Watching the show again last night, I was struck by another comment. Words to the effect that "only the pilot can decide if he is fatigued."
The science on this is in. Fatigue impairs judgement and leads to irritability and impatience. Fatigue itself impairs the ability to recognise fatigue and take appropriate action.
This is why we now have fatigue management systems (in various forms) in place. If the computer states you are fatigued, then you are fatigued. If you feel fatigued, then you should overrule the computer even if it says you are OK. Maybe you had a poor sleep in a strange bed, or maybe you are getting a cold. So yes you should always rely on your perception of fatigue. This is an extra line of defence. But this is very different to saying you should simply rely on your own perception.
It is a circular argument to say you can't reply on your perception and need to use an objective pre-determined system, and then after it has gone wrong and if fatigue management policy was not followed say something like "only the pilot can determine if he is fatigued." The agenda here appears to be to blame the pilot and ignore the underlying corporate problems.
Delaying the return trip may (or may not) help. I am sure we have all struggled to sleep during a rest period. Uninterrupted restful sleep in a strange environment does not always come easily. Being off-duty and getting adequate sleep can be quite different things. You can still be fatigued even if you have had an adequate off-duty period. Dom doesn't seem to know how much sleep he got and has given different answers to this. Whatever it was, it does not seem enough. So what if he elected to delay for another 10 or 12 ours. What he he still didn't sleep properly and was still not rested? What if the FO had slept during the initial rest period, but then couldn't sleep when this rest period was extended? Because trust me, this is the real world.
I also wonder about the effect on the doctor or nurse when we delay. They sometimes have to keep working when we clock off. Sure they are responsible for only one life, not six.
I don't have any easy answers to any of this. After endless discussions over many years, I don't think anyone else does either.