What changes have been made to ICAO Annex 10 volume IV (Surveillance Radar and Collision Avoidance Systems) between amendment 85 and amendment 89?

I only have access to amendment 89, but I have some material referring to amendment 85. What is the difference between these versions, what has been changed to ICAO Annex 10, volume IV by amendments 86 - 89?

  • 1
    $\begingroup$ I've got copies of both Amdt 87 and Amdt 89. Amdt 87 shows no change from 85. Amdt 89 does show changes, but the summary of changes is "Surveillance systems". I couldn't see any changes at the Table of Contents level, but there are numerous small changes throughout. $\endgroup$
    – Gerry
    Nov 30, 2017 at 19:07
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    $\begingroup$ @mins Thanks. That list answers DeltaLima's question as Amdt 89 is the only change after Amdt 85. $\endgroup$
    – Gerry
    Nov 30, 2017 at 19:42

1 Answer 1


With help of Gerry and Mins, it became clear that Amdts 86,87 and 88 did not introduce any changes to Volume IV of Annex 10.

Therefore any differences between Annex 10 Vol. IV Amdt 85 and Amdt 89 would be introduced by Amendment 89. From this documentPDF it can be seen that the changes were distributed in state letter 2014/21.

Digging a bit further I found the minutes of an ICAO Communication Navigation and Surveillance Sub-Group (CNS SG)PDF meeting which included the state letter in Appendix B. You can find it from page 56 to 91.

Amendment 89 contains over 30 pages of changes to Volume IV of Annex 10 and that was more than I had hoped for; needless to say I am not copying all that information into this answer. A summary of changes can be found below.

  • General changes

    • Various recommendations and clarifying notes added.
    • Various editorial changes
  • Chapter 3, Mode S Surveillance

    • Revoking of the Mode A/C/S all-call interrogations after 1 January 2020.
    • Introduction of new data parity overlay ("Modified AA") in transponder and Overlay Control (OVC) bit in Mode S uplink protocol.
    • Changes to Type Control (TCS)
  • Chapter 4. Airborne Collision Avoidance System

    • No significant changes
  • Chapter 5. Extended Squitter (ADS-B)

    • Introduction of ADS-B 1090ES Version 2
  • Chapter 6. Multilateration

    • Spectrum protection requirements

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