ARINC-429 dropouts are still a problem that has not been addressed - or even acknowledged.

[airguy]

They have been occurring with regularity to a large number of Skyview users, myself included. Today flying home from the Reno Air Races I had a number of minor dropouts and one that lasted long enough that the autopilot kicked off GPSS mode to track mode.

Here's a screenshot of one of the events, I was on autopilot at 15,000 feet with the 430W feeding the ARINC, and you can see that the 430W data has disappeared from the screen. This lasted maybe a second and a half and it came back - but it did it enough times during the flight that I was ready to capture a screen grab and got one.

Shortly after that I had another one that lasted long enough to kick off the GPSS and drop down to Track mode - and I got a Dynon Diagnostic File captured right after that, so there should be a good evidence trail of what happened. I can't include that here on this message as it's too large - I'll upload it to the Dynon site.

How about it Dynon - will you finally admit there is a problem here and at least acknowledge what we already know - that it exists? And maybe even that you are working on it?

 

[Dynon]

Sorry to hear you're still experiencing issues with this. We thought we fixed ARINC drop outs quite a while ago. It was not super conclusive, as it's always been hard to reproduce, and pretty rare in the field, and so this has been a tough issue to chase. After we did the fix, people having the issue mostly seemed to be fixed. We can look at your data and see if there is something else going on though. Please get in touch with our support team directly so we can try to see what you're seeing.

 

[Flying_Monkey]

They have been occurring with regularity to a large number of Skyview users, myself included. Today flying home from the Reno Air Races I had a number of minor dropouts and one that lasted long enough that the autopilot kicked off GPSS mode to track mode.

Here's a screenshot of one of the events, I was on autopilot at 15,000 feet with the 430W feeding the ARINC, and you can see that the 430W data has disappeared from the screen. This lasted maybe a second and a half and it came back - but it did it enough times during the flight that I was ready to capture a screen grab and got one.

View attachment 3621

Shortly after that I had another one that lasted long enough to kick off the GPSS and drop down to Track mode - and I got a Dynon Diagnostic File captured right after that, so there should be a good evidence trail of what happened. I can't include that here on this message as it's too large - I'll upload it to the Dynon site.

How about it Dynon - will you finally admit there is a problem here and at least acknowledge what we already know - that it exists? And maybe even that you are working on it?

154KTS TAS at 7gph! What magical airplane is this!?

 

[DBRV10]

Here is a question for you.....and you may have to think back to what frequency the GTN/GNS/IFD was tuned to at the time. What were you tuned to on your GPS/COM.

I think I might have the answer, which may start a long thread of things.

 

[airguy]

Here is a question for you.....and you may have to think back to what frequency the GTN/GNS/IFD was tuned to at the time. What were you tuned to on your GPS/COM.

I think I might have the answer, which may start a long thread of things.

At that point in time, I was talking to Salt Lake Center on 125.575 through my 430W. What is your theory? The dropouts are not associated with transmitting from the unit, the vast majority of them occur during cruise without transmissions.

 

[Animosity2k]

154KTS TAS at 7gph! What magical airplane is this!?

Not sure what he's flying but I fly a Flight Design CTLS and get about 125-135 kts burning 3.5gph

 

[airguy]

This is an RV9A, I normally cruise in the 14k-17k altitudes and average 22 nautical miles per gallon there, with a 1500nm range. Notice in the bottom right of the picture the "runtime" shows current flight time at 2 hours 24 minutes, and the range to empty exceeds 1000 miles up there with the fuel left in the tanks.

 

[Raymo]

154KTS TAS at 7gph! What magical airplane is this!?

Airguy and I both have RVs. Mine is a -7A; I cruise at 155-160 knots on 8 GPH but working on incremental improvements to the engine and aerodynamics to go even faster. VNE is 200 knots.

 

[DBRV10]

At that point in time, I was talking to Salt Lake Center on 125.575 through my 430W. What is your theory? The dropouts are not associated with transmitting from the unit, the vast majority of them occur during cruise without transmissions.

So my wild guess was something like a fellow down here has been suffering. Whenever he was tuned to (not transmitting) 121.20MHZ satellite coverage would falter.

