I once worked a shift pattern on 15 days on, 15 days off, getting airborne every 30 hours for a 10 hour flight. This did not break our maximum limit of 120 hours every month, but it was hard graft. It was the rolling 6 hours of jet-lag that hurt the most. I found the best way to handle things was to base my life around the next take-off time and adjust my sleep period by a commensurate 6 hour slip every ‘day’. Sometimes I had to fight to stay awake until bed-time, sometimes I had to use help to get to sleep.
After 6 months of this work pattern, there had been a number of instances of ‘near-misses’. Our management were well aware, but crews were in short supply and the task was essential. We were studied by some boffins from, I seem to recall, Farnborough. I found 2 of their tips to be valuable and work for me.
Firstly was to take power naps, but strictly limit them to either 20 minutes or more than 2 hours. It seems that anything between 20 minutes and 2 hours places you into the wrong type of sleep, and you run the risk of waking up feeling worse than having no sleep.
The other tip was not to be afraid of using hypnotics, such as temazepan, to trigger sleep. They clear your system so quickly that there is no residual effect, even if you have to get up straight away after taking them. This was put to the test by our nav, who dreamt that he could not sleep, got up and took a double dose to make sure, just as his alarm went off. No time to relax, nothing for the drug to work on, no side-effects.
Those on my crew that tried to maintain their normal sleep pattern were next to useless come the early hours.
The other point of interest was the control exercises that the boffins gave us to do after each flight. My performance dropped from finding the exercise easy to complete after the first flight of each cycle, to about 50% performance after the 3rd flight, to being unable to see a single answer from that point onwards. I felt fine but the practical demonstration of how much by mental reasoning was degraded was frightening.