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Thread: Temporary loss of ADS-B

  1. #1

    Temporary loss of ADS-B

    Hi AFS,

    I'm not entirely sure where to start, with AFS or NavWorx, but I'll start here because of the forum and a few other quirks I've noticed over the last couple of months.

    Back in November 2014, I added a NavWorx ADS-600B UAT to my list of avionics. In addition to the RS-232 lines between the EE-4500 (8.8.29), GTX-327, and UAT (4.0.3), I connected the 'UAT Error' pin to one of the EFIS's switch inputs to alert of any UAT errors. The setup has been working very well since then.

    This afternoon, my Wife and I took a short flight to a local airport. During climb out, I noticed that there wasn't any traffic despite being close to Class C airspace and a very nice day. Even though there wasn't a 'UAT Error' annc, I was still a blit suspicious that things were not working as expected. I soon discovered that I could not retrieve any METAR information from local airports thus confirming my suspiciouns. I did capture this from the 'ABOUT' page which looks to indicate that the EFIS was not receiving any UAT data:

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    I rebooted the EFIS in-flight w/no improvement.

    I've no practical way to reboot just the UAT short of power-cycling the entire panel - which I didn't do.

    About 3/4 of the way to our destination (about 15 mins after the in-flight reboot) the A/P (AFS Pilot) starting pitching +/- 200 feet in a very slow oscilation. The A/P switch was selected to accept commands from the EFIS. From that point on, I hand flew the rest of the way. I don't recall ever experiencing this A/P behaviour so I don't know if the in-flight reboot had any contributing cause to this.

    During lunch, I looked to see if there were any, or if I had missed, any NOTAMs about ADS-B being OTS. I didn't find any.

    As we were headed back after eating lunch, the UAT and A/P were working as normal - I could see targets, retrieve METARS, and the A/P behaved as it usually does. Here's the 'ABOUT' page:

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    Some other quirks: I've had audio annc either go mute or change in volume during playback. For example, on one flight, I was practicing stalls and the 'ANGLE-ANGLE-PUSH-PUSH' sounded a couple of times then nothing. On my return back to my home base, I saw the 'MINIMUMS' visual alert but no audio. While on the ground and the engine stopped, I found the audio alert playbacks and I could hear them faintly. I increased the EFIS's volume from 75 to 80 and things were back to normal but just a bit louder. I returned the setting back to 75 and things sounded normal. I left the setting at 75.

    So, any ideas on where I should start looking? Should this happen again, what can I do to help out?

    I know this is NavWorx centric but I'll ask anyway: I know I can see realtime data/logs via the UAT's console port, but does the UAT have a means to d/l logs from the past couple of hours?

    Thank you,
    /\/elson

  2. #2
    Hi dnelson,
    This thread is of interest because l have a 4500 and Navworx as well. Once in a while the ADSB does not seem to work. I do not have the indicator light connected because I have read on VAF that some were having trouble with the light working properly. Do you have it connected and does it function as it should? Is this the wire (pin 14) you connected to the 4500? Once in a while when it is not displaying I will recycle the Navworx and it comes up soon after, I think it is just a coincidence. One day I hope to figure this out, maybe having a laptop connected to the Navworx. It could just be the FAA system is goofy at times? I hope to learn from this thread.
    My suggestion is if you have a CB installed make it a push pull type so you can try a reboot on the ADSB if you want. Please follow up with whatever info you find out. Thanks, Larry

  3. #3
    Nelson,

    After spending many months troubleshooting a similiar issue, I can truly relate to your frustrations. I can share some troubleshooting techniques.

    Monitor the OSHIP count. If the counter is increasing, you at least have sucessfull communications between the Navworx unit and the EFIS.

    Unfortunately, the only real way to validate the output of the Navworx unit is to fly with a laptop on the maintenance port. The is a real PITA unless you have a second person to handle this task. You can see the status of just about everything from the laptop.

    It turned out my issue was neither due to the EFIS or the Navworx, but to an intermittent power issue. I wouldn't have believed it until I had the laptop in the cabin. In all fairness, Rob advised to look at the power early on. Also Ken's ADSB updates also helped with the display, but wasn't the root cause of any of my issues.

    bob
    Bob Leffler
    N410BL - RV10 - Flying
    http://mykitlog.com/rleffler

  4. #4
    Hi Larry,

    As for the 'UAT Error' annc, yes, it's P1_14 (pin #14 of the P1 connector) from the UAT to Input_#3 (pin #8 of the 4500's main harness). It will annc (visually and audibly) breifly during startup which does not supprise me. Now that I'm thinking about it, I've had it annc very briefly in flight on two occasions. By the time I bring my eyes into the cockpit to see what's generating the audible alert, it resolves itself and things continue to work normally. This is another reason I'd like to know if there are history log files availale to review. As will new systems, it takes time to learn how they work or what their "personalities" are. I'm still in a learing phase so it's difficult dicern "normal" from "not so normal".

