Hi Ted
I had a student with his left leg amputated above the knee and he now flies his modified -7A all over the country. He welded arms to the top of the rudder bars, that attach to a bellcrank, so the when he pulls the right pedal toward him, the left pedal is depressed, as shown by this photo:
He added a stirrup to the right pedal to accomplish this:
He mounted his throttle on the far left of the dash so that he could also use differential brakes, mounted on two levers in the center, so he can also steer with the brakes in his right hand:
I'm not sure how the -12 pedal geometry is designed but these pictures should give you an alternate idea. His left ankle doesn't pivot, so he mounted a small wheel to two arms screwed into his Nike's, so that it can roll back 'n forth as the left pedal moves.
We practised taxiing using only his right (good) leg by pulling it back, we turned left and pressing, turned right, over and over until he became pretty adept at it. That, and the dual handbrake setup did the trick. He's been to Yellowstone and Massachusetts from his base in Barnwell, S.C. and many other places without any landing/groundlooping incidents after the FAA issued his SODA in a Cherokee 140.
If you'd like either call or PM me if you'd like to speak/communicate with him.
Best,
