Hi Mr Angry;
I wasn't talking about just a single airline. As far as I know, Flybe and easyJet do 4 sector days, and Virgin and BA do long haul bullets, don't they?
What I meant was to put observers on each of those flight decks for a couple of weeks following a crew's roster, not just a single afternoon 'jolly'.
This way might convey the cumulative fatigue/tiredness that we experience?