What would be involved in disconnecting one set of controls in an aircraft?

Question

Every aircraft I've seen has two sets of controls, even aircraft with only two seats. For any number of reasons - we'll go with "This pre-teen is super excited about aviation and wants to fly, but has motor control issues" - a pilot may find themselves with a passenger who can't be trusted to not fuss with those controls.

My understanding is that in anything that isn't fly-by-wire, those controls are mechanically/physically bound together (along with the control surfaces), so I assume there's no cutoff lever that would allow the PIC to positively assert control over the aircraft.

With that understanding, what would the process be to (legally in the U.S., and ideally reversibly) disconnect the controls for one seat?

Obviously each aircraft's mechanical specifics will vary, so the physical part of the job should be summarized but I'm interested to know if such modifications (which presumably don't meaningfully alter the weight and balance) automatically require the aircraft to be registered as Experimental and whether or not this would be mechanically straightforward or a massive undertaking.

EDIT in response to comment:

If a specific plane is required for your answer, assume a Piper J-3 Cub or some other fore-and-aft seater where a rambunctious passenger couldn't just lean over and grab the PIC's controls. If there are specific aircraft where this is easier to effect than others, that's also interesting and should be included in an answer.

Answer 1

No there isn't until you get to transport category airplanes that have dual redundant control path systems, with left/right control disconnect systems, to cater to system mechanical jam cases.

A few airplanes have control yokes that can be moved to either pilot's side or the passenger's side. The DeHavilland Beaver and Beech Bonanza are like that. When the yoke is on your side, the passenger only has rudder pedals.

On most GA airplanes with dual controls, they are always connected together, so the only way to keep the passenger's hands off is to remove the control itself from the airplane, and you'll sometimes see airplanes with the right control column removed, like planes used to drop jumpers, or planes never used for dual instruction, like bush planes, so they just want the column out of the way.

On tandem airplanes like a Cub, the control stick just goes into a socket retained by a bolt or pip pin, and frequently you'll see the passenger seat's stick removed from the socket to preclude any funny business.

In the end, if you're really worried about that sort of thing, I'd worry more about a passenger in your car that waits until a truck is approaching on a 2 lane highway and reaches across and yanks the steering wheel when the time is right. Nothing you can do about that, and it's lights out in a few milliseconds.

In the plane, you'd have more of a fighting chance, especially if you had some altitude. And if that was to happen somehow, there is a trick I learned when instructing in gliders to deal with students that freeze on controls - you choke them, either grabbing the throat with both hands, or a little karate chop to the front of the throat. They'll let go (fortunately I never had to actually try it).

Answer 2

Many tandem two-seaters have an easily detached rear (or in some cases front) control stick. Combine this with a simple rudder pedal cover, and a passenger is locked out of all controls other than throttle. For aircraft built with this option, there is no regulatory effect from detaching the removable stick.

Next step up is a central stick (found in some side by side two-seaters) or throw-over yoke, most commonly seen in Beechcraft Bonanzas. The Bonanza versions with this setup also had folding rudder pedals, so a passenger in a front seat would again have no controls other than power lever. Built/certified this way, so FAA doesn't care what configuration you fly in (BTW, the Bonanza throw-over isn't readily switched in flight, making this version less desirable for instruction).

Plenty of homebuilt two-seaters have been constructed with single controls -- registered as experimental anyway, as long as it passed an inspection in the setup you'll be flying, good to go.

Now, if you start altering a certificated airframe by disabling or removing primary controls from the second seat, you will start to run into regulatory questions, but there are so many other options that don't require this that I'd handle it on a case by case basis -- if you own an airplane and want to take this enthusiastic disable teen on a flight, you should consult your local airframe mechanic and inspector.