I'm only speculating, sorry, as someone who's spent a lot of time on planes.
...but I've observed a fairly obvious system of attempting to regulate sleeping patterns on planes independent of outside time. Setting a slightly unnatural 'pattern' to a flight with timed refreshments, meals, sleepy time etc. Presumably to provide a sense of 'natural' sleep/wake cycles and also to manage the cargo so the flight crew can also rest as required.
The blinding light on the horizon coming in full bore at right angles, when passengers are supposed to be sleeping is probably an issue, but I suspect that having the blinds drawn even when dark is a psychological 'it's sleepy time, so sleep... so the crew can chill out too' is another thing.
That seems like a good explanation. My circadian rhythms are shot with a decade of all nighters and free wheeling around the clock so I might not be as sensitive to these techniques :-)
...but I've observed a fairly obvious system of attempting to regulate sleeping patterns on planes independent of outside time. Setting a slightly unnatural 'pattern' to a flight with timed refreshments, meals, sleepy time etc. Presumably to provide a sense of 'natural' sleep/wake cycles and also to manage the cargo so the flight crew can also rest as required.
The blinding light on the horizon coming in full bore at right angles, when passengers are supposed to be sleeping is probably an issue, but I suspect that having the blinds drawn even when dark is a psychological 'it's sleepy time, so sleep... so the crew can chill out too' is another thing.