Fathom, I think you're missing my point.
I didn't say crew are signing on fatigued. I said "under-rested". By which I mean they ensure they have not had had 8 hours continuous sleep prior to sign on. Purposefully.
Under a normal circadian rhythm, one sleeps 8 hours per day, and wakes for the remaining 16 hours.
If you sleep for 8 hours, and then try to take a two hour nap 4-8 hours later, you are unlikely to gain any sleep.
If one was to sleep 8 hours prior to signon for an 18 hour flight, the circadian rhythm will dictate that it's bed-time in the last few hours of the flight. That's the last thing you want if you have been unable to sleep inflight. Add jet-lag to the equation and it gets worse.
Hence, turn up either after a short sleep (2-4 hours), or after a considerable wake period, and you stand a chance of actually sleeping in the bunk and being alert for the duration of the flight, and, most importantly, the arrival.
This is not news. ULH pilots have been doing this for years. You are obviously not one.
My question in the context of the thread was whether FRMS takes into account that the majority of ULH pilots have learned by experience that this is the best way to operate. I doubt it.
And so, I put to the community that commuting to an ULH flight may not necessarily be the threat that it is being made out to be. A couple of hours of shuteye on an A330 might actually be ideal from an FRMS perspective for the forthcoming 18-20 hour duty.
Last edited by Derfred; 10th Jan 2017 at 14:22.