Autopilot & Trim disconnect switches?

Curious. How many people that have autopilots also installed a disconnect switch for it? Is that switch within reach of your passenger seat? How many people have a trim disconnect switch? Ditto on the location - can your passenger reach it?

Today's Daily Double: Any reason NOT to wire the disconnect for both systems to the same switch? At the moment you get the sense that the plane is flying itself in ways you don't like, why not just kill both suspects?

For Trim

For trim this is why I like the Cessna 182 (newer) split double rocker trim switch. You have to press BOTH to get it to move. A failure in either switch does nothing. I'd rather have the trim NOT run away rather than have it run away and be fumbling for the disconnect switch or find the breaker.

I've suggested this before. Someone priced the CESSNA part and said no way! WELL, you don't have to use the CESSNA part in order to apply the Concept.

Now, regrettably that isn't an option if your stick has a bunch of built in switches, unless you can somehow retrofit it in. I used one from https://www.pioneercontrolgrips.com and got the blank plate from them so I could install my own switches.

A/P disconnect is on my stick grip. If there is a trim runaway, the breaker has a red collar. Neither are reachable from the back seat.

I also have AP disconnect on the pilot stick, plus a physical switch on my panel that directly cuts power to the AP servos. For trim, I do not have the ability to disable from the cabin. However on my second test flight, I verified that the plane is controllable at full up trim and full down trim, and my G3X is configured to limit trim presses to 3 seconds at a time max. So I feel I am fairly safe from runaway trim.

I have a non touch G3X and have a "KILL GEORGE" momentary push button that stops George when I don't like the way he's flying.

I have A/P disconnect switches on both pilot and copilot military style grips. The TruTrac Vizion A/P head also can quickly disconnect the A/P by pushing the button. Autopilot is also on its own CB.

So far (knot on wood) I haven’t needed to quickly disconnect the A/P except for when I’ve done something stupid - which unfortunately is not a rare occurrence.

I have AP disconnect switch on the sticks and also a power switch on the panel right next to the AP controller. I also use a trim power switch on the panel.

I don't, but wish I did, have autopilot disconnect on the stick. There have been times on final when I had to avoid birds and I just overpowered the autopilot, then had an angry autopilot that wanted to go back to its programmed mode.

I've not messed with control wheel steering because the switch is on the panel, but I'm wondering when it would fit in with my normal flying.

Here's my workaround for not having control wheel steering: When I do an "autopilot assisted takeoff," which I do on an IFR departure, I engage the autopilot immediately after flaps up at 80 knots. (On the RV-9A, flaps 10 keeps the nose down on liftoff so you can see the runway, and that was a learning lesson on the first narrow runway takeoff with flaps up.) Turning on the autopilot give pitch hold and wings level. As speed increases, I engage a specific pitch mode so that the plane will level off at the desired altitude. I don't take off in heading mode because sometimes ATC assigns a heading for after takeoff, and I don't want the turn to start at autopilot engagement right over the runway at 80 kt.

I have 3 easy to reach choices. The Dynon screen, toggle breaker switch and disconnect switch. All accessible by co-pilot seat. In addition installed level switch easily accessible by both seats.

Switches

I did both.

JET14 said:

I did both.

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I would take a hard look at the location of that avionics master, if that is what AVI indicates on the rocker.

I have a stick mounted AP disengage switch. In addition, directly in front of the left seat, there are two pullable breakers, one for AP, one for trim. There is a painted rectangle around these breakers, making them easy to find quickly. The drill for a trim runaway is to pull both breakers (the Trio AP also has auto-trim). While I can reach these CBs from the right seat I have never made it a point to brief non-pilot passengers about them.

fl-mike said:

I would take a hard look at the location of that avionics master, if that is what AVI indicates on the rocker.

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I thought that too. I’m amazed at how many times I’ve seen that.
Not a big deal for a day VFR plane - probably just give you a fright. But it dosent take too much imagination to see what could occur whilst doing your landing checks on an ILS or RNAV in the bumps or dark.
I had switches under my GDU on my RV7. Admittedly they were toggles and only for the lights, but they got hit more than once while touching the screen in the bumps.

For my AP, I run a disconnect/CWS the stick. V useful. Gets used every flight.
My breakers for the AP and trim are out of the way so I have a trim power switch easily accessible to the pilot.

But… Tbh I think most of these fears about runaway trims and autopilots are unfounded with modern hardware and avionics. I’ve never heard of one runaway. Not saying it hasn’t happened, but I’d like to hear about it.
Moreover, the autopilot is easily overpowered and all RVs can be flown with no trim.
The most likely source of failure is probably going to be because of overcomplicating a simple aircraft.
Take the example of people not RTM about ESP.