This is an extract from the
FCOM3 A-319\320 Operating Limitations 3.01.34 p1
of one of Russian airline.
"It is not recommended to use TCAS II (ACAS) TA/RA mode in flight in former USSR airspace. When ТА mode is selected, pilots should coordinate actions with the АТС. In the former USSR airspace, aircraft can only fly on routes covered by АТС ground facilities, using RBS mode."
Looks strange (at least).
Every flight I brake this "limitation".