    Unfortunately, the UAT is fused. When I designed/built the panel years ago, I allocated space for pullable breakers for a key number of items (which have already been used). It did cross my mind the other day that things, particularly electronics, that don't have an internal on/off switch should have an external means to control them. Live and learn. I'll have to see how things play out before I consider this a "fix". I use quotes because I consider this a band-aid rather than identifiying the root cause.

    > Once in a while when it is not displaying I will recycle the Navworx and it comes up soon after, I think it is just a coincidence.

    I'm curious why you think it's just coincidence - could you pls elaborate? What firmwre version is your UAT using? Version 4.0.3 looks to be latest from NavWorx.

    I'm going to add an item to my preflight checklist to check the 'ABOUT' page to ensure that I'm receiving data from the UAT. Questions for AFS/NavWorx: If I'm on the ground in the middle of the boonies with zero ADS-B reception but with a properly functioning unit, will the EFIS' ABOUT page still show signs of data from the UAT? Should this problem reoccur while on the ground, what can I do to help out?

    /\/elson

  5. #5
    Hi Bob,

    > Monitor the OSHIP count. If the counter is increasing, you at least have sucessfull communications between the Navworx unit and the EFIS.

    Great - Thx for that.

    > Unfortunately, the only real way to validate the output of the Navworx unit is to fly with a laptop on the maintenance port. The is a real PITA unless you have a second person to handle this task. You can see the status of just about everything rom the laptop.

    Did you have to use their 'UAT Console' program to monitor this? I've not looked at the serial port in "raw" mode to see what, if anything, is being sent out. If that's the case, it'd be easy to setup a serial logger.

    > It turned out my issue was neither due to the EFIS or the Navworx, but to an intermittent power issue. I wouldn't have believed it until I had the laptop in the cabin.

    Interesting. Would you mind describing your symptoms?

    /\/elson

  6. #6
    Email Ken@Advanced-Flight-Systems.com for the latest software to test with.
    Rob Hickman
    Advanced Flight Systems Inc.

  7. #7
    Quote Originally Posted by dnelson View Post
    Did you have to use their 'UAT Console' program to monitor this? I've not looked at the serial port in "raw" mode to see what, if anything, is being sent out. If that's the case, it'd be easy to setup a serial logger.
    Yes, version 4.03. I did upgrade my unit to the TSO version after OSH. The three items on the status page with tell you the overall health. You can also look at the data coming too. It's been awhile and I don't recall all the options off the top my head.

    Quote Originally Posted by dnelson View Post
    > It turned out my issue was neither due to the EFIS or the Navworx, but to an intermittent power issue. I wouldn't have believed it until I had the laptop in the cabin.

    Interesting. Would you mind describing your symptoms?

    /\/elson
    My symptoms were that it worked every other flight almost religiously, then would work for the next three of four flights, then go back to the every other flight mode. It was never intermittent during the flight, which is why I didn't suspect a power issue initially. It turned out to be a power problem, although I haven't determined the root cause yet. I put a quick fix by running a new power circuit. The old circuit will be examined when I do my conditional here shortly. What alerted me was a dead maintenance port when I was having issues. I had no way of discovering this in the air other than having the laptop hooked up in flight.
    Bob Leffler
    N410BL - RV10 - Flying
    http://mykitlog.com/rleffler

  8. #8
    Hi Rob - Email sent.

    Hi Bob - Wow, that's one for the troubleshooting books. When I was configuring the UAT back in November, the 'UAT Console' program would just up and quit if I let it sit for awhile (10-30 secs?). I would then restart the app, re-select the COM port and all my settings would still be Ok. At the time, I chalked it up to the app. Did you encounter this, too? Just wondering if this was a hint I should have paid more attention to.

    Thank you,
    /\/elson

  9. #9
    Quote Originally Posted by dnelson View Post
    Hi Bob - Wow, that's one for the troubleshooting books. When I was configuring the UAT back in November, the 'UAT Console' program would just up and quit if I let it sit for awhile (10-30 secs?). I would then restart the app, re-select the COM port and all my settings would still be Ok. At the time, I chalked it up to the app. Did you encounter this, too? Just wondering if this was a hint I should have paid more attention to.

    Thank you,
    /\/elson
    No, that isn't normal. I've had the UAT console open and running for periods longer than an hour. I would give Bill a call to help troubleshoot the application issue. The demo mode will time out, but the console still runs. With that said, I'm also still running XP. The laptop at the airport can't run anything more current.

    bob
    Bob Leffler
    N410BL - RV10 - Flying
    http://mykitlog.com/rleffler

  10. #10

    Follow-up Results

    To the serial connectivity issues, I've received some updated firmware from Ken@AFS to try out. Need to load/test and provide any feedback.

    To the brief 'UAT Error' alerts, this is a known issue that will be fixed in UAT firmware 4.0.5 from NavWorx. I'm keeping an eye on NavWorx's web page: http://www.navworx.com/Downloadable-Documents.php

    To the UAT Console program suddenly quitting, likely a USB/RS-232 issue. Not a concern.

    /\/elson

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