Okay Not a airline pilot merely a light business jet one but there is another factor that needs to be taken into consideration and which may or may not give another reason for pilots nodding off.
A few years ago I was flying a Seneca Twin at FL100 single pilot with the non pilot owner in the right seat.
The aircraft was on autopilot in nav mode. I was very aware of the droning of the engines which became almost hypnotic like and found that I was finding it very hard to stop my eyelids flickering next thing I knew was a sharp dig in the ribs as the owner thought I had died or something.
How much research has been done on whether it is pilots falling asleep due to fatigue or design faults out of their control ie sounds or flashing lights which have hypnotic effects on the pilots. Or even light effects on clouds or sea surfaces pulsing city lights at night etc?
Finally contamination in the cabin from contaminated air? It may be interesting to read this report as even low levels can cause extreme fatigue
USATODAY.com - Travel - News - Verdict expected soon on toxic air aboard jets
I am sure that sounds and lights at certain frequencies can have an effect and as such should absolve the pilots from guilt?
Pace