IRImplementing rule
CAT.IDE.A.235Supplemental oxygen – pressurised aeroplanes
(a)Pressurised aeroplanes operated at pressure altitudes above 10 000 ft shall be equipped with supplemental oxygen equipment that is capable of storing and dispensing the oxygen supplies in accordance with Table 1.
(b)Pressurised aeroplanes operated at pressure altitudes above 25 000 ft shall be equipped with:
(1)quick donning types of masks for flight crew members;
(2)sufficient spare outlets and masks or portable oxygen units with masks distributed evenly throughout the passenger compartment, to ensure immediate availability of oxygen for use by each required cabin crew member;
(3)an oxygen dispensing unit connected to oxygen supply terminals immediately available to each cabin crew member, additional crew member and occupants of passenger seats, wherever seated; and
(4)a device to provide a warning indication to the flight crew of any loss of pressurisation.
(c)In the case of pressurised aeroplanes first issued with an individual CofA after 8 November 1998 and operated at pressure altitudes above 25 000 ft, or operated at pressure altitudes at, or below 25 000 ft under conditions that would not allow them to descend safely to 13 000 ft within four minutes, the individual oxygen dispensing units referred to in (b)(3) shall be automatically deployable.
(d)The total number of dispensing units and outlets referred to in (b)(3) and (c) shall exceed the number of seats by at least 10 %. The extra units shall be evenly distributed throughout the passenger compartment.
(e)Notwithstanding (a), the oxygen supply requirements for cabin crew member(s), additional crew member(s) and passenger(s), in the case of aeroplanes not certified to fly at altitudes above 25 000 ft, may be reduced to the entire flying time between 10 000 ft and 13 000 ft cabin pressure altitudes for all required cabin crew members and for at least 10 % of the passengers if, at all points along the route to be flown, the aeroplane is able to descend safely within four minutes to a cabin pressure altitude of 13 000 ft.
(f)The required minimum supply in Table 1, row 1 item (b)(1) and row 2, shall cover the quantity of oxygen necessary for a constant rate of descent from the aeroplane’s maximum certified operating altitude to 10 000 ft in 10 minutes and followed by 20 minutes at 10 000 ft.
(g)The required minimum supply in Table 1, row 1 item 1(b)(2), shall cover the quantity of oxygen necessary for a constant rate of descent from the aeroplane’s maximum certified operating altitude to 10 000 ft in 10 minutes followed by 110 minutes at 10 000 ft.
(h)The required minimum supply in Table 1, row 3, shall cover the quantity of oxygen necessary for a constant rate of descent from the aeroplane’s maximum certified operating altitude to 15 000 ft in 10 minutes.
Table 1 Oxygen minimum requirements for pressurised aeroplanes
| Supply for | Duration and cabin pressure altitude |
|---|---|
| 1. Occupants of flight crew compartment seats on flight crew compartment duty | (a) The entire flying time when the cabin pressure altitude exceeds 13 000 ft. (b) The remainder of the flying time when the cabin pressure altitude exceeds 10 000 ft but does not exceed 13 000 ft, after the initial 30 minutes at these altitudes, but in no case less than: (1) 30 minutes’ supply for aeroplanes certified to fly at altitudes not exceeding 25 000 ft; and (2) 2 hours’ supply for aeroplanes certified to fly at altitudes of more than 25 000 ft. |
| 2. Required cabin crew members | (a) The entire flying time when the cabin pressure altitude exceeds 13 000 ft, but not less than 30 minutes’ supply. (b) The remainder of the flying time when the cabin pressure altitude exceeds 10 000 ft but does not exceed 13 000 ft, after the initial 30 minutes at these altitudes. |
| 3. 100 % of passengers(1) | The entire flying time when the cabin pressure altitude exceeds 15 000 ft, but in no case less than 10 minutes’ supply. |
| 4. 30 % of passengers(1) | The entire flying time when the cabin pressure altitude exceeds 14 000 ft but does not exceed 15 000 ft. |
| 5. 10 % of passengers(1) | The remainder of the flying time when the cabin pressure altitude exceeds 10 000 ft but does not exceed 14 000 ft, after the initial 30 minutes at these altitudes. |
| (1) Passenger numbers in Table 1 refer to passengers actually carried on board, including persons younger than 24 months. | |
IR · CAT.IDE.A.235 — Regulation (EU) No 965/2012 · Air OPS Easy Access Rules · EAR revision 27 Mar 2026