Autopilot Rolls Into Turns Like A Fighter Pilot

[swatson999]

I have a SV Classic Touch, and it exhibited this behavior.

 

[RV8JD]

I wonder if this problem of increased aggressive roll is just happening on Skyview HDX versions, because updating to 16.2.4 on Classic D1000's in my Bristell NG5 appears to have made no difference to roll at all!

I have a SkyView Touch, and I had the issue with v16.2.4.

As I mentioned earlier in the thread, maybe it was a change to certain servos or the AP interface to the servos, based on Dynon's early reply in post #26. I have SV-32 servos.

 

[Seagull]

I made a small course with left and right turns, the legs were 1-3 miles long. I flew the course with 16.0.1 then landed and upgraded to 16.3.2, and re-flew the same course. There was no difference in the way the plane navigated the course or the turns. I flew both at about 4400' and 100kts.
The photos were taken in the same turn of the course, you can zoom on the Dynon to see position.

What I did notice is the alert audio has increased with 16.3.2. I had it at 52% in 16.0.1 and had to lower it to 15% in the latest 16.3.2.

the course

firmware 16.0.1

firmware 16.3.2

 

[Dynon]

A short update here: We're still driving to root cause on this, and don't yet have it identified yet. We plan to address the behavior in our next software update, which currently doesn't have a scheduled release date. Nothing in the 16.2.4 ostensibly should have changed autopilot behavior at all, though, so it's a bit perplexing.

 

[Seagull]

Something new I just found out is when I bank hard I get an audio alert “bank angle”. How do I get rid of that, I can’t find any reference to it in the menu?

 

[RV8JD]

Something new I just found out is when I bank hard I get an audio alert “bank angle”. How do I get rid of that, I can’t find any reference to it in the menu?

It's a new alert with v16.3, as of May 2022.

"Bank Angle - The autopilot is engaged, and the bank angle of the aircraft is greater or equal to set Bank Angle Limit plus 5 degrees. The alert is cleared when the autopilot is disconnected, or the bank angle is less than the set Bank Angle Limit. The audio alert repeats every 5 seconds until cleared."

Next time, try pressing the AP disconnect button twice within one second, to turn off the Flight Director and the alerts that go with it.

See this thread for more info:

Nuisance "Bank Angle" Warning after Software Upgrade

Anyone else having this? Upgraded to the latest software version yesterday and flew today....the flight involved assertive autopilot off maneuvers (generally non-aerobatic) as part of formation flying (rejoins, etc.) 60-70 degrees of bank, pitch +/- 15 degrees. Any bank angle over about 30...

forum.flydynon.com

 

[Seagull]

I

It's a new alert with v16.3, as of May 2022.

"Bank Angle - The autopilot is engaged, and the bank angle of the aircraft is greater or equal to set Bank Angle Limit plus 5 degrees. The alert is cleared when the autopilot is disconnected, or the bank angle is less than the set Bank Angle Limit. The audio alert repeats every 5 seconds until cleared."

Next time, try pressing the AP disconnect button twice within one second, to turn off the Flight Director and the alerts that go with it.

See this thread for more info:

Nuisance "Bank Angle" Warning after Software Upgrade

Anyone else having this? Upgraded to the latest software version yesterday and flew today....the flight involved assertive autopilot off maneuvers (generally non-aerobatic) as part of formation flying (rejoins, etc.) 60-70 degrees of bank, pitch +/- 15 degrees. Any bank angle over about 30...

forum.flydynon.com

Thanks, that solved it. I have the AP button on my grip so it is real easy.

 

[jcarne]

Gents, Don reached out last week with news of engineering identifying and fixing the issue with the autopilot. I had a chance to test it today and everything seems to be back to working. I could not replicate the previous issue with either the heading/track bug or the nav feature. I only have about 1 hour on the update but I haven’t noticed any issues as of yet with anything else. So if you want a fix for the autopilot you might reach out to Don as I don’t know when they will issue a full update. I will do some approach testing tomorrow and if anything weird is found I’ll report back. The update he sent me was 16.2.7.9443. If you are newer than that you will require two other files from him as well as a force network load on the modules (a lot easier to do than it sounds).

 

[Seagull]

Thanks for the update.

 

[RV8JD]

Gents, Don reached out last week with news of engineering identifying and fixing the issue with the autopilot. I had a chance to test it today and everything seems to be back to working. I could not replicate the previous issue with either the heading/track bug or the nav feature. I only have about 1 hour on the update but I haven’t noticed any issues as of yet with anything else. So if you want a fix for the autopilot you might reach out to Don as I don’t know when they will issue a full update. I will do some approach testing tomorrow and if anything weird is found I’ll report back. The update he sent me was 16.2.7.9443. If you are newer than that you will require two other files from him as well as a force network load on the modules (a lot easier to do than it sounds).

I'm glad they found the issue (and a fix). Did he say what caused the problem, since Engineering originally indicated that they made no changes that would affect the AP performance, and this AP bug seemed to affect some folks but not others. Curious minds want to know.

I would be hesitant to try this version of the SW, as it may not contain the Tach Time fix, which also affects my airplane.

Thanks for the info.

