rudder,
Yes, that is a great tool for dispatch pre-flight check requirements.
I was referring to in-flight, when the pilot is required to verify real time RAIM.
Depending on the model, variant of the FMS, different things can happen. On the MCDU PROG page, you can see the predictive GPS req'd, estimated, and accur values. Checking the 'estimated' value enroute will let one know what may be expected on approach. If the value is not enough the unit will have issues going to approach mode.
The different boxes have different features with a hybridized HIL that estimates when GPS integrity falls below certain limits, creating an 'equivalent' HIL, but for short amounts of time, which differs depending on equipment.
What I was also looking at was some of the rest of the posts that were talking about "PRIMARY LOST" or "GPS UNAVAIL", if the pilot was looking at the page for the explanation.
umm... I will leave this up if it helps, but I just realized the issue, there are 2 very similar threads on this in Tech Log, and I was responding to the wrong thread..sorry about that. 