Very interesting & appropriate topic. I heard FAA were going to look into this with a view to some "rules". That was a year ago. Any news anyone?
At Cargolux, we have 16hrs in our contract. Obviously not always practical, so we get the job done, then go to the hotel (paid as overtime when applicable). It's an arrangement that works.
I for one am not a good sleeper on airplanes, not even when a bed is available. I have to be REALLY tired before I sleep. Even then, its not exactly restfull.
As an example, last year: I wanted to to observe the goings on at some of our stations so flew LUX/ZRH/BOM/HKG/BOM/ZRH/LUX 46 hours. I wasn't doing any W&B, just observing a station (guess which one!). I mananged to sleep from BOM back to ZRH.
Nothing in the JARs either, since the whole issue of Duty Hours is a hot potato (Subsection Q is a blank page!)
If you're overtired, you will make mistakes. Tell the Capt. of the condition you are in & have him/her double check your calculations, maybe even inspect the loading/locks together. There's no shame in that.
------------------
rgds Rat