The frequencies Garmin know to be an issue are 121.15 MHz 131.22 MHz 121.17 MHz 131.25 MHz 121.20 MHz 131.27 MHz 121.22 MHz 131.30 MHz 121.25 MHz 131.32 MHz 131.20 MHz 131.35 MHz, as well as 121.185 MHz 130.285 MHz 121.190 MHz 131.290 MHz.

So next questions are;
1. Do you have a fixed ELT?
2. How long is the Coax to the GPS antenna and is it RG400.
3. Where is the GPS antenna mounted and what distances are there between it and any other devices. Please detail what they are and distance.
4. Have you removed and re-racked the 430W? As stupid as it sounds, this is often an issue. Check connectors for any evidence of corrosion or anything similar.

 

[airguy]

All those points would be indicative of a problem with the 430W, which has never shown a fault. I've never lost satellite lock, never had a RAIM warning, never had it give a hint of trouble in the just-over-500 hours I've had in the panel. I have no evidence to indicate the problem is within the 430W, and particularly not the GPS-reception side of the 430W.

I do have an ELT, it's not transmitting - gets frequently tested, and the antenna is behind the cockpit while the GPS antennae are forward. My GPS antenna is about 6 horizontal feet from the 430W and is RG400. The Garmin GPS antenna is mounted on a shelf under the cowling ahead of the firewall with my Dynon 2020 GPS and Garmin G5 remote antenna - but again it's apparent to me that the problem does not exist on the GPS reception side. For the last point, not in the last 300 hours, no.

 

[swatson999]

I agree...the problem is not with the 430W. And as far as frequency interference goes, there's a simple test procedure in the Garmin install manual (these frequencies are the odd harmonics of the GPS frequency which can cause destructive interference). I've had it happen a couple of times, albeit not recently, and the symptoms wee identical. AP switched modes, etc. I even *saw* the loss of the GPS course line on the Dynon display for a second or two.

It has to be (famous last words) in the ARINC box...something loses sync for a bit until the communications sync back up. Buffer overflow or something like that on the comm port, likely.

Oh, and FWIW, I have both the GPS-2020 and the Garmin GPS antenna on a shelf just foreward of the firewall under the cowling, never an issue with either.

 

[DBRV10]

All those points would be indicative of a problem with the 430W, which has never shown a fault. I've never lost satellite lock, never had a RAIM warning, never had it give a hint of trouble in the just-over-500 hours I've had in the panel. I have no evidence to indicate the problem is within the 430W, and particularly not the GPS-reception side of the 430W.

I do have an ELT, it's not transmitting - gets frequently tested, and the antenna is behind the cockpit while the GPS antennae are forward. My GPS antenna is about 6 horizontal feet from the 430W and is RG400. The Garmin GPS antenna is mounted on a shelf under the cowling ahead of the firewall with my Dynon 2020 GPS and Garmin G5 remote antenna - but again it's apparent to me that the problem does not exist on the GPS reception side. For the last point, not in the last 300 hours, no.

NO.......all those points are not indicative of a fault with the 430W.

They are things you need to be aware in installations.

I have seen the odd flicker of the HSI over time in the years past but I must say since Dynon hopefully fixed it, I have not seen it so far.

I have NEVER had the Skyview drop the GPS and default to track/heading mode.

I do have 1700+ hours of trouble free GPS/Skyview on my own plane and more on others. I can tell you that in every case where there is more than 2 feet separation and 13+ feet of Coax, there are zero problems. I can also tell you that several RV's with under cowl, side by side installations do have problems from time to time.

Make f that what you will. These GPS antenna's are power and emit things that might interfere in some installations.

6 feet......is that 6 feet of Coax? Again Garmin would say that is not long enough.

Please try re-racking the unit, that has solved many a 530/430 issue in the past, also, you are in a WAAS area, make sure all other SBAS sources are turned off.

 

[swatson999]

I'm just not convinced that this is a 430 problem or issue. I've had the course guidance loss on two occasions, and during the brief losses, the 430W showed no change in status. Further, if it was an *antenna* problem, doesn't the 430W go into Dead Reckoning mode for a time (and announce this on the screen)?

