Oxygen

Question 1

Oxygen regulatory requirements for depressurisation procedures:

What cabin (ie passenger) oxygen supply must be available to protect the passengers in the event of depressurisation:

Above 15,000’ What percentage of pax?
Below 15,000’, at and above 14,000’? What percentage of pax?
Below 14,000’, at and above 10,000’? What percentage of pax?

Answer 1

Above 15,000: 100% of pax
Below 15,000’, at and above 14,000’? 30% of pax
Below 14,000’, at and above 10,000’? 10% of pax (although not required during the first 10 mins)

Ref: Route and Aerodrome Information Guide: Performance/H2.1 Regulations

Question 2

Cabin (passenger) Oxygen Availability:

What is the assumed cabin oxygen availability for the:

• A380 3-class?
• A380 2-class?

What pressure are the the oxygen cylinders are normally maintained at:

• A380 3-class?
• A380 2-class?

For the 3-class, a cabin oxygen pressure of (how much?) psi is sufficient to dispatch with up to (how many?) passengers?

For the 2-class, a cabin oxygen pressure of (how much?) psi is sufficient to dispatch with up to (how many?) passengers?

Answer 2

The A380 3-class and 2-class are the same for cabin oxygen availability.
The assumed cabin oxygen availability, even though its a gaseous oxygen system, its treated as equivalent to a 22 minute chemical oxygen system, in terms of depressurisation profile.

Both the 3-class and 2-class cabin oxygen cyclinders are normally maintained at 1850psi.

3-class: 1300 psi sufficient to dispatch with up to 552 pax, except for the North Himalayan Routes
2-class: 1350 psi sufficient to dispatch with up to 654 pax, except for the North Himalayan Routes.

Ref: Route and Aerodrome Information Guide: Performance/H2.2 Regulations

Question 3

Can a pressurised flight be operated up to FL250 if the flight crew oxygen system becomes inoperative or empty?

Answer 3

Yes.

Provided that portable oxygen bottles are readily available for each crew member on duty. Above FL250 the quick donning oxygen system must be fully serviceable. (Can the quick donning masks be connected to portable oxygen bottles??)

Ref: OM-A/8.8 Oxygen Requirements/ 8.8.1 Flight Crew

Question 4

At what cabin altitude must the flight crew (pilots) use oxygen?

Answer 4

The flight crew (pilots) shall use oxygen whenever the cabin altitude is above 10,000’

Ref: OM-A/8.8 Oxygen Requirements/8.8.1.2 Use of Flight Crew Oxygen in Flight.

Question 5

Carriage of supplemental oxygen for passengers (portable oxygen bottles). (Emirates Airline aircraft company policy):

A supply of what length of time is required for:

• 100% of the pax?
• 30% of the pax?
• 10% of the pax?

Answer 5

For 100% of the pax:
- 10 mins, or the entire flight time the CABIN PRESSURE altitude exceeed 15,000’, whichever is greater.

For 30% of the pax:
- The entire flight time when the CABIN PRESSURE ALTITUDE exceeds 14,000’, not does not exceed 15,000’.

For 10% of the pax:
- The entire flight time when the CABIN PRESSURE ALTITUDE exceeds 10,000’, but does not exceed 14,000’, after the first 30 minutes at these altitudes.

Ref: OM-A/8.8 Oxygen Requirements / 8.8.3 Passengers.

Question 6

Above what altitude must passengers use oxygen?

Answer 6

15,000’

Ref: OM-A/8.8 Oxygen requirements/

Question 7

In accordance with FAR 121.333, what are the requirements of the cockpit fixed oxygen?

Answer 7

The fixed oxygen bottle for the cockpit must provide enough oxygen to protect all crew members, with the N/100% selector set to N, after loss of cabin pressure, to fly:

• A descent from FL430 to FL100 with a constant descent rate, for 10 mins.
• A step at FL100 for 100 mins

Ref: FCOM/Limitations/Oxygen