SANDEL and Avidyne heading miscompare

Hello I am flying a SR-22 that has the “avionics-B” package. This is simply put an Avidyne MFD without a PFD. Instead there are traditional round dial instruments and a SANDEL HSI.

In flight there was a substantial difference between the HSI, wet compass, and the MFD. Is there some way to slew the HSI to the wet compass, like a traditional HSI? I don’t see any slew/slave switch but I may be looking in the wrong place. If someone knows this system that would help.



The Sandel has a Magnometer in the right wing and a gyro under the rear seat. It should be pretty accurate if those are working correctly. Mine always did.

You could have a settings problem or something more sinister. They are known for having problems with stuff like that after poor reseating of the unit after a bulb change (poor connection at the back). They also suffer from an overly tight harness that will pull wires and give the same result.

From a distance it is hard to say which problem you have. Many of us old Sandel owners have been converting to glass panels. In my case mine was working well but I wanted the additional functionality.

Sandel does not support that unit anymore so when they have problems people have been installing Aspens or G500’s.

You might consider joining COPA. There is quite a bit of good information about this stuff on the member side. Good luck.


I can PM you tomorrow the name of the technician that has helped me diagnose a number of these type issues. He works for Sandel and been extremely responsive. Each time they have helped me determine if it is the Gyro or something different. Recently it was the Gyro under the seat that needed overhauled. Before it has been the unit itself.

Sandel HSI gives your heading. Depending on setting MFD can show heading or route track. So first thing to do is verifying MFD settings