ADS-B In Offline (for just a moment)

[swatson999]

What might cause the ADS-B IN to alert with a "Caution" message "ADS-B In Offline", but only for a second or three, then it's okay? This has happened on VERY rare occasions, maybe once in 50 hours, and I'm quite sure the wiring is okay.

Is it a protocol thing, perhaps the messages getting out of sync for just a cycle or two, then the comm syncing back up?

 

[swatson999]

Bumping this up...had this happen again today. ADS-B In went offline for just a couple of seconds, then all was well for the duration of the approximately 1 hour flight.

Any ideas here? I'm fairly confident this is *not* a wiring problem....

 

[Dynon]

It's most likely either mechanical (connection) or something up with the unit itself. Anecdotally, the SV-ADSB-470 is very very reliable and I'm not sure we've ever seen one fail in this way. We're happy to take a look at the module if you'd like. Give our support team a call at 425-402-0433 or at support at dynonavionics dot com. One place to look, besides the wiring, is at the actual Dsub pins. are they all making good contact? Are any of the pins in the male connector recessed and maybe have the ability to have intermittent contact?

 

[swatson999]

I'll give them a call, and try to grab a diagnostic file as well. I can send it in along with the EMS for that filter/fix for little spikes in EGT/CHT when transmitting at the same time as I send the display in for upgrade to touchscreen...which is going to be *really really soon now*, right?

I've been down this path before with suspected wiring, and although nothing is certain in life, I doubt that it's a wiring problem. Every one of my wires were properly crimped, using a DMC "little blue" crimper and positioner, pull tested, properely inserted into the connectors, checked for proper insertion, etc. Stripping/crimping/cabling/etc. was done to the NASA wiring spec.

Bad wiring, in my experience, doesn't show up once in a hundred hours or so, for one or two seconds, and then go away for another 50 hours, etc. This smells more like a loss of sync between the two boxes' communications (UARTs?) that then re-sync after a second or two.

 

[krw5927]

You're not going crazy, Steve. I've had the same issue occur exactly twice. I REALLY don't like hearing "caution" in level cruise.

Never happened before software version 12.

 

[jakej]

Bad wiring, in my experience, doesn't show up once in a hundred hours or so, for one or two seconds, and then go away for another 50 hours, etc.  This smells more like a loss of sync between the two boxes' communications (UARTs?) that then re-sync after a second or two.

Steve

You are quite correct however what Dynon is saying that although you know the wiring has been done properly with the good tooling the dsub connection 'may' be at fault.

I've raised a pirep about this before - although, in my case, the pin/socket clicked in it also came out very easily so I trashed the dsub.  After a couple of instances of this I now also do a gentle pull test to confirm they are holding 

Jake J

 

[Dynon]

We'd love to get a diagnostic file that contains the event. One note here though: you need to get it within about an hour or so of when it happened, else it will have been overwritten by new data.

 

[swatson999]

Bad wiring, in my experience, doesn't show up once in a hundred hours or so, for one or two seconds, and then go away for another 50 hours, etc.  This smells more like a loss of sync between the two boxes' communications (UARTs?) that then re-sync after a second or two.

Steve

You are quite correct however what Dynon is saying that although you know the wiring has been done properly with the good tooling the dsub connection 'may' be at fault.

I've raised a pirep about this before - although, in my case, the pin/socket clicked in it also came out very easily so I trashed the dsub.  After a couple of instances of this I now also do a gentle pull test to confirm they are holding 

Jake J

Yep...I did the same thing...click them into position (using the correct tool), then pull gently to see if it comes back out. Did this because I was aware of the issue of pins not being seated properly by some people, and thus "backing out" of the pin/socket connection.

Dynon...I may still have that data, I'll look and see (IIRC it was on my last flight, so should still be there). I'll check the Alarm Log and compare to my flight logs, and if so, I'll grab the diagnostics and upload it.

 

[swatson999]

We'd love to get a diagnostic file that contains the event. One note here though: you need to get it within about an hour or so of when it happened, else it will have been overwritten by new data.

OK, I got a diagnostic file after another one of these events this weekend. I will upload it to you via the file upload site.

I have the time of occurrence (off by one day due to that bug in the date) in UTC from the Alert log, as well.

It only went off-line for a second or two, then recovered. Grrrr....

 

[swatson999]

OK, another instance. This time, here's the scenario:

Several flights, no issues, over the past week. Worked beautifully. Returned home on Sunday, shut down, put the aircraft in the hangar and then

Today, went to the hangar to prep a bit for removing the SV (wanted to download the config files, etc.). Upon power-up, guess what?

