Cockpit Voice Recorder (UAL) 747-400
Mike Ray's simulator and checkride manual and the UAL FM mention, in the initial cockpit preparation checklist, a test of the CVR *before* any power is applied to the aircraft (push and check for deflection). Does the United CVR have a battery that powers the test or is there another electrical source available for the test?
I've only heard of CVR's on AC Bus 1 or 3.
Rgds.
NSEU