First-aid oxygen dispatch requirements
 

Good morning, aviators,



Has anyone ever calculated the minimum amount of first-aid oxygen required for dispatch (Portable Oxygen Dispensing Units) or know how to do it?

According to CAT.IDE.A.230 First-aid oxygen:

(b) The oxygen supply referred to in (a) shall be sufficient for the remainder of the flight after cabin depressurisation when the cabin altitude exceeds 8 000 ft but does not exceed 15 000 ft, for at least 2 % of the passengers carried, but in no case for less than one person.

(c) There shall be a sufficient number of dispensing units, but in no case less than two, with a means for cabin crew to use the supply.

AMC1 CAT.IDE.A.230 First-aid oxygen:

(b) The oxygen supply may be calculated by assuming an average flow rate of at least 3 litres standard temperature pressure dry (STPD)/minute/person, or equivalent, as demonstrated during the certification of the dispensing unit.



What is the minimum number of bottles required for dispatch if capacity of one bottle is 11.0 CU FT (311 Liters) and the total amount of passenger seats are 189?


Thank you in advance!

The A320 MEL has a helpful OPS procedure (35-30-01D) to calculate the required oxygen, based on quantity per bottle and amount of bottles. If there isn't enough O2 on board the passenger numbers may have to be reduced. 750l O2 is enough for 193 passengers, so would cover the 189. However, we do carry 202l bottles, so that procedure wouldn't help much on 311l ones.

Denti,

Thank you so much for your comment. I checked a few MELs for A320 and didn't find any OPS procedure for calculating the requred amount of oxygen. I suppose that this procedure that you are talking about is probably company procedure established by an operator. Could you be so kind to copy paste or make a screenshot of this procedure to see how it looks like.

Thank you in advance!