BT:
Night flights are part of the industry, agreed. However, it's the combinatiions that are the problem. After 2 night flights, or earlies for that matter, anything that causes sleep deprevation, there needs to be a recovery period of a normal sleep cycle. When there is a roster that includes continuous disruption to the sleep pattern it does not allow for the batteries to recharge. thus, during the last couple of days of a block of 6, you are below par. If blocks of 6 are really deemed necessary, and that's debateable, the last day should have the most sympathetic duty, not the worst. If not, then, at the end of the block, the days off are just for that recharge; not real quality time off at all.
For night flight blocks, they could be done in pairs, perhaps 2 nights, day off, 2 nights, 4 off. normal shift workers do 4 ON, 4 off. They claim it allows a pattern. I'm sure that is very individual. What is true, IMHO,is that a block of nights is easier in a good quiet hotel rather than at home.
I once did freight for a year. 5 consecutive nights, 2 days off, on & on. Not recommended for the over 30's. Pure young man's stuff.
I'm convinced that the annual productivity can be achieved in a better manner. In one airline, 18 years ago, there was a cap,of 700 hours. This was seasonal, so the summers were hard and the winters relaxed. The company made profit and generally the life style was acceptable. Later, after I'd left, this cap was removed and pilots could then do upto 900. That is nearly 3 months extra productivity. I don't believe the airline made more profit, but the crews' lives were wrecked. For what? More people pollution, and greater strain on the aviation system. certainly not more profit for the shareholders.