ADAHRS Failure

peter9545

I love flying!
Joined
Mar 4, 2018
Messages
23
Location
Australia
Hi

I have logged a case with Dynon Support but since it is Friday night there I don't expect a response soon, so I am wondering if anyone has any suggestions to help diagnose this problem.

Today I received an error from my ADAHRS 200.

The aircraft was in the hangar. Battery power was 12.1 volts. The hangar doors were closed and GPS signal was very weak (if that is relevant).

The PFD display, basically the attitude information, was constantly rolling and an ADAHRS error was reported. I rebooted and completely power cycled a few times but the error remains.

The system automatically failed over to the ADAHRS 201 successfully and the PFD display was then stable.

I am charging the aircraft battery to full charge, just in case but I doubt this is part of the problem and will try again tomorrow.

Thanks

Peter
 

peter9545

I love flying!
Joined
Mar 4, 2018
Messages
23
Location
Australia
Thanks David. I sent the diagnostic file in last week, no response yet. The fault has mysteriously gone away, waiting I imagine to reoccur during flight. At least the standby ADAHRS failover worked.
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
I just experienced something similar only my ADAHRS failover did not succeed. My RV-10 was in the hanger (still under construction) but the Skyview system had been working fine. I powered up today to demo for some visitors and I received the message ADAHRS FAIL INTERNAL ERROR: PITOT PRESSURE SENSOR. Big red X on primary display. The HDX800 was displaying EMS and the secondary display was displaying the map. I power cycled several times, tried removing the SV-200 from the network and powering up and down. Also tried removing the SV-201 from the network to no avail. The Message window said it switched to backup ADAHRS but I had no attitude display. I dumped the fault log and sent to Dynon but Its Sunday...
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
At the hanger again this morning and now it is working. This is not confidence inspiring. Checking the status of the ADAHRS both are reporting as ready with the 200 unit active.
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
I had removed the primary display yesterday while troubleshooting and had not replaced it. I had tried multiple restarts and was getting the same message. This morning, when the ADAHRS worked, I had not yet replaced the primary display. I replaced the display and the failure recurred. So I shutdown, pulled the breaker on the primary display and waited for a few minutes. On powering up the rest of the system the ADAHRS were working. I ran a network configuration and all was still working. I reset the breaker on the primary display and ran network configuration again. The ADAHRS were then working on all displays and have continued to function through several power cycles.
 

Doug1

I love flying!
Joined
Jun 4, 2016
Messages
35
Hi

I have logged a case with Dynon Support but since it is Friday night there I don't expect a response soon, so I am wondering if anyone has any suggestions to help diagnose this problem.

Today I received an error from my ADAHRS 200.

The aircraft was in the hangar. Battery power was 12.1 volts. The hangar doors were closed and GPS signal was very weak (if that is relevant).

The PFD display, basically the attitude information, was constantly rolling and an ADAHRS error was reported. I rebooted and completely power cycled a few times but the error remains.

The system automatically failed over to the ADAHRS 201 successfully and the PFD display was then stable.

I am charging the aircraft battery to full charge, just in case but I doubt this is part of the problem and will try again tomorrow.

Thanks

Peter
 

peter9545

I love flying!
Joined
Mar 4, 2018
Messages
23
Location
Australia
I also tried again a few days after the initial error and my Skyview was working correctly. I also heard back from support saying I should send the unit in under an RMA.

I have not sent the unit in for test because we are heading into Summer here, just having come out of lock down, and I want to fly. I am quite comfortable doing this as the unit has worked successfully (for several flights) since, I only fly VFR, I have the standby and if all else fails I will ignore the screen and look out the window.

If I flew in IMC at all my stance would be different. I wonder what would happen if it was connected to the autopilot and the failure recurred?

I also asked Dynon support if a high humidity situation could have caused this, their answer might be best summarised as a 'maybe'. The reason I asked this was because we had a small drainage issue at the hangar and in parts it ended up with a 3 inch covering of water and was pretty steamy in there.

So in one way I am OK to keep flying, but I agree with the earlier comment that this type of intermittant failure is concerning.
 

TrevorMills

Member
Joined
Jan 9, 2020
Messages
33
There may not be a connection to the above reports but I had an issue with incorrect IAS being displayed.

The fault first appeared after a flight in high temperatures during the late summer (may be a link to what peter9545 reported) OAT was reporting 36c and humidity was very high. After landing and sitting stationary outside the hangar I noticed that the IAS was reporting 18-22 knots in still air. Rebooting the Dynon system made no difference. I called Mendelsshon and reported the issue and they advised me that the ADAHRS unit must be faulty and to return to them so they could send to Dynon for repair. That was 26th August. In the meantime Mendelsshohn's loaned me a unit so I could carry on flying - great service from them!

I called 2 weeks ago for an update and was told that the ADAHRS pressure sensor had been diagnosed as faulty, had been repaired and was being shipped back to the UK - it's still not arrived but isn't an issues during lockdown!

A couple of thoughts... the first is that the unit had less than a years service on it before failure and the second was the IAS was over-reading between 18 to 22 knots. It could have caused me an issue on approach if the Dynon was indicating 65kts when I was actually flying at 43kts! However the approach felt 'normal' so it may only have over read in still air.

I wonder if there were a faulty batch of ADAHRS made?
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
The problem recurred yesterday. I had just attached the wings to my RV-10 and completed test of all lighting. I booted up the system, reconfigured network to add roll servo and magnetometer and powered down. On power up the ADAHRS again indicated a fault with the pitot pressure sensor on both the 200 and 201 unit. I powered down the system, pulled the breakers on the two HDX 1100 and powered on the HDX800. System came up with ADAHRS still in failed condition. I ran the network configuration again and the ADAHRS both came back. Put the breakers in for each of the HDX1100s one at a time and they came up as well and ADAHRS are working again. Tried power on again today, still working... Intermittent issue, oh joy!
 

rfazio1951

Member
Joined
Feb 11, 2010
Messages
354
Tom, I’ve seen this kind of error on a system where the network wiring was not connected correctly, loose connections, and / or incorrect wiring. I mention it because you saw it come back on after a network config. Are you using Dynon cables or home brewed? Make sure they are all tightly screwed in.
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
The cables are home brewed. They have been working fine for more than a year and the plane has been sitting in the hanger as I work through final assembly. I did recently add a yaw damper Servo and a “Y” cable at th pitch servo.

Any thoughts on how a bad network connection could lead to only a ”pitot” sensor failed indication on both ADAHRS?
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
No I have not, great suggestion. I'll also do that and the static sensor cal on Friday.

FYI, Jeff at Dynon suggested disconnecting the pitot and static lines from both sensors and doing a functional check on each by covering the port with my thumb and pressing while watching airspeed and then altitude respectively. Both ADAHRS preformed as expected (airspeed increased and held, altitude decreased and held)
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
I have left the system open since Thursday (4 days) with no recurrence of the issue (after many startups). I did the zero airspeed calibration as well as the altimeter offset on Sunday. I will verify the lines are clear and reattach to the units.
 

Tom_RV10

New Member
Joined
Apr 22, 2020
Messages
16
I reconnected pneumatic lines yesterday, failed again this morning. Powered down, disconnected pneumatic lines, powered up. Problem gone. Reconnected pneumatic lines while powered all still good.
 
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