Radio and Hand Signals
Radio is used in formations of more than two aircraft, or when the Lead
      believes that Wing will not be able to discern a hand signal. Radio format is,
          [Callsign], [action required], go
. When in
      echelon, compliance is the only acknowledgement necessary. When there is a formation change
      where the Lead cannot see all aircraft, the last aircraft in the configuration should confirm
      the completion of the change with the call, [Callsign], in
.
The overriding factor in all cases is that there must never be any possibility of ambiguity in a formation.
When communicating with other air or ground stations the aircraft leading at the time will make all necessary radio calls on behalf of the formation.