So device A is chugging along, fat, dumb and happy...device B stops showing data from device A. The two are connected by device C. Seems to me the problem lies in one of 3 places: the comm port on the sending device, the intermediate device, or the receiving device. Given the hundreds of thousands of installations of 430s which communicate with a myriad of other vendors' displays/PFDs, my money remains on the ARINC box.

And yes, I have the big coil of coax to meet minimum cable length to the antenna...

 

[kurtfly]

I also am still seeing occasional ARINC dropouts with my GNS430W to Skyview Touch. Before I upgraded to Skyview I had a Sandel SN3300 EFIS. Never had a single drop in 15 years. I currently see these on occasion. They are most noticeable when on a long trip where I am on autopilot and the dropout lasts long enough to cause autopilot to change to track mode.
I am in the middle of changing out my GNS430W for the IFD540. I will report back if I see any dropouts. This change will use all the same wiring, only moving 430W connectors to new, larger tray.

 

[kellym]

All those points would be indicative of a problem with the 430W, which has never shown a fault. I've never lost satellite lock, never had a RAIM warning, never had it give a hint of trouble in the just-over-500 hours I've had in the panel. I have no evidence to indicate the problem is within the 430W, and particularly not the GPS-reception side of the 430W.

I do have an ELT, it's not transmitting - gets frequently tested, and the antenna is behind the cockpit while the GPS antennae are forward. My GPS antenna is about 6 horizontal feet from the 430W and is RG400. The Garmin GPS antenna is mounted on a shelf under the cowling ahead of the firewall with my Dynon 2020 GPS and Garmin G5 remote antenna - but again it's apparent to me that the problem does not exist on the GPS reception side. For the last point, not in the last 300 hours, no.

I agree that your 430W is not part of the problem. The poster is correct that ELTs can and do create problems without transmitting at all. However, most of those issues are caused by a strong VHF transmitter nearby, usually FM or TV, exciting the ELT oscillator.
Clearly your problem is in the ARINC communications between Dynon and 430. I have no idea whether that might be in the ARINC box, the firmware, or the connections between 430, ARINC box or Dynon screen

 

[airguy]

I got a note from Dynon Support telling me that per the logs I sent, it appears the data is reaching the Skyview system and something is occurring within the Skyview hardware. They will prepare a new software version with extended logging capability for me to fly and try to pinpoint the problem.

This supports my contention, and the evidence I'm seeing, that the 430W (and its installation - thank you David Brown for immediately assuming I am unable to interpret an installation manual) is not the problem.

 

[DBRV10]

I got a note from Dynon Support telling me that per the logs I sent, it appears the data is reaching the Skyview system and something is occurring within the Skyview hardware. They will prepare a new software version with extended logging capability for me to fly and try to pinpoint the problem.

This supports my contention, and the evidence I'm seeing, that the 430W (and its installation - thank you David Brown for immediately assuming I am unable to interpret an installation manual) is not the problem.

I assume nothing. When you deal with lots of people and their problems you MUST fault find with the common problems. If I did not ask the questions how could you expect anyone to assume things are 100%..........You never specified all these things in your opening post did you?

I hope you solve your problem and report back for others to benefit from the experience.

 

[kurtfly]

I have now been flying with the IFD540 and see the dropouts. Same as I did on the GNS430W. again only a momentary dropout where the magenta course indicator blanks out for a couple seconds. This makes me think the problem is with Skyview and/or the ARINC box. I have seen this with both the Garmin GNS430W and now the IFD540.

 

[airguy]

And I'm still waiting on the promised higher-sensitivity software build to find the bug.

 

[Jrskygod]

ditto what others are experiencing. I occasionally get a drop out on my IFD 440 and had the same situation several times with the Garmin 430w that I originally had. Sometimes it will drop off the autopilot sometimes not. The HSI will blink and the course line will go away for a second sometimes less. Always gets your attention when on an approach. Other than checking connections etc. it has been difficult to find the cause especially since it happens infrequently.