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Air Operator Designators and Call Signs

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Domestic two-letter designator (2LD)
ICAO three-letter designator (3LD)

Process to apply for a designator and call sign

Operators with numerous flights that operate in more than one flight information region or internationally may qualify to be assigned a designator and call sign. Designators and call signs are used when an operational need exists as supported by a business case and confirmation from NAV CANADA operations.

During the application process, NAV CANADA verifies the information provided by the applicant and does an initial check to determine whether the requested call sign conflicts with any known call signs. In the event call sign confusion occurs or safety is compromised, NAV CANADA will initiate action. In some cases, operators may need to change their designator / call sign.

  • Air operator designators are only approved for use by Canadian air operators with a valid (Air or Private) Operating Certificate (i.e. CAR 604 or Part VII) or for the purpose of providing Aeronautical Fixed Telecommunication Network (AFTN) services.
  • The same designator will not be registered for, or used by, more than one aircraft operating agency, aeronautical authority or service.
  • No more than one designator or call sign will be registered for, or used by, each air operator, aeronautical authority or service.
  • When a designator is no longer required, NAV CANADA should be informed immediately. Any such designator so released will not be reassigned for at least 60 days.

  • The call sign should resemble the name of the aircraft operator or its function and be distinct and dissimilar from any other already assigned.
  • In order to reduce the length of transmission the call sign should be brief, comprising if possible of one word of two or three syllables. It should not exceed two words.
  • Air operator designators may not be used in phonetic form as call signs, however, those of long standing may be retained provided an acceptable alphabetical representation is used (e.g. KLM or KAY DEE).
  • Call signs that represent aircraft manufacturers or types may not be used.
  • Designators ending in “I”, “O” and “Z” are to be avoided due to potential confusion with the numbers “1”, “0” and “2”.

In the selection of the flight number the following is recommended:

  • Flight numbers should be kept as short as possible and usually be limited to three figures; keeping in mind the entire flight ID must be less than 7 alphanumeric digits.
  • Flight numbers should be selected bearing in mind the flight numbers already in use by other operating agencies in the intended control environments.
  • When practicable flight numbers other than those ending in a zero or five should be used.

Flight numbers used by Canadian air operators are not subject to approval. However, for flight planning purposes, the flight identifier, including the designator, must be a minimum of three and a maximum of seven characters.

  • The requested call sign
  • The name and address of the company
  • The name and contact information of a person authorized to represent the company
  • A list of the fleet the company operates including the aircraft type and civil aircraft registrations (NAV CANADA will use this information to verify flight activity)
  • A business case stating the operational need for a designator
  • A complete copy of the Private or Air Operating Certificate issued by Transport Canada, or a legal corporate document if only applying for an AFTN address
  • A copy of their flight schedule or flight log indicating the average number of flights per week. As a guideline, NAV CANADA will consider operators with a minimum number of 20 flights per week.


Remotely Piloted Aircraft (RPA) operations conducted at or below 400ft AGL or involving small RPAs (under 25kg) will not be assigned a designator. Exceptions will apply based on special RPAS operation requests affecting controlled airspace (e.g. RPA operating under an SFOC). Only RPA operations that require air traffic services (ATS) or will communicate with ATS via a means of communication acceptable to NAV CANADA will be considered, provided the aircraft and operator are adequately equipped. In these cases, the need for a designator will be assessed on a case-by-case basis.

Domestic two-letter designator

Domestic two-letter designators and call signs are intended for use by Canadian aircraft operators engaged in private or commercial air services (i.e. CAR 604 or Part VII), solely flying in Canadian domestic airspace and which, in the opinion of NAV CANADA, have a need for an exclusive designator.

ICAO three-letter designator

ICAO three-letter designators and call signs are intended for use by air operators, as well as aeronautical authorities and services that operate aircraft internationally and over the AFTN network. This includes transborder flights with the U.S.

NAV CANADA is designated as the focal point for the assignment of ICAO designators to Canadian aircraft operators. We ask that operators requesting an ICAO designator contact the NAV CANADA focal point first and provide us with a list of suggested call signs so we can check them against all known call signs, both civil and military.

On behalf of ICAO, NAV CANADA ensures due diligence in checking for the validity of the aircraft operator or aeronautical service. This process allows NAV CANADA to have current and accurate information for the operators and services who exercise the privilege of using a unique flight ID and call sign for their operations.

For more information or to apply for a designator, please contact:

NAV CANADA Customer and Stakeholder Services
151 Slater Street
Suite 120
Ottawa, ON K1P 5H3

Tel.: 1-800-876-4693