Cirrus SR22 / DFC90 servo arrangement - how does it work?

I have of course read all the manuals and quite honest might not remember all the details over time. Good point to look at it again.

All I know (I have a SR22 G2 with the DFC90)

• all SR22's DO have a PITCH servo (plus the electric trim)
• the SR20 normally does NOT have the pitch servo, the DFC90 uses the trim "cartridge" then
• neither SR20 or22 normall have a ROLL servo. The DFC90 will work fine without it, but maybe even a little better WITH a retrofitted roll servo

The TURN COORDINATOR only delivers data for comparison. A WORN OUT Turn Coordinator will make a "AHRS MISCOMP" message come up, meaning (in 90% of the cases) that the TC has to be overhauled. My PFD sometimes shows "AHRS MISCOMP" after 60 degree steepturns or other aggressive airwork. I will let the TC be overhauled soon.

Even with the "AHRS MISCOMP" message the A/P will stay on and fully functional if "Release 2" is installed. If the "AHRS MISCOMP" comes up on the ground, the A/P cannot be used and the aircraft must be handflown.

WIthout "Release 2" the A/P will go offline in flight – which is a very good reason (among others) to upgrade to R 2.

If the "AHRS MISCOMP" error message comes up then the Autopilot will stay ON and work properly if the reason is only the Turn Coordinator (which is only used for comparison) – if you have Release 2 of the A/P software. WITHOUT R2 the Autopilot will disconnect.

But if you have the "AHRS MISCOMP" message on the ground then you cannt engage the A/P and have to hand fly. Recycling the Avionics switch can sometimes help in this case.