AP troubles on ILS

[wrgway]

After solving some software issues with my 430/Sorcerer I was anxious to try out the ILS /LOC mode in flight. All went well on the approach with localizer locked on and tracking nicely while we approached underneath the GS. AP announced GS armed and at the center of indicator (AFS 3500) AP announced GS coupled and we started down. Shortly after that I noticed the glide slope bug start to slip down below center and realized the AP had switched back to "Altitude hold mode" In talking with Trutrack it sounds like the 430 which feeds directly to the AP is dropping the GS signal. Anyone else see something like this? Any ideas? Any input is appreciated as always.
Thanks,
Don

 

[Tom Martin]

Is it possible that your minimum bug was set too high?

 

[flyinga]

If your unit is a 430W, you could try shooting an RNAV approach with verticle guidance on the autopilot. This glideslope for one of these approaches is computer generated by the 430W and has nothing to do with the ILS GS. Perhaps you could then determine if it is a GS reception problem or an autopilot problem.

 

[wrgway]

The minimums bug on the AFS isn't active unless you're controlling the approach from the AFS is it? I'll double check that as it makes perfect sense as the GS uncoupled at about the same point on 2 totally different ILS's. I've been using the GPS advisory GS on those approaches for a while and they all work perfectly. Spoke to Trutrak and they seemed to think it was a 430 or antenna problem. Lucas is great for service and even offered to bring the unit back and check it over but I just don't think it's AP problem. I'm heading over to the hanger in the morning to take a look at he minimum's bug setting.