Division (c) The crew member shall not perform duties on an aircraft:

when under the influence of F1a psychoactive substance or when unfit due to injury, fatigue, medication, sickness or other similar causes;

until a reasonable time period has elapsed after deep water diving or following blood donation;

if applicable medical requirements are not fulfilled;

if he/she is in any doubt of being able to accomplish his/her assigned duties; or

F2if the crew member knows or suspects that they are suffering from fatigue as referred to in Annex V, point 7.5 to Regulation (EU) No1139/2018 or feels otherwise unfit, to the extent that the flight might be endangered.