Tiger Moth,
Re the JAL hydraulics failure, as you may know, the event that caused the failure was a failed pressure bulkhead down the back. When it blew, it took most of the vertical fin with it. The aircraft then would have had very little, if any, stability in the yaw axis. It's amazing they kept it going as long as they did.
I have heard from a controller now retired about a B170 that took off, asked to return with a "minor problem", made a very wide circuit, and landed, following which the copilot (as he was called then) got out, wandered down the back, and removed the elevator control lock. The flight then resumed, normally.