wiggy says: "Smoke Removal and various versions of Cabin and/or flight deck Smoke and Fire drills often call at some point for electrical power to be removed from items (either by a switch or by disconnecting busbars) in order to try isolate the source of the problem.
Do you consider such drills 'far fetched' or 'daft'? "
So far, we have lost two aircraft and their passengers. That is a high price to pay. We may have lost them anyway. Certainly, this crucial circuit should not interfere with drills; with good design, it does not need to.