An Aircraft CALL SIGN is a group of alphanumeric characters used to identify an aircraft in air-ground communications. It is a unique identifier assigned to an aircraft for ease of identification during communication.
TYPES OF AIRCRAFT CALL SIGN
According to ICAO, there are three different types of aircraft Call Sign as follows:
👉 Type A – The characters corresponding to the registration marking of the aircraft (e.g. ABCDE). The name of the aircraft manufacturer or model may be used as a prefix (e.g. Airbus ABCDE);
👉 Type B – The telephony designator of the aircraft operating agency, followed by the last four characters of the registration marking of the aircraft (e.g. Rushair BCDE);
👉 Type C – The telephony designator of the aircraft operating agency, followed by the flight identification (e.g. Rushair 1234).
Flight identification may be the ‘public’ flight number used for ticketing and aircraft handling, or it may be an alternative unique alphanumeric string. Also, the “telephony designator of the aircraft operating agency” will, in airline use, be the designator of the company for whom the flight is being operated, which may not be the operator of the aircraft. In any case, the full call sign must be used when establishing communications.
ABBREVIATION OF CALL SIGN
After satisfactory communication has been established, abbreviated call signs may be used provided that no confusion is likely to arise. However, an aircraft must use its full call sign until the abbreviated call sign has been used by the ground station. Call signs may be abbreviated only in the manner shown below:
👉 Type A – The first character of the registration and at least the last two characters of the full call sign (the name of the aircraft manufacturer or model may be used in place of the first character);
👉 Type B – The telephony designator of the aircraft operating agency, followed by at least the last two characters of the call sign;
👉 Type C – No abbreviated form.
Most airline call signs belong to Type C for which there is no abbreviation. Therefore, abbreviations such as “1234” or “Rushair 34” are not permissible. An aircraft is not permitted to change its call sign during flight, except temporarily on the instruction of an air traffic control unit in the interests of safety. In order to avoid any possible confusion, when issuing ATC clearances and reading back such clearances, Controllers and Pilots must always add the call sign of the aircraft to which the clearance applies.
In addition to Call Signs being used by Flight Crews and Air Traffic Control to identify individual flights during radio communication, it is also used to identify aircraft on the controller’s screen (RADAR). A call sign may or may not match the flight number and some airlines have radio call signs (telephony designator) that differ from the airline’s name. While a flight number is different from a call sign, it may still form part of or match the call sign in some instances.
A passenger airline ticket is sold with IATA standards/rules and carries the flight number, which is a specific code assigned by an airline to a particular flight in its network. A flight number comprises two character – IATA airline designator and 1 to 4 digits assigned by the airline for a specific service. On the other hand, the Pilot is flying the aircraft with ICAO standards/rules, which means flying with call sign. Most airlines have both a three-letter ICAO code (used for call sign) and a two-letter IATA code (used for flight number).
Examples
🟢 For Ibom Air first flight from Uyo to Lagos
Flight number – QI4100
Call sign on RADAR screen – IAN4100
Radio call sign or telephony designator – IBOM 4100
QI is IATA code, IAN is ICAO code and IBOM is the airline radio call sign.
🟢 For Air Peace flight from Lagos to Uyo
Flight number – P47140
Call sign on RADAR screen – APK7140
Radio call sign or telephony designator – IBOM 4100
QI is IATA code, IAN is ICAO code and IBOM is the airline radio call sign.
🟢 For Air Peace flight from Lagos to Uyo
Flight number – P47140
Call sign on RADAR screen – APK7140
Radio call sign or telephony designator – Peace Bird 7140
P4 is IATA code, APK is ICAO code and PEACE BIRD is the radio call sign
REFERENCES
ICAO Annex 10
