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Mode Aviation
Reference No. AR201500079
Date reported 23 September 2015
Concern title Similar call signs operating near Brisbane
Concern summary

The concern related to a number of flights which are arriving and departing from Brisbane with a similar call sign

Industry / Operation affected Aviation: Air transport
Concern subject type Aviation: Airspace

Reporter's concern

The reporter expressed a safety concern related to the potential confusion resulting from the use of similar call signs by a number of flights departing and arriving at from South East Queensland.

The reporter advised that there is a potential conflict between two flights using the same flight numbers with their airline designator – one operating to Brisbane and one operating to the Gold Coast and both arriving around the same time.  

These two flights are occasionally in the same sequence, in close proximity and in a complex airspace area, more so when the restricted areas between FL180 and FL250 are active (generally several times a day).  

The reporter also advised that there is a potential confusion between a number of flights all departing Brisbane around the same time.

The return flights arrive in close order each morning.

The reporter has noted several recent confusions involving these flight numbers and the flight crews appear to be aware of the issues and are reverting to the use of individual numbers when they first contact ATC.

The reporter suggests that the question of call sign pronunciation should be re-examined against the old use of pronouncing each numeral separately.

Operator's response (Operator 1)

This flight number has been used on the [location]-Brisbane route on the current schedule for an extended period and the preference is to retain the flight number.

A review of our safety database has not identified previous reports highlighting call sign confusion between these two call signs, but an Internal NOTAM will be appended to the company flight plan in order to heighten crew awareness.

Scheduling have advised that at the next change of season the flights with similar call signs scheduled departures will be amended, further decreasing the likelihood of call-sign confusion between these aircraft.

Operator's response (Operator 2)

The reporter suggests that the question of call sign pronunciation should be re-examined against the old use of pronouncing each numeral separately. This relates to the procedure documented in AIP GEN 3.4 Flight Number Call signs – Using Group Form. We are obliged by legislation to follow procedures documented in AIP and expresses no opinion on the preference either way. It is suggested that this report be referred to Airservices Australia for further comment.

We are reviewing the allocation of the specific flight number as it is noted that both airlines are operating in proximate airspace.

Regulator's response (Regulator 1)

CASA has reviewed the REPCON and notes the corrective action from the airlines.

CASA also notes that this REPCON and two others recently reviewed appear to have been submitted by air traffic controllers. Airservices should also be managing such occurrences on a case by case basis in accordance with their Civil Aviation Safety Regulations 1998 Part 172 authorisation as an Air Traffic Services (ATS) provider.

Airservices is required to comply with International Civil Aviation Organization Procedures for Air Navigation Services – Air Traffic Management (PANS-ATM – Doc 4444), which has a specific section dealing with call sign similarity resulting in confusion:-

  • 15.7.5 Change of radiotelephony call sign for aircraft.
  • An ATC unit may instruct an aircraft to change its type of RTF call sign, in the interests of safety, when similarity between two or more aircraft RTF call signs are such that confusion is likely to occur.
  • Any such change to the type of call sign shall be temporary and shall be applicable only within the airspace(s) where the confusion is likely to occur.
  • To avoid confusion, the ATC unit should, if appropriate, identify the aircraft which will be instructed to change its call sign by referring to its position and/or level.
  • When an ATC unit changes the type of call sign of an aircraft, that unit shall ensure that the aircraft reverts to the call sign indicated by the flight plan when the aircraft is transferred to another ATC unit, except when the call sign change has been coordinated between the two ATC units concerned.
  • The appropriate ATC unit shall advise the aircraft concerned when it is to revert to the call sign indicated by the flight plan.

CASA recommends that Airservices are included as a respondent to future REPCONs of this nature. If the reporter appears to be an air traffic controller, it would be advisable that they submit a report to the Airservices incident reporting system.

ATSB comment

As suggested by CASA, REPCON forwarded this report to Airservices Australia and received the following response:

In response to a similar concern reported previously [AR201500050], 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. Airservices confirms that the process was followed for this reported concern.

Airservices has also incorporated the relevant risk mitigation measures as published in the Aeronautical Information Publication (AIP) into the Manual of Air Traffic Services (MATS) to improve the visibility of risk mitigation measures available to controllers in managing similar call signs.

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Last update 19 November 2015