# Commission Regulation (EU) No 965/2012 of 5 October 2012 laying down technical requirements and administrative procedures related to air operations pursuant to Regulation (EC) No 216/2008 of the European Parliament and of the Council, Division (c): The crew member shall not perform duties on an aircraft:

Extent: E+W+S+N.I.

(1)when under the influence of a psychoactive substance or when unfit due to injury, fatigue, medication, sickness or other similar causes;
(2)until a reasonable time period has elapsed after deep water diving or following blood donation;
(3)if applicable medical requirements are not fulfilled;
(4)if he/she is in any doubt of being able to accomplish his/her assigned duties; or
(5)if 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.

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Source: https://www.legislation.gov.uk/eur/2012/965/annex/IV/division/subpart+a/division/section+1/division/catgenmpa100/division/c (the official version)
Page: https://openlegislation.uk/eu-regulation-2012-965/annex-IV/division-subpart+a/division-section+1/division-catgenmpa100/division-c
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.