GNS 530/430 losing contact

[tttocs 301]

I've recently begun simming again after a couple of years break and am reminded of an old problem I've had for some time that I'm hoping someone can shed some light on.

 

I have the 530, 430 and unlimited pack, but this will occur in planes with just one or the other installed, as well as planes with both running.  Periodically, the unit acts almost as if it loses GPS satellite contact.  Data fields (Ground speed, bearing, ETE, etc.) go blank, the unit(s) will stop driving whatever Nav display is being used (HSI, CDI...) and if the autopilot is coupled it will begin to wander.  Often, I'll also get terrain the "Terrain not available" audio warning.  This will pop back and forth between having signal and not having signal for several minutes before returning to normal.  In most cases, this is a minor irritation, but the other day I was in IMC in the middle of a GPS (LPV) approach when this occurred, which is a bit more frustrating.

 

Any suggestions?

 

Scott

[RXP 2,336]

From one point of view, this sounds like the ultimate GPS simulation with GPS receiver failing with thick and bad weather...

 

In fact, this sounds like a Garmin trainer issue where it fails to 'compute' under some circumstances. We have not totally identified the reasons yet, we are like you've said sporadic, but we are looking actively.

 

Mind you, the new GNS WAAS simulation product is entirely rewritten from scratch and it will be easier for us to track these kind of trainer bugs. One example of such bugs: try a RAIM check with the trainer... Our last GNS WAAS for XPlane update (v1.8) now corrects the trainer bug internally, the new GNS WAAS as well!

[tttocs 301]

Thanks for the response Jean-Luc.  I agree that this acts more like a trainer issue than anything in your code as it's not like the unit goes dark from within the sim, but more like the trainer simulation itself is randomly losing the simulated satellite array.  Haven't tried a RAIM check before - will have to do that and see what that bug looks like.

 

BTW, very much looking forward to seeing what the new products have to offer.  Not that I've ever had serious issues with the existing units other than this particular annoyance.  In fact, I'm rather curious what "better" is going to look like (other than things like support for FSX SE and P3D which are certainly not inconsequential) in units that already perform so well.

 

Scott

[ryanbatc 12,775]

I never had this same issue but I had the issue where the GNS530W would slowly lose AP steering.  What I mean is that the autopilot on my aircraft (or the CDI needle on my HSI) would show off course, and the AP would never correct.  This is all while on GPSS mode.  I think over time (as in a long flight, or multiple flights in the sim, and/or switching between VLOC and GPSS) the unit loses it's connection or something.  It seems similar to what you describe.  But in all honestly I haven't flown FSX in a long long time.

[tttocs 301]

Hi Ryan,

 

Sounds like the issue you've seen is a different one.  I have no trouble with the units driving the AP through extremely long flights with solid accuracy.  My issue is almost as if the units seem to lose satellite coverage momentarily and repeatedly for a minute or two - though if I flip to the satellite strength display all appears to be well.  After these brief clusters of losses, everything goes back to normal.

 

If I'm flying with the AP, I make a habit of keeping the AP HDG bug set to the current course so that I can quickly flip over to HDG mode while the GPS unit has its little fit.  As I mentioned, the only time this is anything more than an inconvenience is if I'm flying a GPS approach when it occurs.  That hasn't happened often, but it has happened.

 

Scott

[Bert Pieke 7,584]

Good piloting habit!