Similar Call Signs

Similar Call Signs

What have we been informed

  • There has been an increasing number of similar call signs instances reported to EUROCONTROL. The reports are provided within the voluntary safety incident reporting and data sharing initiative.
  • The use of similar call signs by aircraft operating in the same area on the same RTF frequency often gives rise to potential and actual flight safety incidents.
  • The danger of an aircraft taking and acting on a clearance intended for another is obvious. The following are some of the potential outcomes of such a situation:
    • the aircraft takes up a heading or routing intended for another;
    • the aircraft commences a climb/descent to a level to which it has not been cleared (Level Bust);
    • the aircraft leaves the appropriate RTF frequency (Loss of Communication);
    • in responding to a message, the aircraft blocks a transmission (Blocked Transmissions / Undetected Simultaneous Transmissions (USiT));
    • the intended recipient does not receive the clearance, and fails to take up the desired heading or routing, or fails to climb or descent to the cleared level;
    • the controller misunderstands the intentions of aircraft under his/her control;
    • the controller issues a clearance to the wrong aircraft, and/or fails to issue a clearance to the intended aircraft;
    • the workload of controllers and pilots is increased because of the necessity to resolve the confusion.
  • Recognising the risk associated with similar call signs, EUROCONTROL is investigating the possibility of implementing system solutions aimed at removing the risk potential as early as the flight planning phase and by involvement of Central Flow Management Unit (CFMU).

European Action Plan for Air Ground Communications Safety


© European Organisation for Safety of Air Navigation (EUROCONTROL) October 2007. This alert is published by EUROCONTROL for information purposes. It may be copied in whole or in part, provided that EUROCONTROL is mentioned as the source and to the extent justified by the non-commercial use (not for sale). The information in this document may not be modified without prior written permission from EUROCONTROL. The use of the document is at the user’s sole risk and responsibility. EUROCONTROL expressly disclaim any and all warranties with respect to any content within the alert, express or implied.


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