Sorry for the desinformation i gived to you.
Please, disregard my first message.
I have recent experience with Alcatel equipment, and the procedure in case of fault BCCH TRX lasts for 2 to 3 minutes, during which the calls on TRX2 are disconnected and the frequency is changed to the BCCH ARFCN.
Maybe with other vendors the procedure is different, i don’t know…
Regards
Chefo