The Air Navigation Order 1995

Pressurised aircraft

(i) When flying at or below flight level 100:

(ii) Nil.

(ii) When flying above flight level 100 but not exceeding flight level 250:

(a) Members of the flight crew	30 minutes or whenever the cabin pressure altitude exceeds 10,000 ft, whichever is the greater
(b) Cabin attendants and 10% of passengers	(aa) When the aircraft is capable of descending and continuing to its destination as specified at Aa hereunder, 30 minutes or whenever the cabin pressure altitude exceeds 10,000 ft, whichever is the greater (bb) When the aircraft is not so capable, whenever the cabin pressure altitute is greater than 10,000 ft, but does not exceed 12,000 ft
(c) Cabin attendants and passengers	(aa) When the aircraft is capable of descending and continuing to its destination as specified at Aa hereunder, no requirement other than that at (ii)(b)(aa) of this part of this scale (bb) When the aircraft is not so capable and the cabin pressure altitude exceeds 12,000 ft the duration shall be the period when the cabin pressure altitude exceeds 12,000 ft or 10 minutes, whichever is the greater

(iii) When flying above flight level 250:

Supply for	Duration
a A. The flying machine is capable, at the time when a failure to maintain cabin pressurisation occurs, of descending in accordance with the emergency descent procedure specified in the relevant flight manual and without flying below the minimum altitudes for safe flight specified in the operations manual relating to the aircraft, to flight level 120 within 5 minutes and of continuing at or below that flight level to its place of intended destination or any other place at which a safe landing can be made.
(a) Members of the flight crew	2 hours or whenever the cabin pressure altitude exceeds 10,000 ft, whichever is the greater
(b) Cabin attendants	Whenever the cabin pressure altitude exceeds 10,000 ft, and a portable supply for 15 minutes
(c) 10% of passengers	Whenever the cabin pressure altitude exceeds 10,000 ft but does not exceed 12,000 ft
(d) 30% of passengers	Whenever the cabin pressure altitude exceeds 12,000 ft but does not exceed 15,000 ft
(e) All passengers	If the cabin pressure altitude exceeds 15,000 ft, the duration shall be the period when the cabin pressure altitude exceeds 15,000 ft or 10 minutes, whichever is the greater
(f) 2% of passengers or 2 passengers, whichever is the greater, being a supply of first aid oxygen which must be available for simultaneous first aid treatement of 2% or 2 passengers wherever they are seated in the aircraft	Whenever, after decompression, the cabin pressure altitude exceeds 8000 ft