Tumbling horizon+changing altitude

[Dirk]

I made an upgrade from EFIS D10 to D10A and reinstalled the unit. The instrument behaves a little odd since then. The first thing is: Every now and then at runup the horizon tumbles anround, the heading is off by 100+ degrees and the turn rate indicator shows full left deflection. After 5 seconds it recovers, but the turn rate stays at full left. At next or third boot it comes up fine.
The second bugs is this: I calibrated the EFIS to my steamgauge with the MORE MORE SETUP MORE MORE MORE ALTADJ procedure (I had to set-220), say at 30 inch HG both units show 250 feet. The next day, with the same QNH it shows 310 feet. Of course, it should show 250. (I know about the autocorrection function, but if I set the QNH to the QNH of the steamgauge it should show the same altitude the gauge  shows.)It is off every day. Sometimes I go flying, airport altitude 250 ft, EFIS 250 ft, short hop, and after touchdown it shows something 50 to 150 ft off. Even without flying and powering up and down at the hangar it is not corresponding with my steamgauge (and that one is fine, I rechecked it with several other aircraft in my hangar.Every time I start the EFIS, the altitude comes up with say 300 ft and slooowly creeps down to 250ft over a period of 2 minutes, Static line seems to be OK, no water, no leaks. Any ideas? I think the first bug is software-related, my Version is 5.0.0 and the EFIS is connected to a EMS D10 via DSAB, it has an internal backup battery and is wired to a Becker Mode-S Transponder.
I hope that I don’t have to send it in for service, I’m located in Germany and the goaround time has been 8 weeks this winter.
Cheers from Germany,
Dirk
Vans RV4 D-EEES

 

[dynonsupport]

The attitude/turn rate/heading issue is one that, if it continues, would warrant a trip back here for a look under warranty. Altitude is actually normally inhibited for 30 seconds after power up because it takes some time for that reading to stabilize, and it can take a few minutes for it to reach ultimate stability. It normally stabilizes a bit closer quicker than you're seeing, though.

 

[Dirk]

Today I made this to be shure there is no clogged static line: I unscrew the static line from the instrument and fired it up. The altitude starts reading 330 feet at first and comes down to 290 feet after 5 minutes (engine off, in my hangar), but it should show 250, that is what is showed yesterday with same air pressure at the airport. I go flying for 5 minutes, at runup point it shows 250 feet, after I recalibrated it (instrument running for about 10 minutes), after landing it shows 170 feet, same QNH, and no static line connected to the instrument. With static line it's just the same. The old D10 was stable as hell with altitude, but now with the upgraded D10A altitude is nothing to bank on. All other instruments (steamgauges and EFIS-values are correct)Any suggestions?

 

[dynonsupport]

There's not much else you can do in the field. We'd need to take a look at it here.

 

[Dirk]

I what timespan do I have to send it back? I made the upgrade to the D10A via the german distributor, and can live with the bugs til the end of season, but would it be fixed under warranty by than, or should I put it in the mail this week? The goaround has been 8 weeks and I'm eager to fly this spring
Cheers, Dirk

 

[dynonsupport]

From a warranty standpoint, you're fine for 3 years from upgrade. No worries there.

 

[Dirk]

Today the EFIS D10A came back from repair and I was eager to install it. At first I threw the backup battery in, powered it up, and all was fine, correct stable altitude, no tumbling horizon, just ok. I installed it in my RV, powerde it up, and: Tumbling horizon, altimeter 80 feet off, just as before. Damn...thought about returning it immediately, but then I unplugged the connector, started it with the internal battery, and:bingo, everything fine...? Scratch head, should it be my wiring, causing this?? I opened up the connector, but everything was fine there. I pulled the fuse for keep alive power for that and somehow forgot to engage it after closing the connector, powered up and all was fine. Should it be the keep alive? After a dozend trials it's obvious: without keepalive-power connected, it's all fine, as soon as the keepalive is connected, the EFIS goes mad. I have the internal backup battery, so there is no need for keep-alive, if the RV is flown frequently, so I just disconnected the wire and after 2 hours of flying there are no problems. Before I upgraded to D10A, there was no problem like this, so I would suggest to all with tumbling horizon and altimeter problems the following: Disconnect the keep-alive current and look, if it's all in the green. And to the Dynon guys: It seems to be a problem with keep alive power in connection with those problems after upgrading to Version 5.
Cheers, Dirk

 

[dynonsupport]

We're skeptical because of the lack of any sort of electrical or logical connection between keep alive power and the sensors and software that generate the instrument readings. If you haven't already, call us at 425-402-0433 or email support@dynonavionics.com