Originally Posted by
dream747
You need the batteries to start the APU. The batteries pb must be in the auto position to start the APU even if external power is connected. Otherwise it will not start. And there is no fire protection.
Also, refer to the MEL for the said fault directs you to start the engines with external power and do not start the APU.
But the BAT are in AUTO position, even after the fault triggers. In fact the fault has no ECAM actions. It is just crew awareness. Secondly my understanding of the MEL was because it allows you to operate with APU inop for 10 flights, the manufacturer doesn't want you to drain your batteries by starting the APU every time. Last of all, according to the MEL preamble you're supposed to only use the MEL procedure which is valid for that phase of the flight. Since the procedure Don't start the APU is a part of Flight preparation in MEL, and you being already in the flight phase you're not required to adhere to it.
Can you please specify where in the FCOM does it say that there is no fire protection with the BCL not working ?