Originally Posted by
Concours77
If seized, the unit prevents all control of the ailerons, since “manual control” operates through the hydraulic arm.
The disengage handle when pulled disconnects the control cable from the boost unit for aileron, rudder or elevator, and simultaneously alters the mechanical advantage. The full range of the control surface is reduced by about half, and the force required by the pilot is about doubled.
Pulling the engage handle reverses the action.
I discuss this in the new chapter currently at
https://we.tl/x0L59Bpfmj and it will be in the next release.