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12/2/21 

Pilot/Controller Glossary 

b. 

ASLAR procedures shall be covered in a Letter 

of Agreement between the responsible USAF 
military ATC facility and the concerned Federal 
Aviation Administration facility. Initial Approach 
Fix spacing requirements are normally addressed as 
a minimum. 

AIRCRAFT HAZARD AREA (AHA)

 Used by 

ATC to segregate air traffic from a launch vehicle, 
reentry vehicle, amateur rocket, jettisoned stages, 
hardware, or falling debris generated by failures 
associated with any of these activities. An AHA is 
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.) 

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. 

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. 

(See CONVECTIVE SIGMET.) 
(See CWA.) 
(See SAW.) 
(See SIGMET.) 
(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. 

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 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 
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. 

PCG A