IRImplementing rule
CS 23.2320Occupant physical environment
(a)The applicant must design the aeroplane to:
(1)allow clear communication between the flight crew and passengers;
(2)protect the pilot against serious injury due to hazards originating from high energy, associated with systems and equipment; and
(3)protect the occupants from serious injury due to breakage of windshields, windows, and canopies.
(b)For Level-4 aeroplanes, each windshield and its supporting structure directly in front of the pilot must withstand, without penetration, the impact equivalent to a two-pound bird when the velocity of the aeroplane is equal to the aeroplane’s maximum approach flap speed.
(c)The aeroplane must provide each occupant with air at a breathable pressure, free of hazardous concentrations of gases, vapours and smoke during normal operations and likely failures.
(d)If a pressurisation system is installed in the aeroplane, it must be designed to protect against:
(1)decompression to an unsafe level; and
(2)excessive differential pressure.
(e)If an oxygen system is installed in the aeroplane, it must:
(1)effectively provide oxygen to each user to prevent the effects of hypoxia; and
(2)be free from hazards in itself, in its method of operation, and its effect upon other components.
IR · CS 23.2320 — CS-23 · ED Decision 2017/013/R · CS-23 Easy Access Rules · EAR revision 13 May 2026