I have to admit to being extremely surprised by this thread, having just finished a load of exams for which I was taught that, where an aircraft has a single fire extinguisher, it must be BCF, and where an aircraft has more than one fire extinguisher, at least one must be BCF.
However, I should add that my class were informed that the CAA have removed from the exams all questions about which type of fire extinguisher is to be used in a given situation, because there was so much debate about the answers.
Not a subject I particular want to discuss, though, having dropped at least two marks on the Operational Procedures exam because I couldn't remember how many extinguishers are required on anything with between 31 and 200 pax seats
FFF
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