worries in the mornin'
once again i'm coming to the conclusion, that my B738 manuals are just poor in terms of beyond-basic-layout info.
i mean I DO KNOW those cargo holds are cat C, supposed to be absolutely fire proof untill the crew reaches the next hotel bar. and they are not ventilated. 'used' cabin air and 'used ' eq. cooling air (inflite overboard ehaust valve closed) flows "around the linings" so those dogs etc don't freeze solid.
and the holds DO HAVE some very small pressure exchange mechanism to the outside.
and if u turn one pack off in flight the left recirc quits.
and on the newer B738 in the event of a fwd cargo smoke detection (by the way those cargo 'fire' detectors are only smoke detectors) the eq cooling exhaust fan will stop running while the off-light will be inhibited.
BUT WHY?
air flowing AROUND the cargo hold won't influence some fire on the inside?!?