The purpose of Subpart-FTL is to ensure that crew members in commercial air transport operations are able to operate with an adequate level of alertness. It does not regulate the activities performed by crew members in their free time.
Nonetheless, it is the responsibility of crew members to make optimal use of the rest periods and to be properly rested so they will not perform duties when unfit due to fatigue.
A crew member in commercial air transport operations may be required to report to the operator his/her professional flying activities outside the commercial air transport operation to allow the operator to discharge its responsibilities (ORO.FTL.110) appropriately.
An operator should establish its policy with regard to crew members conducting these kinds of activities.