designated via NOTAM as either a TFR or stationary  ALTRV. Unless otherwise specified, the vertical  limits of an AHA are from the surface to unlimited.  (See CONTINGENCY HAZARD AREA.)  (See REFINED HAZARD AREA.)  (See TRANSITIONAL HAZARD AREA.)  the desired interval between successive arrival  aircraft.  AIRPORT DEPARTURE RATE (ADR)- A dynamic  parameter specifying the number of aircraft which  can depart an airport and the airspace can accept per  hour.  AIRPORT ELEVATION- The highest point of an  airport's usable runways measured in feet from mean  sea level.  (See TOUCHDOWN ZONE ELEVATION.)  (See ICAO term AERODROME ELEVATION.)  AIRPORT LIGHTING- Various lighting aids that  may be installed on an airport. Types of airport  lighting include:  a.  Approach Light System (ALS)- An airport  lighting facility which provides visual guidance to  landing aircraft by radiating light beams in a  directional pattern by which the pilot aligns the  aircraft with the extended centerline of the runway on  his/her final approach for landing. Condenser- Discharge Sequential Flashing Lights/Sequenced  Flashing Lights may be installed in conjunction with  the ALS at some airports. Types of Approach Light  Systems are:  1.  ALSF-1- Approach Light System with  Sequenced Flashing Lights in ILS Cat-I configura- tion.  2.  ALSF-2- Approach Light System with  Sequenced Flashing Lights in ILS Cat-II configura- tion. The ALSF-2 may operate as an SSALR when  weather conditions permit.  3.  SSALF- Simplified Short Approach Light  System with Sequenced Flashing Lights.  4.  SSALR- Simplified Short Approach Light  System with Runway Alignment Indicator Lights.  5.  MALSF- Medium Intensity Approach Light  System with Sequenced Flashing Lights.  6.  MALSR- Medium Intensity Approach Light  System with Runway Alignment Indicator Lights.  7.  RLLS- Runway Lead-in Light System  Consists of one or more series of flashing lights  installed at or near ground level that provides positive  visual guidance along an approach path, either  curving or straight, where special problems exist with  hazardous terrain, obstructions, or noise abatement  procedures.  8.  RAIL- Runway Alignment Indicator Lights- Sequenced Flashing Lights which are installed only  in combination with other light systems.  AIRPORT ARRIVAL RATE (AAR)- A dynamic  input parameter specifying the number of arriving  aircraft which an airport or airspace can accept from  the ARTCC per hour. The AAR is used to calculate  AIRPORT ADVISORY AREA- The area within ten  miles of an airport without a control tower or where  the tower is not in operation, and on which a Flight  Service Station is located.  (See LOCAL AIRPORT ADVISORY.)  (Refer to AIM.)  AIRPORT- An area on 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.  (See AWW.)  (See CONVECTIVE SIGMET.)  (See CWA.)  (See SIGMET.)  (Refer to AIM.)  AIRMEN'S METEOROLOGICAL INFORMA- TION (AIRMET)- In-flight weather advisories  issued only to amend the Aviation Surface Forecast,  Aviation Cloud Forecast, or area forecast concerning  weather phenomena which are of operational interest  to all aircraft and potentially hazardous to aircraft  having limited capability because of lack of  equipment, instrumentation, or pilot qualifications.  AIRMETs concern weather of less severity than that  covered by SIGMETs or Convective SIGMETs.  AIRMETs cover moderate icing, moderate turbu- lence, sustained winds of 30 knots or more at the  surface, widespread areas of ceilings less than 1,000  feet and/or visibility less than 3 miles, and extensive  mountain obscurement.  AIRCRAFT WAKE TURBULENCE CATE- GORIES- For the purpose of Wake Turbulence  Recategorization (RECAT) Separation Minima, ATC  groups aircraft into categories ranging from Category  A through Category I, dependent upon the version of  RECAT that is applied. Specific category assign- ments vary and are listed in the RECAT Orders.  Pilot/Controller Glossary Pilot/Controller Glossary  8/15/19 1/30/20  PCG A-7 