RAT 5. There are always buts in everything. 4 on 4 off is a very social roster and always popular with those who can get on to it. But it can be very expensive for the company. To find out whether it can work you have to overlay it against the actual workload requirement. It starts to fall down if there are daily differences or differences across the day. For example Gatwick has a huge long haul arrivals and departure peak in the morning. If you overlay a 4 on 4 off roster against that you get inefficiencies. So what you do is overlap it with a 5/3 or with part-time staff.
The sysytem with which I got entangled was based on staff declaring preferences. The fear was that some staff would not want to work what were thought to be unpopular routes. In practice it was easy to meet all preferences. There are plenty of people who want to work weekends, for example. There are others who do not funcrtiom well at the end of the day but are very happy with early starts.
What I would say needs to happen is to create a shared objective along the lines rovemnets etc. with open minds. No time limit to discussuions.""Of course the pilots want to see the company doing well. But the pilots want a working environment that enables them to work at their best and have a civilised life. Conflicts serve no good so let us talk about changes, experiments, improvemnets etc."
I fully recognise that open minds can be hard to achieve but when you do get to that state it can be very rewarding. But it can never be done against the clock.