Been a while since I worked on the Electra as a maintainer. A few practical notes I can add; when we would deactivate the Autopilot, we would do so by depowering via a three phase ganged circuit breaker. The AP amp & cb were in the avionics rack on the flight deck at floor level,just behind & to the right of the FE's position. I flew many times on the flight deck & as the Electra was prone to Dutch roll,we would pull & reset the AP cb. It is extremely (impossible) unlikely for the flight controls and engine power controls to mechanically interfere. The engine controls being routed along the wing leading edge & flying controls along the trailing edge. They are also physically separated on the flight deck & within the fuselage.