Yes, that is the case…. Looks like the old GNS430s were much slower starting up than the "W"s .. and that’s why this got my attention now … If I wait a bit with pressing ENTER the 2nd time and give the AHRS and Stormscope more time … then it doesn’t happen!
Thank you anyway!
Flyer59 wrote:
I have a “Lightning Error” message now before the Stormscope initalizes … goes away though.
Sorry missed this one. Did have that before. Switch of the GNS after you get this message. Switch it back on. Does the message turn come on again? Likely it is not. Then the boot / startup sequence is just so the GNS is slightly faster then the stormscope.
Could we make this a new thread, please?
Of course – anybody and everybody should start a new thread for a new topic 
That statement only says that the DFC90 will process input the same way regardless of input source
It’s still a long way from saying the two buttons do the same thing. They can under certain circumstances. For example, in a certain system configuration, I could demonstrate that my KFC225 flies the same track when in NAV mode (with ARINC429 data) and in HDG mode (if there is a roll steering converter installed, which would be slightly pointless if there is already an ARINC429 connection to the AP).
Simple statements are often really dangerous, but modern avionics are nontrivial.
Flyer59 wrote:
There is no algorithmic difference between the two in the DFC90
The devil is in the details. That statement only says that the DFC90 will process input the same way regardless of input source, but it does not say that the input source is the same!
Edit: I see that Achim wrote essentially the same thing.
In my experience the Avidyne manuals make Garmin look brilliant and that is saying something.
As I said in an earlier post, with the DFC90 there is no reason to use GPSS instead of NAV. While there is a difference, that difference only reduces the utility of GPSS. Achim is the only person I know who makes use of that as a feature!
I would say: you can fly all approaches in NAV mode, but not in GPSS mode.
Achim: so you changed your mind from what you wrote in the Avidyene forum (“no difference”). That’s ok, of course.
Could we make this a new thread, please? I had some questions … see beginning of thread :-)
They are algorithmically identical when the navigation source is GPS (selected on the GNS). That was the scenario this statement applies to I guess. With other autopilots the behavior of GPSS vs NAV with a GPS source is very different between GPSS in essence simulated HDG whereas NAV uses CDI which means overshoot on turn, overcorrect, stabilize, etc. With that distinction in mind the DFC can be confusing and hence the statement that they do the same (for GPS!).
The modes NAV vs GPSS are very different when the navigation source is LOC. That is neither hard to understand nor hard to verify so kind of pointless to argue about it
I would fire him.
He is clueless.
What he is saying is that Avidyne did a totally cynical “our customers are idiots” move of providing two buttons which do the same thing and have different text labels!
i did that, see post above from Avidyne forum!
“You shouldn’t see any difference). GPSS is a legacy holdover for all those pilots who were used to that mode prior to the DFC90. There is no algorithmic difference between the two in the DFC90”
(from an Avidye engineer)
When the GPSS ARINC 429 label is no longer being received after the FAF, the roll steering should command wings level. On a constant wind day, this is sufficient to fool many pilots into letting their autopilot take them to the runway, after all once the wind correction angle is determined, all you need to do is hold that heading
That is the conclusion I came to also. There is nothing else the AP could possibly do (apart from activating the chute) and it’s what a King one does (selects ROL mode).
Also it does the same in HDG mode, upon loss of Heading Valid (or Gyro Valid) signal.
Interestingly the current vertical mode is maintained so you can fly say an ILS without any lateral steering… would probably use the pedals
If somebody can post a quote from COPA, or Avidyne, where somebody is saying the two buttons do the same, I’d very much like to see it.