 

[jcarne]

I'm glad they found the issue (and a fix). Did he say what caused the problem, since Engineering originally indicated that they made no changes that would affect the AP performance, and this AP bug seemed to affect some folks but not others. Curious minds want to know.

I would be hesitant to try this version of the SW, as it may not contain the Tach Time fix, which also affects my airplane.

Thanks for the info.

He did not say, I am curious as well. I am also curious on the tach time as I had that issue too before 16.3. I will look at the data tomorrow and see if that is fixed too. I’m hoping so as this is 16.2.7 and not 16.2.4 where I really had issues.

Since I am doing instrument training right now an autopilot fix is higher on my priority list than tach time but I’m really hoping that fix is packed in there as well.

 

[jcarne]

Okay guys, more testing done today. The autopilot seems to be working normally again. As mentioned though by RV8JD the tach time issue could be back. I can confirm that it is back. I have reached out to Don to see about getting a fix. So, if you have different ignition types and don't want the tach issue to deal with I would hold off until an update is available with both fixes in it.

As far as the autopilot goes it seems to fly normally again including approaches. You will however have to tune the pitch axis again. No biggy as this is pretty much standard ops with any update it seems. Hope this helps.

 

[Riseric]

Currently running 16.2.4 and I also have the sharp roll when in NAV mode but not at all waypoints.
Considering updating to 16.3.2 and wondering if a fix for that behaviour is included or not?

 

[jcarne]

Currently running 16.2.4 and I also have the sharp roll when in NAV mode but not at all waypoints.
Considering updating to 16.3.2 and wondering if a fix for that behaviour is included or not?

Nope, as far as I know the only "update" that has the fix is the test one that Don sent me a few weeks back. (see above) However, it brings back an issue with tach times if you have different ignition systems.

 

[djones]

Those of you who have experienced this issue, we now have a version that includes a fix for the problem. Engineering has asked me to find a few people to test the fix. Please contact me at support@dynonavionics.com and I can send you a link to the software.

 

[Marc_J._Zeitlin]

Those of you who have experienced this issue, we now have a version that includes a fix for the problem. Engineering has asked me to find a few people to test the fix. Please contact me at support@dynonavionics.com and I can send you a link to the software.

Can you please explain what the problem was and what caused it?

Thanks.

 

[RV8JD]

Those of you who have experienced this issue, we now have a version that includes a fix for the problem. Engineering has asked me to find a few people to test the fix. Please contact me at support@dynonavionics.com and I can send you a link to the software.

Don,

If it also includes a fix for the Tach Time issue, I'd be willing to try it. Does it include a fix for that issue also?

Thx.

 

[RV8JD]

I volunteered to fly the new software load per Don’s request in Post #75. I had previously flown v16.2.4 for 5 flights and experienced the Tach Time and Roll Autopilot issues that I couldn’t live with. I subsequently downgraded back to v16.0.8.

Yesterday I loaded and flew the new v16.4.RC0.9553 software (for the Classic models) that Don provided (on Sunday no less!).

Summary: The new SW fixed both the Tach Time issue and the autopilot’s aggressive and unpleasant roll-in characteristic when changing heading/track. I exercised all the modes I could in the AP at cruise speed (~175 KTAS) and at lower speeds, at a few different altitudes. The Pitch AP response to its various modes seemed unchanged from v16.0.8.

The AP response feels very nice again. I’ll keep this version of the SW loaded on my SkyView Touch!

Details: For reference I have a Van’s RV-8 with a single 10.2” SkyView Touch (SV-D1000T), SV-32 servos, and several other Dynon components. I do not have an IFR navigator. I have a Lycoming YIO-360-M1B with a Slick impulse-coupled mag and a LSE Plasma III Electronic Ignition.

I updated the SW from v16.0.8 to v16.4.RC0.9553 Classic and the update went fine with no issues. I flew for about 1.7 hours, all on AP except for the takeoff & landing and a few AP manual disengagements, reengagements, and using CWS mode. I mostly tested at cruise speed (~175 KTAS), but did some testing of some of the Roll & Pitch AP modes at lower speeds. I changed direction many times (and with varying rates of turning the knob and the amount of direction change) using the Track, Heading, Nav and OBS modes.

Problem Cause: As for the reason for the Roll AP issue, from Don at Dynon: “They introduced a bug that basically disabled the roll gyro feedback gains, (pitch too, it just didn't show up as much as there is also a vertical speed rate limiter in use)."

I appreciate the updated SW with the bug fixes.

 

[TrevorMills]

I also volunteered to try the new software (v16.4.RC0.9553) and have just got back from a 4 day trip. Upgraded to the Release Candidate software from 16.2.4 with no issues. Reset the AP 'Roll' settings back to defaults before flying.

Flew all flights over the 4 days on autopilot except for take off and landing.

I can report a similar experience to RV8JD however my cruise is much slower at 115 kts. All turns were as before. Very measured with no signs of the aggressive nature the previous SW exhibited. All modes checked and several quite tight turns programmed in which included 'S' turn reversals.

I didn't notice or have problems with the Tach Time so I can't comment on that aspect of the SW.

Thanks to the Guys and Gals at Dynon for their response to resolve the issue.

 

[ge]

Anyone with an update on this? Is there likely to be a Software update anytime soon?