Not sure how mortgages and overdrafts compare to be honest, but the only way that I can view it is that the bond was signed by the employee and CHC, not First Reserve.
If you choose to join the largest helicopter company in the world, believing that you are getting job security, a long term career etc etc, then how do you stand with the uncertain future now of possibly getting broken up and sold up in parts?? After all, First Reserve can do anything they want to the various business units of CHC.
Surely that training bond is now null and void as you should have the right to move on if you are unhappy with the situation, without incurring the penalty of the original contract that you signed with CHC, who effectively no longer own you.
