NAVSRC LOST

[JR]

Where did we end up with this problem?
I have D180, single servo, 296, using 5.3? (no pitch servo so havent updated to 5.4)
When using NAV mode from G296, Around every 30 min states NAV SRC LOST and reverts to TRK mode
I just go and reselect NAV and runs again fine for 30-50 min

 

[dynonsupport]

I don't have the full list of bug fixes in front of me, but I do believe that 5.4 improves this behavior somewhat, but we're not sure we have it fully solved yet. Can you update to 5.4 and report back?

 

[JR]

yep

 

[Brantel]

5.4 does make it much better but it is not fully resolved. It still happens....

 

[dynonsupport]

How often do you see dropouts with 5.4?

 

[redmark]

I think I'm seeing the same problem...

D-180 & AP are reporting loss of the GPS NAV source (Note: the Garmin
496 didn't report a loss in the satellites signal(s)). At this time I
only have 33 hr. on the RV-12 and only 3.5 with the AP installed but I
can make the following observations.

1. The Garmin did NOT report signal loss
2. This seems to be related to the AP & NAV function as I only see the
warning during this operational mode.
3. I probably have 20 hr. using the D-180 & HSI for navigation and
I've never received a warning about loosing the GPS source but I
guess the software could be taking a different code path in the D180 or the AP is triggering the warning?
4. I know of two other RV-12 owners who has seen this issue too.
5. I've recorded each time I've received this warning based on the D180's trip timer...

I was just wondering if maybe there was some setting to delay this
warning or retry the connection before reporting. The AP automatically
flips into TRK mode and pushing the NAV button connects it back-up
to the GPS immediately.

One more new issue is the D180 backup battery... it's always dead now. I've let it charge but each time I return to airport the backup battery is dead. Van's does not provide me a schematic but I'm wonder if the AP or Servos could be draining the backup battery? The D180 is only 5 months old.

 

[JR]

Re back up battery, I had a similar problem, it turns out the plug connecting it to D180 wasnt making good contact.
It would appear to be charged in flight then instantly go to zero volts when D180 main power turned off.
I slightly bent pins in plug and has been perfect since.

 

[dynonsupport]

redmark - are you running firmware version 5.4?

 

[redmark]

Correct, all devices are at the 5.4 levels.

 

[DBRV10]

One of the RV8's that I fitted the AP to last year is reporting the odd nav drop out on a Garmin hand held also running 5.4.

DB

 

[redmark]

Which data line should I examine to fix the lost NAV issue? On a 4.5 hr trip yesterday in my RV-12 (2 segments about 2 1/4 hr each) the D-180 /w the auto pilot dropped the NAV function and reverted to TRK function 26 times. Pushing the NAV button connect it back each time.

The setup is an RV-12, D-180 & Garmin 496.

Thanks,
-Ron

 

[Brantel]

The weird thing is with this bug is that it seems totally random.

I have had flights where it would do it every few minutes, I have had others where it never did it. I have had it happen 2 seconds after I enable the AP and I have had it wait 30 minutes.

It also does not seem to matter what NMEA GPS you have as I have seen it with two different ones first hand.

5.4 did reduce it somewhat.

 

[dynonsupport]

Unfortunately, it's not as simple as a bad connection. Though that could cause the dropout, it's not likely. We've been struggling to detect and gracefully recover from when the NMEA data goes momentarily bad, but we still don't have it completely solved. It's on our list to keep attacking in future firmware releases.

 

[BigJohn]

RV-12 120176 N37JP D180 G496 AP74 Version 5.4

Flew two cross-country legs today, about an hour each. Had the above described symptom about twice in each direction. Seems random. Actully glad to see it is a known issue and not a problem with my setup!

 

[jaba-who]

I have started getting the same problem  with a previously functioning well Version 5.4. Same scenario - loss of nav source but instantly returns by pressing the nav button on the AP74.

I also have had two episodes of sudden  roll (1 each way) so far only while in nav mode.


My loss of nav source are also quite random and on some flights happen every few minutes and some only every half hour or so.

I previously had a problem with complete loss of nav but that was cured with cleaning up contacts. I assumed this new problem was from same cause but reading this thread, maybe not.

 

[BigJohn]

Drop-outs still happening.....

Just an update. Flew two long cross-country flights last week. Four legs, over two hours each. Multiple random failures. This is not dangerous, just annoying.

I encourage you guys at Dynon to keep working on a fix for the next release.

John - RV-12, D180, AP74, G496

 

[redmark]

John,

I see this all the time in my RV-12 too but I don't see other -12 owners squawking about it... I don't know if it's just not an issue with them or if there is just a low number of -12s with the autopilot option. Or something in my installation.

-Ron

 

[jakej]

DS

Just a wild thought here - maybe these guys could install one of those 'filter' type dsub connectors onto the AP74 or use shielded wire (grounded at both ends) as maybethe issue could be EMI ?? worth a try ?

Jake J

 

[dynonsupport]

We don't think it's a signal issue that wiring changes would handle, but rather actual bad data coming across for moments.. So no wiring changes will yield results (for this particular problem), and we think we can do more with further software improvements.

 

[BigJohn]

Support,

Thanks for the reply. Any idea when we might see something like a "maintenance release" for fixes such as this?