ADS-B In Offline message

Power cycled the EFIS. No joy. Power cycled the entire system. No joy. Removed the fuse from the circuit on which the XPDR and ADS-B are wired, powered up and, as expected, got XPDR FAIL and ADS-B In Offline messages. Replaced fuse. XPDR good, ADS-B still offline.

Decided just for the heck of it to pull the plane out and start it, to see if anything changed (and to show to a buddy to get his assistance troubleshooting). While on the ramp, same thing...ADS-B IN Offline...but then, miraculously, after about a half minute, it *came back*.

This is NOT a case of ADS-B Unavailable...I've had ADS-B IN data while in the hangar since I installed it, and even if it weren't available (which I've seen in flight in areas not covered yet), I don't get a warning message just because of that.

The plane was *immobile* since Sunday, and somehow, it first didn't have ADS-B IN, and then it did.

Has ANYONE else seen this sort of thing? I did get a diagnostic file today and will upload it and notify via email that there is another file which may help solve this.

Again, this smells like a software (or UART) comm problem, but it's getting annoying.

Thanks...

 

[jabarr]

Since installing 12.2, I have seen the ADSB in-offline msg when powering up but it hasn't happened in flight. I never saw the msg before 12.2.
A hangar mate has had a total ADSB system failure with the ADSB in-offline msg being constantly displayed since he installed 12.2. Dynon has his diagnostic files and we are awaiting an answer.

 

[swatson999]

Since installing 12.2, I have seen the ADSB in-offline msg when powering up but it hasn't happened in flight. I never saw the msg before 12.2.

Yep, that's what seems to be happening. Did it again this morning, off-line after power-up, but went away after maybe 1/2 - 1 minute.

SV removed to get shipped back for upgrade to Touch, so we'll see what happens, but I hope Dynon will try to track this down and fix it.

Passengers don't like "Message""s or Warnings or such before the engine even starts

 

[Dynon]

So for those of you that have 12.2 and are now seeing ADS-B Offline: We think there's an issue here that causes ADS-B Offline to be flagged when you don't have a GPS lock. Are any of you seeing it AFTER you're certain that you have a GPS fix? Note that this (probably) doesn't describe issues from before 12.2.

 

[jabarr]

Mine does seem to be only when there is no GPS lock. No offline flag once locked. Never saw it before 12.2.

 

[swatson999]

This would be consistent with what I saw, I think. Inside the hangar, ADS-B offline, pulled the plane out, went away; another flight, initial power-up, ADS-B offline, but quickly went away. So that might be supporting data.

(N.B. I usually get a GPS fix even in the hangar on the SV, never on the Garmin , but I don't recall if perhaps the hangar door was closed which would certainly block GPS signals).

Any ideas what may have caused it prior to 12.2, though?

 

[dynonsupport]

We have verified that the change in 12.2 to cache ADS-B data across power cycles had the unintended consequence of marking the ADS-B device as offline until a valid GPS position is present. There are no observed effect once the GPS has locked on, so once you are taxiing out and through your flight all should be fine.

Thanks for everyone's help, and we'll have this fixed in our next release.

We don't have many comments on this happening before 12.2 so we think if that's happening in a plane it's a unique install situation that we should work on 1:1.

 

[swatson999]

Well, I sent you a diagnostic file from 4/19, so you should have an example of it happening prior to 12.2.

 

[krw5927]

OK I experienced this issue again in flight last night, just prior to entering the pattern to land after about a 45 minute flight. Very doubtful that GPS lock would have been lost. I have not yet installed 12.2.

I'll pull a diagnostic file tonight. How do I get it to Dynon?

 

[dynonsupport]

Drop an email to support AT dynonavionics DOT com and mention this post and that you have a diagnostic file to upload. We'll reply with the upload instructions.

OK I experienced this issue again in flight last night, just prior to entering the pattern to land after about a 45 minute flight.  Very doubtful that GPS lock would have been lost.  I have not yet installed 12.2.

I'll pull a diagnostic file tonight.  How do I get it to Dynon?

 

[swatson999]

Again, this time in flight, once, with NO loss of GPS that I can see (just flying along straight and level, after about 20 minutes or so, and not again the rest of the flight or on a later flight).

Note that this happened to me occasionally *prior* to 12.2, as well.

I'm uploading a diagnostic file which should include the event now (this is the second time I've done this).