if there is scientifically valid modelling that says there is no negative health impact
And that is the problem. There is already deleterious metabolic and cognitive health outcomes for operating crew with their current regime. So whether this longer sector is unfavourable or favourable to crews, the underlying negative outcomes from operating long-haul are already there. Crew will either suffer more, or a little less - but there is no removal of the consequences of circadian disruption, sleep deprivation, poor nutritional sustenance etc. And the fact that this ‘research study’ does not follow the Bradford Hill criterial for causation - means it is really just a meaningless data collection that will (being paid research), show some likely ‘favourable outcomes’ I am sure. Particularly for the sample of ‘commercial customers’ that travelled in a premium cabin with horizontal rest.