Should the KLN94 withdraw lateral guidance if that happens?
Loss of RAIM certainly does not do anything during cruise - so long as adequate GPS reception is retained.
Today, I got a loss of reception message, with a MSG (message) annunciation. The deviation bar on the EHSI disappeared. I pressed MSG to read the message, and it said something about loss of RAIM. Obviously I was busy so I didn't catch it, but I wonder if a loss of RAIM during an approach causes the box to throw away the guidance?
I think it does and depending on where you were in the approach it probably means RAIM was lost some time earlier. the MSG is suppressed after the FAF I think for something like 5 minutes.