Thanks Art, makes sense.
However, the main tank was not empty and both Xfer pumps have been tested by the AAIB, so if CAD had failed then surely as a matter of importance you would leave the Xfer pumps on?
We know the reds came on, but as you stated in your previous post you have witnessed failures of these which shows unreliability of the system, perhaps they came on too late and 10 mins was not available! The testing you saw did they run till indicated zero or flameout? Means the difference between a faulty low level device or a faulty probe system.
I'm trying to work out why the prime pumps would be switched purposely on, or if they were left on. If say 2 mins aftert the red came on one engine started showing symptoms of fuel starvation maybe the prime pumps were activated?
FS