The Air Navigation Order 1995

Scale L2

A supply of oxygen and the associated equipment to meet the requirements set out in Parts I and II. The duration for the purposes of this Scale shall be:

(i) that calculated in accordance with the operations manual prior to the commencement of the flight, being the period or periods which it is reasonably anticipated that the aircraft will be flown in the circumstances of the intended flight at a height where the said requirements apply and in calculating the said duration account shall be taken of:

(a) in the case of pressurised aircraft, the possibility of depressurisation when flying above flight level 100;

(b) the possibility of failure of one or more of the aircraft engines;

(c) restrictions due to required minimum safe altitude;

(d) fuel requirement; and

(e) the performance of the aircraft; or

(ii) the period or periods during which the aircraft is actually flown in the circumstances specified in the said Parts;

whichever is the greater.