A320 fire protection system

[Shatwa07]

Any idea how to determine which loop is the faulty one before consulting the AirNav ..
by experience?

[Station Zero]

If an active fault, should have a ECAM Fire Loop A/B message. Then can verify by CFDS, system report test, ATA 26, and run a FDU test for either engine or the APU, which should give a failure code that will identify the applicable TSM procedure to follow.