Reference: Regulation (EU) No 965/2012 on Air Operations, Annex I (Definitions) and Annex III (Part ORO)
The term 'Sterile Flight Deck' is used to describe any period of time when the flight crew members shall not be disturbed e.g. by cabin crew, except for matters critical to the safe operation of the aircraft and/or the safety of the occupants. In addition, during these periods of time the flight crew members should focus on their essential operational activities without being disturbed by non-flight related matters, i.e. flight crew members should avoid non-essential conversations, should not make non-safety related announcements towards the passengers, etc.
Sterile flight deck procedures are meant to increase the flight crew members' attention to their essential operational activities when their focused alert is needed, i.e. during critical phases of flight (take-off and landing, etc.), during taxiing and below 10 000 feet (except for cruise flight).
The Agency issued draft rules addressing sterile flight deck procedures in June 2013 (Opinion 05/2013) to the European Commission. Once adopted, these rules will be incorporated in the Regulation on Air Operations. The Agency expects that the sterile flight deck procedures will be in place in 2014.