If we look at the Ups crash at Birmingham USA . Airlines and union get thrown out of FAA enquiry. Airline says self management of rest. Union says regs.
Yes but they both said it in public which is a big no-no when party to the investigation. The NTSB are quite strict on those things (unless its the FAA making the public comment).
The three big challenges here will be:
1. The perception by unions/employees that airlines are attempting to regulate their time off.
2. There is an empirical test for alcohol. Fatigue is less black and white and difficult for the employer to prove if disciplinary action for failure to manage fatigue is challenged in court. The unions like it that way as it makes protecting their members easier. Airlines like it that way as it is difficult to prove that the company did not comply with FAA/EASA/CAA requirements.
3. There is only a general definition in any regulations that I have seen of 'rest' prior to duty, and no specific regulation when it comes to physical exercise or sport. Example: for one crew member a round of golf is a relaxation, while for another it is (as George Bernard Shaw called it) "A good walk ruined". Similarly, for a regular runner a 5 mile jog is refreshing but for somebody more sedentary this distance could leave them seriously fatigued. It is practically impossible to coalesce this variable for an entire industry of diverse human behavior into a single
one size fits all regulation.
Until there is a definitive accepted test that can be also be self-administered by the employee to ensure compliance then this grey area will remain. We have also drifted away from the entire concept of personal responsibility for fitness to fly. FRMS is a good concept, but it will enhance the airlines ability to transfer the responsibility for the accident back to the individual.
As an investigator, I have come across multiple instances of crews within their duty period but still fatigued. The two are not the same.