Definitions

Reference: Regulation (EU) No 965/2012, Annex I Definitions

Annex I (Definitions) of the Regulation (EU) 965/2012 on air operations contains definitions for critical phases of flight for aeroplanes and helicopters:

“'Critical phases of flight' in the case of aeroplanes means the take-off run, the take-off flight path, the final approach, the missed approach, the landing, including the landing roll, and any other phases of flight as determined by the pilot-in-command or commander.

'Critical phases of flight' in the case of helicopters means taxiing, hovering, take-off, final approach, missed approach, the landing and any other phases of flight as determined by the pilot-in-command or commander.”

As one can see from these definitions, for helicopters taxiing is defined as a critical phase of flight, while for aeroplanes it is not. Rules for activities considered acceptable during critical phases of flight are provided in the Regulation (EU) No 965/2012 on air operations – in Annex III (Part-ORO), Annex IV (Part-CAT), Annex VI (Part-NCC), Annex VII (Part-NCO) and Annex VIII (Part-SPO). Basically, these implementing rules require crew members during critical phases of flight:

• to be seated at his/her assigned station; and
• not to perform any activities other than those required for the safe operation of the aircraft

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, landing, etc.), during taxiing and below 10 000 feet (except for cruise flight).

The sterile flight deck procedures were published in Regulation (EU) 2015/140 as an amending regulation to (EU) No 965/2012 on air operations. EASA published the associated AMC and GM with ED Decision 2015/005/R.

Reference: Regulation (EC) No 216/2008, Regulation (EU) No 965/2012

The term 'commercial operation' is now defined in Article 2 of Regulation (EU) No 965/2012 as follows (previously in Reg. (EC) No 216/2008):

“'Commercial operation' means any operation of an aircraft, in return for remuneration or other valuable consideration, which is available to the public or, when not made available to the public, which is performed under a contract between an operator and a customer, where the latter has no control over the operator.”

The term 'commercial air transport (CAT) operation' is defined in Article 3 of Regulation (EU) 2018/1139 as follows:

“'Commercial air transport' means an aircraft operation to transport passengers, cargo or mail for remuneration or other valuable consideration.”

The two definitions make it clear that 'commercial operations' include 'CAT operations'. Specialised operations (SPO) are another type of commercial operations. They are also defined in Article 2 of Reg. (EU) No 965/2012.