IF you have BCCH missing, your TRX is OFF.
Transmission PCM: You have BCCH missing on all TRX with PCM failure.
TRX is out: bcch missing + lap D failure
Ross feeder is bad: bcch missing + tx antenna performance degraded
Bad TRUA: your trame is not good, check routing Time slot. (only after operation)
After a reset site, you have Bcch missing during a short moment.