D100 Autopilot problem: Un-commanded right Roll??

[Foxflier]

Cuising along yesterday in TRK-ALT hold mode my aircraft entered an un-commanded and extreme right roll (past 60 deg) until I turned off the AP and regained control!  This is the third time it's happened over the past two months.  The first two times happened early on during my flight testing in October but the AP has been operating normally until yesterday when it happened again.

Nothing out of the ordinary showed on the EFIS with the horizon bar showing the roll develop.  I've not encountered any pitch problems.  I let it go yesterday until I thought I was going over on my back! 

The first two times the roll developed I was in NAV-ALT mode.  This time TRK-ALT.  I'm now leery of my AP! 

Any ideas what could be causing this?  Do I have a flaky roll servo??   

I noticed some tall towers in the vicinity of where I was flying the first two times.  Could EMI/RFI cause a problem??

I need some help!

Thanks,

Ted

 

[mmarien]

The symptoms sound the same as mine except in pitch. My AP would occasionally pitch up to an extreme angle. It finally completely failed. I exchanged the servo as it was on warranty. I also upgraded to the SV42 and have had no problems since.

 

[Foxflier]

The symptoms sound the same as mine except in pitch. My AP would occasionally pitch up to an extreme angle. It finally completely failed. I exchanged the servo as it was on warranty. I also upgraded to the SV42 and have had no problems since.

Thanks.  I'm also doubting my roll servo (its a SV42) but I'm wondering why it's not reporting an error to the D100.  I'm hoping Tech Support is going to chime in here soon...

 

[dynonsupport]

So the autopilot has a hard bank angle limit, and if it's getting beyond that it's likely that the servo is slipping, the autopilot isn't actually engaged, or that there's something more fundamentally wrong like a servo failure, though I don't think we've seen a failure of this nature before. Since there are a bunch of questions that will help us get to the bottom of this, it's probably best if you get in touch with our tech support team directly. Give them a call at 425-402-0433 when you have a chance.

 

[Foxflier]

So the autopilot has a hard bank angle limit, and if it's getting beyond that it's likely that the servo is slipping, the autopilot isn't actually engaged, or that there's something more fundamentally wrong like a servo failure, though I don't think we've seen a failure of this nature before. Since there are a bunch of questions that will help us get to the bottom of this, it's probably best if you get in touch with our tech support team directly. Give them a call at 425-402-0433 when you have a chance.

I just left a voicemail. 

My bank angle limit is set to 20 degs and works fine during commanded turns.  The right roll pops up during level flight in calm air...just cruising along. I believe pitch tries to hold to the extent it can in a hard bank. I defeat the autopilot (and get the three audio beeps) then recover so I believe the AP is continuing to operate.

Give me a call back and I can answer any other questions.

Thanks!