BoredCounter
In answer to your question, my contract states the following:
Your working hours will depend upon the relevant rostering agreements, which may be altered at anytime. EJ will do its best to ensure that all CC of a similar grade will be rostered for as near as possible the same opportunity over a 3 month period to work the same number and the same type of sectors. We will comply withg all applicable CAA regulations relating to hours worked and time off
Why do you want to know that?? Although the contract says they can be altered at any time it is evectively a change of contract and that needs to be agreed through the correct channels IMHO with my basic understanding of UK and EU employment laws