Implementation Guidance for SELCAL 32

With the ICAO Communications Panel approving the global implementation of SELCAL 32 for the 30 Nov 2022, ANSPs and aircraft operators should now be considering the necessary steps to be compatible with the ICAO SARPs amendment.  The below provides some high-level guidance to each group.


ANSPs will need to consider the implementation of the SELCAL code pool expansion on their flight planning systems and any other systems that support the SELCAL system. Several implementation options are available, including:

  • Contact SELCAL encoder supplier to include the extra tones in the existing encoder
  • Update to a new encoder on existing HF transmitters.
  • Install a new PC based encoder

RTCA DO-93A also includes specific information for ground stations that ANSPs should be aware of.

ASRI has confirmed that the below manufacturers have SELCAL 32 compliant equipment available for ground transmitter and dispatch consoles (please speak direct to the manufacturer to verify which equipment is current)*:

*ASRI and ICAO do not endorse any specific manufacturer or solution 

Aircraft Operators

Airlines will need to evaluate the impact that the SELCAL code pool expansion may have on their airframe and ground systems including flight planning when new aircraft are added to their fleets that support the expanded SELCAL code pool functionality.

Airbus and Boeing are expected to begin offering the SELCAL 32 functionality on new aircraft being delivered after the 2020 time-frame, with some existing aircraft being already compatible with suitable software updates.  Queries on airframe compatibility should be addressed directly with the airframe manufacturers.