compass "shimmy"

[gianmarko]

after upgrading to 5.1 and then to 5.1.1 (not sure there is any relation) the compass shows a funny behaviour. when turning on the EFIS, doesnt matter if with external or internal power, the compass tape shakes badly like there is an alternate magnetic field close to it (there is none, i have tried this with all airplane power off) then the "shimmy" stops when the altitude tape appears but the heading indication is not reliable. in flight sometimes it varies of 40 or 50 degrees, while at times it seems ok.
i will later reload the 5.0 firmware to see if it makes any difference.
wind aloft indication is also badly out, with readings approaching 50% of the cruise speed or more.

 

[gianmarko]

i have reloaded sw 5.0 and shimmy disappear. reloaded 5.1.1 and shimmy is back. i have performed a full recalibration of the compass but it is way out and heading values are way out of wack and pointing north they can over time change by even 180 degrees. not sure it is worth reloading 5.0 and try a recalibration. unless something has failed, with 5.0 heading indications were perfect. now the compass is useless. any idea? maybe the remote compass doesnt like 5.1.1?

 

[gianmarko]

i have rolled back to 5.0 on all devices and compass is back online working flawlessly.

youc an find the 5.0 and 5.1 dumps here
http://gianmarco.dyndns.org/dynon

will add some video and pics when i am on a fast connection.

my airplane is a steel tube structure so for sure a lot of magnetic disturbances, but it seems to affect only 5.1 and 5.1.1

is not the first time a sw update makes my compasses go wild...

Zawinski's Law anyone?

:-/

 

[dynonsupport]

Thanks for the backups. We've heard another report or two that's similar in nature - we'll be looking into it.

 

[jhsalden]

I have updated my D100 to SW version 5.1.1. in order to use my autopilot. I have the same shimmying.

AP works fine.

Joost

 

[dynonsupport]

For anyone having this problem - send pre and post-upgrade backups (zipped) to support@dynonavionics.com with a description of what you're seeing. Before doing that, actually, try recalibrating the heading first (after first looking up your magnetic inclination and total intensity per the installation manual)

 

[gianmarko]

i have a comment about recalibration

of course, i recalibrated the compass after every upgrade. what i have noticed is that, being my a/c a steel tube construction, the headings during calibrations look way out.

calibrating under 5.0, expecially on the north, the heading is way out, however after calibration procedure is complete, headings are correct.

under 5.1 and 5.1.1 instead the heading stay way out even after calibration is complete.

if required, i can produce a video of the calibration procedures under 5.0 and 5.1

i have worked as professional tester in telecommunication industry, so if you have ideas on what type of tests i can perform, let me know.

For anyone having this problem - send pre and post-upgrade backups (zipped) to support@dynonavionics.com with a description of what you're seeing. Before doing that, actually, try recalibrating the heading first (after first looking up your magnetic inclination and total intensity per the installation manual)

 

[gianmarko]

compass shimmy at startup. all a/c electrics are off

http://www.youtube.com/watch?v=T-sIvzlFCaU


here im on the rwy, heading north and not moving.

http://www.youtube.com/watch?v=Mn77BfxBQe0

i stopped filming but after a while the compass tape started swinging more than 150 degs

 

[jhsalden]

Hello Dynon,

AT last I was able to make a backup. Last weeken I have sent you the previous backup and a backup from version 5.1.1. Did you receive this mail?? Or is there something wrong with my computer?

I also noticed the "shimmying" even after recalibration several times.
Please note that calibration is almost impossible.

Regards from The Netherlands,

Joost

 

[dynonsupport]

We did get the email. We do have an issue here that affects some people. The interim solution, by the way, is to restore your backup, and then go to firmware 5.0.3, which is one version older than current. That support program can be found here.

 

[standby]

A question for Dynon support. I noticed the compass shimmy when I first loaded 5.1.1. I have not noted the widespread problems that others seem to be reporting, and 5.1.1 has broadly behaved for me. Now you have a bead on the issue, can youi advise whether I should revert to 5.0.3 for assurance. I do not wnat to get caught by a sleeper bug. Why do "some people" have it, and not others?
Thanks

 

[Garth]

I upgraded my 180 to 5.1.1 at least a month ago. Today for the first time my remote compass was acting up. It would ramdomly stop reading and a message "remote compass not detected" would pop up unitil it started working again. I checked the screw in connectors and they were still tight. I'm reluctant to start pulling the connectors apart looking for a loose wire/connection if there's a chance it could be an erratic software issue. In the sort term it's not abig deal as I have back up via my GPS and a basic magnetic compass. Any thoughts? Thx.

Garth

 

[dynonsupport]

Standby - the shimmy is the only problem that we're really seeing in quantities greater than 1 or 2; we're still getting to the bottom of the shimmy issue, but it has to do with calibrations being interpreted wrong / getting trashed. If we thought that this issue implied some fundamental instability (we don't), we'd pull the release all together (we've done this before when we've found widespread issues). In short - even if you have the shimmy problem - it's OK to live with it if that works for you. Rolling back to 5.0.3 is fine too. We've fixed more bugs than we've introduced in 5.1.1 though.

Garth - We don't think that your issue is related to 5.1.1, though if you rolled back to your last backup, and that cures it, that would tell us somthing.

 

[jhsalden]

I have tried to load Version 5.0.3 however this version is older the version 5.1.1 that is in the system now. I have never used 5.0.3.
I have a backup from V4.0. This was on the D100 before fitting the AP
How can I install version 5.0.3?

Joost

 

[dynonsupport]

You can't go backwards in software unless you have a backup. Given that you have a 4.0 backup, your best method is to restore 4.0 and then upgrade 4.0 to 5.0.3.

 

[jhsalden]

OK, but I only have a backup for the D100. My servos and AP74 are on version 5.1.1. I did not have the need to switch to 5.1.1 before installing the AP.

 

[dynonsupport]

Give tech support a call at 425-402-0433 when you can. We can help you through some of the trickier stuff.

 

[Cottonwoodflyer]

I also have recently installed a remote magnatometer and upgraded to 5.1.1 and on my last flight the D10A indicated "remote compass not detected".  The compass had worked very well since the remote installation and calibration, although I lost the DSAB connection.  After the flight and shut down, I powered back up and the same indication.  Any ideas?
Ron

 

[PhantomPholly]

I also have recently installed a remote magnatometer and upgraded to 5.1.1 and on my last flight the D10A indicated "remote compass not detected".  The compass had worked very well since the remote installation and calibration, although I lost the DSAB connection.  After the flight and shut down, I powered back up and the same indication.  Any ideas?
Ron

That's normally the result of an imperfect connection. I'm struggling with the same thing with my D180. Think I licked it this weekend by gently squeezing the female connectors to make more positive contact.

 

[Chriseleven]

Any movement here? I still have the problem