Deviation from the applicable CS ORO.FTL.125 (c) (see also ARO.OPS.235): What does a deviation from the applicable CS mean or derogation from an implementing rule?
The flight time specification schemes of an individual operator (IFTSS) may differ from the applicable CS / IRs under strict conditions.
The operator has a number of steps to follow before implementing a deviation/derogation.
Additionally, the competent authority has a number of steps to follow before approving a deviating/derogating IFTSS.
All the steps are described in this Evaluation Form (link) developed by EASA to facilitate NAAs and operators in this process.