During all phases of flight each flight crew member required to be on flight deck duty shall remain alert. If a lack
of alertness is encountered, appropriate countermeasures shall be used. If unexpected fatigue is experienced a controlled
rest procedure, organised by the commander, can be used if workload permits. Controlled rest taken in
this way may never be considered to be part of a rest period for purposes of calculating flight time limitations nor
used to justify any duty period.
I guess that's what you are referring to. Thank you very much! Just one more question - and please excuse my ignorance here - is EU-OPS already in force?