero zero Coordinated Universal Time.  Weather, measured ceiling two thousand overcast,  visibility three, haze, smoke, temperature seven one,  dew point five seven, wind two five zero at five,  altimeter two niner niner six. I-L-S Runway Two Five  Left approach in use, Runway Two Five Right closed,  advise you have Alfa.”  (See ICAO term AUTOMATIC TERMINAL  INFORMATION SERVICE.)  (Refer to AIM.)  (See BEARING.)  (See NONDIRECTIONAL BEACON.)  AUTOMATIC TERMINAL INFORMATION SER- VICE- The continuous broadcast of recorded  noncontrol information in selected terminal areas. Its  purpose is to improve controller effectiveness and to  (See TRANSCRIBED WEATHER BROADCAST.)  (See WEATHER ADVISORY.)  (Refer to AIM.)  PCG A-16 