A couple of questions about the CVR:
(a) Does the CVR record even when absolutely no voice input is being fed into it? For example, if there was complete silence for the last 5 hours of the flight, would it actually record this silence for the final 2 hours?
(b) If the CVR was disabled, would it continue to contain data from the previous 2 hours up to the point it was disabled? Or does disabling it cause the data to be wiped?
(a) Yes - it records continuously. The aircraft sounds are just as important as voice input. Typically there are 4 tracks - cockpit area mic, Capt mic, FO mic and I think 3rd Crew mic?
(b) Yes, but disabling it is only possible by pulling the CB, which in the T7 is in the E/E compartment. It is possible to erase the data, but that is only possible when on ground (WOW) and the engines are both shutdown.