Principles & services

090 CommunicationsChapter 1

Core principles

Key fact

Standard language is English. Standard abbreviations should be used. If no reply is received, wait 10 seconds before retrying.

Definition — Duplex

Two-way communication can be established simultaneously in both directions. Air/ground communications are considered two-way duplex (Austro).

Definition — Simplex

Two-way communication takes place in one direction at a time — only one station transmits while the other listens.

Definition — Aeronautical station

A land station in the aeronautical mobile service (or, in some cases, a ship or platform at sea).

Service availability codes

Code	Meaning
H24	Continuous day and night service
HJ	Sunrise to sunset (Jour)
HN	Sunset to sunrise (Nuit)
HO	During operating hours
HS	Service available during scheduled operational hours
HX	No specific working hours
HR	Hours (refer to published times)

Key abbreviations

Abbreviation	Meaning
ATIS	Automatic Terminal Information Service
ACARS	Aircraft Communication Addressing and Reporting System
SAR	Search and Rescue
CTR	Control Zone
STAR	Standard Instrument Arrival
APV	Approach Procedures with Vertical Guidance

Definition — Instrument approach

From the Initial Approach Fix (IAF) or a defined arrival route to a point where a landing may be completed (and a missed approach initiated if required).

ATS services at an airport

Unit	Role
Tower	Aerodrome control service
Ground	ATC on the manoeuvring area
Delivery	Pre-departure clearances
Information	Flight Information Service (FIS)

Other services

Unit	Role
Apron	Aircraft guidance by the airport
Dispatch	Communications from the operator

ATC unit designations

Without radar

Unit	Service
Control	Area control service
Approach	Arrival and departure control service

With radar

Unit	Service
Radar	ATC service
Departure	Departure control service
Arrival	Arrival control service
Director	Control service on final approach with precision radar

Service categories

Key fact

Three categories of aerodrome communication service: Air Traffic Control Service (ATC), Aerodrome Flight Information Service (AFIS), and Aerodrome Air/Ground Comms (A/G).

Definition — AFIS

Provided to give information for safe and efficient conduct in the ATZ. Delivered by qualified Flight Information Service Officers. Can give instructions on the ground (including helicopters).

Definition — A/G

Provided by AGCS operators. May only give information — not instructions. Uses the suffix “Radio”.

Exam trap

AFIS can give ground instructions; A/G may only give information. A/G stations use the suffix “Radio” in their callsign.