Very scary moment

[flyboy0681]

I'm just glad you're still around to tell us about it.  That had the potential to be ugly.

 

No kidding. Glad I wasn't the subject of a new topic here reading: "Mooney down in Venice".

 

I spoke to Autopilot's Central today and had a very good conversation with Bob. He said that what I described is most probably the trim switch, which others here have stated, and that the autopilot going into "error" mode by beeping is one indication of that condition. So it's off to the shop we go.

[marks]

My trim switch is very touchy.  When I trim the plane up for cruise I often just flick the switch in up or down direction for a tenth of a second and I tend to also flick it back into position.  Very often the switch over corrects or stays in the wrong position for half a second and I reposition the switch without even thinking about it.  When I bought the plane seven years ago I experienced just what you did, but now I don't even think about it.  The simple question is this: when the trim starts to run away does the trim switch fail to stop the runaway situation?  If repositioning the switch stops the runaway trim, then there's your answer.

[flyboy0681]

The only time I use my electric trim in the air is simultaneous to flap deployment. Then I use it again on the ground to set trim for takeoff. Everything else is with the manual trim wheel, which, at least on my Mooney, is much better for small adjustments.

Jim

 

That's pretty much how I use the electric trim. Not many know that the trim and flap motors move at the same speed so applying trim at the same time as the flaps makes for imperceptible attitude changes. Compare that to Cessna's where applying flaps makes the plane reach for the sky as passengers try to hold down their lunch.

 

In the meantime, we will be bringing the plane in to have the trim switch looked at. Hopefully parts are readily available.

[Jeff_S]

I have to admit, I use the electric trim so much I have to remind myself where the manual trim wheel is! I've actually added this to my run-up do-list, to physically feel the wheel move with electric trim and manually give it a quick turn as well just to be sure. And when I was doing my transition training, my CFI coached me to do the same thing as Flyboy...pull back on trim while pushing down on flaps to maintain neutral attitude. Works like a charm.  (Similarly, or oppositely I guess, push down on trim while dropping gear to achieve same effect.)