Aeronautical Information Circular — Page 15, Lesson 22

I want to walk you through the beginning of the Definitions section of the Aeronautical Information Circular, which is essentially the glossary for the entire communications and navigation syllabus. This is the professional vocabulary you will use every day as a pilot, so we need to get each term exactly right. Let's start with the main document types. AIM stands for ATFM Information Message — that's a message related to Air Traffic Flow Management. AIP is the Aeronautical Information Publication, the primary document containing long-term aeronautical information. AIRAC is Aeronautical Information Regulation and Control, which is the system that governs when certain aeronautical information changes take effect. AIREP is an Air Report — a report made from an aircraft in flight. AIS is Aeronautical Information Services, the overall service that provides the information pilots and operators need. Now for aerodrome and ground terms. ALA is an Alighting Area — that's any area where an aircraft can land, not necessarily a full aerodrome. ACH is Asymmetric Committed Height, a performance term for engine-out situations. ACK means Acknowledge. ALERF is the Alert Phase — one of the emergency phases. ACL is Altimeter Check Location, a specific point where you verify your altimeter setting. ACN is Aircraft Classification Number, which tells you the pavement-strength rating of an aircraft. ACP is Acceptance as a message type designator. ACPT means Accept or Accepted. ACT means Active, Activated, or Activity. Moving on. AD is simply Aerodrome. ADA is Advisory Area — an area where an advisory service is provided. ADDN means Addition or Additional. ADF is Automatic Direction Finding Equipment, the classic radio navigation aid that points to a beacon. ADGE is Air Defence Ground Environment. ADIZ — pronounced 'AY-DIZ' — is Air Defence Identification Code, not to be confused with the Air Defence Identification Zone you may have heard of; here it's specifically the code. ADJ means Adjacent. ADR is Advisory Route. ADS is Automatic Dependent Surveillance, and ADSU is the Automatic Dependent Surveillance Unit. ADT is Approved Departure Time. ADVS is Advisory Service. Let's continue. ADZ means Advise. AES is Aircraft Earth Station — the satellite terminal on the aircraft. AFIL is a Flight Plan Filed in the Air — you file it while already airborne. AFIS is Aerodrome Flight Information Service, the service that provides information and alerting at an aerodrome without a full control tower. AFM means Yes, Affirm, Affirmative, or That is Correct — it's the positive response. ALR is Alerting as a message type designator. ALRS is Alerting Service. ALS is Approach Lighting System. ALT is Altitude. ALTN can mean Alternate or Alternating when referring to a light that changes colour, and also Alternate for an alternate aerodrome. AMA is Area Minimum Altitude. AMD means Amend or Amended, used for amended meteorological messages and as a message type designator. AMDT is Amendment, specifically an AIP Amendment. Now for more. AMS is Aeronautical Mobile Service — the radio service between aircraft and ground stations. AMSL is Above Mean Sea Level, the standard reference for altitude. AMSS is Aeronautical Mobile Satellite Service. ANM is ATFM Notification Message. ANS is Answer. AO is Aircraft Operators. AOC can mean Aerodrome Obstacle Chart or Air Operator Certificate — two very different things, so context matters. AOD is Above Ordnance Datum (Newlyn) — that's a specific vertical datum used in the UK, based on mean sea level at Newlyn, Cornwall. AOM is Aerodrome Operating Minima, the minimum weather conditions for operations at an aerodrome. AP is Airport. APAPI is Abbreviated Precision Approach Path Indicator — a simplified version of the PAPI lights. APCH is Approach. Continuing through the list. APHAZ is Aircraft Proximity Hazard. APIS is Aircraft Positioning and Information System. APP is Approach Control Office, Approach Control, or Approach Control Service. APR is April. APRX means Approximate or Approximately. APSG is After Passing. APV means Approve, Approved, or Approval. ARFOR is Area Forecast in aeronautical meteorological code. ARNG is Arrange. ARO is Air Traffic Services Reporting Office — the office where you file flight plans and get briefings. ARP can mean Aerodrome Reference Point or Air Report as a message type designator. ARQ is Automatic Error Correction. ARR means Arrive or Arrival, and also Arrival as a message type designator. ARS is Special Air Report as a message type designator. ARST is Arresting, used to specify part of aircraft arresting equipment. Now the weather and runway terms. AS is Altostratus, a cloud type. ASC means Ascent to or Ascending to. ASDA is Accelerate-Stop Distance Available — the runway length available for the accelerate-stop distance. ASPH is Asphalt. AT... means At, followed by the time at which a weather change is forecast to occur. ATA is Actual Time of Arrival. ATC is Air Traffic Control in general. ATD is Actual Time of Departure. ATFM is Air Traffic Flow Management. ATIS is Automatic Terminal Information Service — the continuous broadcast of aerodrome information. ATM is Air Traffic Management. That covers the first page of definitions. These acronyms will appear in every document, every NOTAM, every AIP amendment you read. Take your time with them — you don't need to memorise all at once, but you do need to recognise them when they appear.