Originally Posted by PVDtoDEL

As long as TAS uses Troya as the DCS (true at all stations except those where the airport mandates a different DCS), it won't be a problem for TK in TAS to check the bag through to LHR and issue both boarding passes, even across two PNRs. TK has done it for me many times, even in situations where one of the segments is confirmed but the other segment is standby.