Jump to Content
Mode Aviation
Reference No. AR201500081
Date reported 01 October 2015
Concern title The use of flight number call signs in Australia
Concern summary

The concern relates to the use of flight number call signs in Australia.

Industry / Operation affected Aviation: Air transport
Concern subject type Aviation: Air Traffic Control

Reporter's concern

The reporter expressed a safety concern regarding the pronunciation of flight number call signs (call signs) in Australia where call signs are transmitted using Group Form [the pronunciation of a series of numbers as a whole number, or pairs of numbers, as opposed to pronouncing each individual number].

The reporter is aware that Australia is has filed a difference with ICAO in relation to Annex 10 Paragraph, and     

The reporter advised that they have noticed numerous call signs on the same frequency, which when pronounced in this way, the numbers are so similar that the pilots and controllers have, for safety reasons, reverted to the old method of pronouncing the flight number in single digits.

The reporter advised that discussions with current and retired air traffic controllers have suggested that a return to the old procedure, of pronouncing each number individually, would be a safer option. The reporter also added that going back to numeral based pronunciation in many cases uses fewer syllables and actually reduces air-time used up.      

The reporter also advised that call sign confusion is a known issue throughout the world and Evair the EUROCONTROL Voluntary ATM Incident Reporting organisation has developed a computer program which aids individual organisations to de-conflict call signs within their own organisations - maybe this could be looked at in an Australian context.

Operator's response (Operator 1)

In relation to the suggestion to return to a historical practice of pronouncing each number individually, Australia trialled the use of flight number call signs in 1997 and commenced broader usage in 2001. During implementation, the use of Group Format was identified as a safety requirement to reduce the possible confusion with assigned flight levels or headings. As such, the requirement to use Group Format was placed on operators wishing to use flight number call signs.

As previously reported to the ATSB, Airservices has established a process to monitor and increase awareness of reported call sign confusion issues. The process involves reviewing the call sign confusion occurrences reported via our safety reporting system and notifying relevant airlines of the reported occurrence. In addition, Airservices provides a call sign conflict report to domestic aircraft operators each month.

Regulator's response (Regulator 1)

CASA has reviewed the REPCON and considers that the response from Airservices, and the action taken by them, is appropriate. Call sign confusion be managed with existing procedures by Airservices.

Share this page Comment
Last update 18 April 2016