Very unfortunate for the PA-31 pilot, it seems he kept it in the air for a while before succumbing to the introduced issue.
For whatever reason the possibility of control failure, either by accident or introduction, was something that interested me for a long time. I think this came from reading about Roy Chadwick (
https://en.wikipedia.org/wiki/Roy_Chadwick) and what happened to him and his team when the Avro Tudor prototype crashed as a result of crossed-cables (
https://www.baaa-acro.com/crash/cras...dford-4-killed). Following that I spent several hours in the air and on simulator practising for various possible issues I could think of. The simulator was particularly good because you could actually introduce a real failure and/or cross-up.
With regard to crossed aileron cables I came to the conclusion that, in a dual-control yoke-style aircraft, it should be possible to reasonably control by grabbing the inside handgrip of each of the two controls, with elevator issues try to use trim if possible, and with rudder problems you might correct a little with aileron (or async engines if in a multi). One important finding was to be
very deliberate if you used any crossed or broken control; my view is that it was better to leave that control alone and remove hands or feet from the equipment if possible in order to prevent inadvertant application.
Another thing I did ever since was to specifically check for control-surface sense when doing a 'full and free' check. In all my training this had never been taught, but made absolute sense to do.
As it turned out I was lucky in that the only time I came across such an issue in anger was when doing the inaugural flight of a PA-34 after it had been introduced to the local register from another country. As a result of that it required a reasonably extensive teardown and reassembly, during which time the engineers had managed to mess up the elevator trim. The result was that at take-off the machine pitched up sharply and could have stalled around the end of the runway had I not been able to react quickly enough and maintain sufficient forward pressure on the controls for the subsequent return to fix (this required somewhat more force than one might think!). At this time I was regularly test flying aircraft after they'd had work on them, which probably helped, but of course this turned out to be one event I'd not practised for...
munnst do you have a reference for the Halifax story? It sounds interesting.