Pilot/Controller Glossary AIRPORT RESERVATION OFFICE- Office responsible for monitoring the operation of slot controlled airports. It receives and processes requests for unscheduled operations at slot controlled airports. AIRPORT ROTATING BEACON- A visual NAVAID operated at many airports. At civil airports, alternating white and green flashes indicate the location of the airport. At military airports, the beacons flash alternately white and green, but are differentiated from civil beacons by dualpeaked (two quick) white flashes between the green flashes. (See INSTRUMENT FLIGHT RULES.) (See SPECIAL VFR OPERATIONS.) (See ICAO term AERODROME BEACON.) (Refer to AIM.) AIRPORT SURFACE DETECTION EQUIPMENT (ASDE)- Surveillance equipment specifically designed to detect aircraft, vehicular traffic, and other objects, on the surface of an airport, and to present the image on a tower display. Used to augment visual observation by tower personnel of aircraft and/or vehicular movements on runways and taxiways. There are three ASDE systems deployed in the NAS: a. ASDE-3- a Surface Movement Radar. b. ASDE-X- a system that uses an X-band Surface Movement Radar, multilateration, and ADS-B. c. Airport Surface Surveillance Capability (ASSC)- A system that uses Surface Movement Radar, multilateration, and ADS-B. AIRPORT SURVEILLANCE RADAR- Approach control radar used to detect and display an aircraft"s position in the terminal area. ASR provides range and azimuth information but does not provide elevation data. Coverage of the ASR can extend up to 60 miles. AIRPORT TAXI CHARTS- (See AERONAUTICAL CHART.) AIRPORT TRAFFIC CONTROL SERVICE- A service provided by a control tower for aircraft operating on the movement arend in the vicinity of an airport. (See MOVEMENT AREA.) (See TOWER.) (See ICAO term AERODROME CONTROL SERVICE.) AIRPORT TRAFFIC CONTROL TOWER- (See TOWER.) AIRSPACE CONFLICT- Predicted conflict of an aircraft and active Special Activity Airspace (SAA). AIRSPACE FLOW PROGRAM (AFP)- AFP is a Traffic Management (TM) process administered by the Air Traffic Control System Command Center (ATCSCC) where aircraft are assigned an Expect Departure Clearance Time (EDCT) in order to manage capacity and demand for a specific area of the National Airspace System (NAS). The purpose of the program is to mitigate the effects of en route constraints. It is a flexible program and may be implemented in various forms depending upon the needs of the air traffic system. AIRSPACE HIERARCHY- Within the airspace classes, there is a hierarchy and, in the event of an overlap of airspace: Class A preempts Class B, Class B preempts Class C, Class C preempts Class D, Class D preempts Class E, and Class E preempts Class G. AIRSPEED- The speed of an aircraft relative to its surrounding air mass. The unqualified term "airspeed" means one of the following: a. Indicated Airspeed- The speed shown on the aircraft airspeed indicator. This is the speed used in pilot/controller communications under the general term "airspeed." (Refer to 14 CFR Part 1.) b. True Airspeed- The airspeed of an aircraft relative to undisturbed air. Used primarily in flight planning and en route portion of flight. When used in pilot/controller communications, it is referred to as "true airspeed" and not shortened to "airspeed."