GPS Fault & loss of data input signals
Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=478
Printed Date: 30 Apr 2024 at 5:00am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: GPS Fault & loss of data input signals
Posted By: oskrypuch
Subject: GPS Fault & loss of data input signals
Date Posted: 06 Dec 2014 at 8:04pm
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Well, the picture below shows it - GPS Fault - No position Flew for about an hour on Saturday, then landed, all good, and loving the unit. On startup about 10 mins later, NO GPS signal, even after several minutes. I tried power cycling, pushing in on the GPS, restarting, etc. No GO. Exactly the same. If you continued to stare at the GPS status display, it would occasionally flicker one empty bar, but that is it. I flew home VFR. GPS stayed faulted. In addition, that forced the transponder into GND mode, so had to power off the GPS to allow the MODE switch to force it to ALT. I am hoping it is just the antenna connection worked loose, or something equally simple. But unfortunately I lose out on this weekend's flying. Was so looking forward to getting some time in with the unit. So it goes. * Orest  |
Replies:
Posted By: MysticCobra
Date Posted: 06 Dec 2014 at 10:19pm
| Bummer, Orest. Hope the solution is simple and quick, but it's too bad that you'll lose out on the weekend flying regardless. |
Posted By: tony
Date Posted: 07 Dec 2014 at 8:32am
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Orest, that sucks. It would be nice if your shop could throw a 530 in the tray to see if it has the same problem. That would help figure out quickly if its a IFD 540 problem or an installation problem. So you had to power down the IFD540 to get the transponder to work in modes A and C? I assume you are using the squat switch signal out of 540? I planned on using the same signal. That got me reading the 340 installation manual. It says that if you set the unit up to use an external squat switch; the pilot selectable states for mode are when in the air: ALT-ON-SBY and when on the ground: GND-SBY. (page 27) I don't know if I like that. Steve: welcome back!!! I think we should think about the failure modes of the system design: Perhaps the logic in the 540 could change so that the default state is in the air. Sounds like you have the default state as a high (ground) and when the GPS is working and figures out that its moving asserts a logic low (air). This is backwards. The signal should default to in the air (safe state) and is asserted when the 540 thinks its on the ground. [I know that might cause the 340 when the aircraft is powering up to transmit airstuff for a couple of seconds] or what you can do is change the logic in the 340 and allow the pilot to decide what mode he/she wants to be in when using he mode function regardless of what the air ground switch is saying. That's the change I would make. I know making changes at this point in the 340 is costly and difficult since its your vendor. or we could take care of it operationally like Orest did and that's power down the 540. I don't like this one. |
Posted By: AviJake
Date Posted: 07 Dec 2014 at 9:23am
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Yeah, I need to check that one out. The default state for the IFD540, given no GPS input, is AIR. Now we need to figure out why that didn't propagate. ------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: tony
Date Posted: 07 Dec 2014 at 11:03am
| Steve.... Welcome back!!! We missed you!! |
Posted By: oskrypuch
Date Posted: 07 Dec 2014 at 11:44am
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I pulled the plane out today (Sunday), and had another look.
Happily the error is consistent (and developing),
not so happy that there is a problem. This appears to be an install
issue, rather than a problem with the unit. Unit may not be properly seated. The GPS is still showing no bars, but now, also, there was no connection on the 429 bus, no connection to the lightning sensor, and the transponder was working normally (so no "errant" ground state ON message sent to the transponder any more) The traffic and lightning was working fine on
the ASPEN. More information: Apparently, during the install it originally locked into a signal in the shop first
thing in the morning, but then faulted much the same. They had had
trouble inserting the unit flush into the tray, and the installer was
wondering if that was the issue, resulting in the antenna not
contacting. Apparently Piper rails are tight, and the shop used some rivnuts which take up a bit more space as well. Add in thermal expansion and/or cooling to ambient, and that might explain it.  * Orest |
Posted By: oskrypuch
Date Posted: 07 Dec 2014 at 1:36pm
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The avionics shop owner just responded to my email, today, Sunday! It will be going back in tomorrow (Monday), and it "will be fixed." I'll follow up here.
* Orest |
Posted By: tony
Date Posted: 07 Dec 2014 at 3:14pm
| Steve, I'd be interested in what you find out with the air/ground logic. Otherwise I think I'd going to add a DPST switch. |
Posted By: AviJake
Date Posted: 07 Dec 2014 at 7:18pm
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Roger. ------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: brou0040
Date Posted: 07 Dec 2014 at 8:09pm
| Any news on the update USB covers that will close easier? |
Posted By: AviJake
Date Posted: 07 Dec 2014 at 8:21pm
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I'll check on Monday but it's queued up behind the IFD440 hardware qual. Same guys working both. ------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: oskrypuch
Date Posted: 08 Dec 2014 at 8:15pm
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Well, bad news. It does NOT appear to be a simple install issue. Unbenounced to me , the tray fit issue was solved, it was actually that the back of the unit was not sliding into the TAWS socket (before it was pinned), which prevented it from sliding fully back and seating. Sadly, the data problems continue. Intermittently the GPS signal is lost, together with the 429 bus input (ASPEN), the lightning sensor input, and/or the traffic input. It is never exactly the same combination. It is interesting that all of these inputs are on one connector, the P1001 connector, which is right beside the coaxial GPS antenna input. Could it really just be a co-incidence? The shop could not generate (or resolve) the problem externally, the "jiggle the cords" sort of thing. They spent the morning on it. They called Avidyne, who requested a data dump. It was sent. Avidyne seems to be focused on solving this. It could very well be some sort of in-box connector issue. It could even be that there is some bowing of the connector, but the case is pretty heavy duty. Sadly I'm stuck for now. The intermittency of the issue is the nightmare. And, I can't very well fly with it now, it cannot be relied on in its current state.. Just my bad luck I guess. Will keep all updated. * Orest |
Posted By: oskrypuch
Date Posted: 09 Dec 2014 at 7:55pm
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The good news ... The errant unit was pulled, and another IFD540 was slipped in. All the errors stopped, at least for the five hours it was installed in the shop. Pretty good indication, the next few days will make it a sure thing. So likely, it was just a bad production unit, not an install issue. Avidyne has issued an RMA and will be shipping a new replacement unit for an exchange. The shop will let me use the swapped in unit until then. ALL GOOD ... I'm back in the AIR! * Orest |
Posted By: pburger
Date Posted: 09 Dec 2014 at 8:06pm
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FWIW, when I had my G-brand GNC-300XL put in back in 2003, it took two swap-outs before I got one that worked. The third time was the charm. Let's hope the second time is the charm in this case!!
|
Posted By: MysticCobra
Date Posted: 09 Dec 2014 at 9:27pm
| Well, since he's just using a loaner until his permanent replacement comes in, it's still appropriate to hope for the third time to be the charm. :-) |
Posted By: oskrypuch
Date Posted: 19 Feb 2015 at 6:20pm
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This issue has now been definitively solved with the 10.0.3.0 firmware update. * Orest |