AIM - COM 5.8.1 Call Signs/Civil Aircraft

In radio communications, the registration letters of an aircraft call sign must be
expressed in phonetics at all times.

The word “heavy” is used to indicate an aircraft capable of a takeoff weight of
300,000 lbs or more.

After communication has been established and when no likelihood of confusion, the
word “heavy” may be omitted and callsigns may be abbreviated.

A “MEDEVAC” is a flight responding to a medical emergency for the transport of
patients, organ donors, organs or other urgently needed lifesaving medical material.
This can also apply to certain medical flights, generally helicopters, which may be
designated as Air Ambulance Flights.

Canadian Air Carriers:

    (a)     Initial contact: The operator’s radiotelephony call-sign followed by:
            the flight number, or
            the last four characters of the aircraft registration, and
            the word “heavy” if applicable.

Example:     Air Canada 149 Heavy (AIR CANADA ONE FOUR NINE HEAVY).

    (b) Subsequent communications: No abbreviations permitted except that
        “heavy” may be omitted.

Foreign Air Carriers:

    (a) Initial contact: The operator’s assigned radio telephony call-sign followed
        by the flight number, or the full registration of the aircraft, and the word
        “heavy” if applicable.

Example:     Speedbird GABCD Heavy (SPEEDBIRD GOLF ALFA BRAVO
CHARLIE DELTA HEAVY)

    (b) Subsequent communications: Where the aircraft registration is used, it may
    be abbreviated to the radiotelephony designator and the last two characters.

Example:     Speedbird CD (SPEEDBIRD CHARLIE DELTA).

Canadian Private Civil Registration and Canadian or Foreign Carriers Without an
Assigned Call Sign

    (a)         Initial contact: The manufacturer’s name or the type of aircraft, followed
                 by the last four letters of the registration.

    Example:     Cessna GADT (CESSNA GOLF ALFA DELTA TANGO).
                      Aztec-FADT (AZTEC FOXTROT ALFA DELTA TANGO).

    NOTE:     The words helicopter, glider or ultralight are an acceptable substitute to
                    the type of aircraft.

    (b)        Subsequent communications may be abbreviated to the last three letters of
                the registration, if this abbreviation is initiated by ATS.

    Examples:     Cessna GADT becomes “ADT” (expressed: ALFA DELTA TANGO).
                        Aztec-FADT becomes “ADT” (expressed: ALFA DELTA TANGO).

Foreign Private Civil Registration:
   
    (a)         Initial contact: The manufacturer’s name or the type of aircraft, followed
                 by the full aircraft registration.

    Example:     Mooney-N6920K (expressed: MOONEY NOVEMBER SIX NINE
                      TWO ZERO KILO).

    (b)         Subsequent communications may be abbreviated to the last three characters
                 of the registration if initiated by ATS.

    Example:     Mooney-N6920K becomes 20K (expressed: TWO ZERO KILO).
                      
Medical Evacuation Flight (MEDEVAC)

    (a)         Initial contact: The manufacturer’s name or type of aircraft or company call
                 sign followed by:
   
            (i)  the flight number and the word MEDEVAC, or
            (ii) the last four characters of the aircraft registration and the word
            MEDEVAC.

    Examples:     Austin 101 MEDEVAC (expressed: AUSTIN ONE ZERO ONE
                        MEDEVAC).

                        Cessna FABC MEDEVAC (expressed: CESSNA FOXTROT ALFA
                        BRAVO CHARLIE MEDEVAC).

    (b)         Subsequent communications: May be abbreviated as per normal
                 procedures retaining the word MEDEVAC.