AP-74 and runaway trim?

[cjohngraham]

I have a HDX, AP-74, and Ray Allen elevator trim servo in my RV-7A (no manual elevator trim). I also fly 182s with G1000 for CAP. Recently, CAP issued the following safety alert video concerning an autopilot-induced runaway trim condition: https://vimeo.com/321309420/dd3cf0c744

Is this sort of failure known to occur with the Skyview/AP-74? For runaway trim, Ray Allen says to actuate trim in the opposite direction for 3 seconds. Is that sufficient? Thanks.

 

[Raymo]

The AP Button panel includes runaway trim control (kills output if engaged for > 3 seconds). From what I've read, the problem is usually within the servo, though.