8.8 OXYGEN REQUIREMENTS

The altitude at which an aircraft is designed to maintain a comfortable cabin pressure, even when flying at higher altitudes.

Supplemental oxygen is required for flight crew members when the cabin pressure altitude (the altitude they feel inside the cabin) exceeds 10,000 feet.

Flight crew members must have an oxygen mask readily available at their duty station while flying above 25,000 feet.

Flight crew must have enough oxygen to cover the entire flight time when the cabin pressure altitude exceeds 13,000 feet.

Flight crew must have enough oxygen to cover the entire flight time when the cabin pressure altitude exceeds 10,000 feet but does not exceed 13,000 feet after the first 30 minutes.

The minimum oxygen supply required for aircraft certificated to fly at altitudes greater than 25,000 feet is two hours.

The oxygen supply provided must be sufficient for a constant rate of descent from the aircraft's maximum certificated operating altitude to 10,000 feet in 10 minutes followed by 110 minutes at 10,000 feet.

Flight crew members performing essential duties must use supplemental oxygen continuously after 30 minutes when the cabin pressure altitude exceeds 10,000 feet and at all times when the cabin pressure altitude exceeds 13,000 feet.

The dispensing units for supplemental oxygen must be evenly distributed throughout the Personnel Accommodation area of the aircraft, with 10% more units than the number of seats.

Above 25,000 ft, every person onboard needs a dispensing unit connected to the oxygen supply. This includes additional crew members who are not part of the flight crew.

The oxygen supply is designed to provide enough oxygen for 100% of the passengers for the entire flight, or for 10 minutes, whichever is greater.

For every 100 people on the plane, 30 of them need to have enough oxygen for the entire flight when the cabin pressure altitude is between 14,000 ft and 15,000 ft.

When the cabin pressure altitude is above 10,000 ft but below 14,000 ft, 10% of the passengers need enough oxygen for the entire flight. However, the oxygen supply only needs to be available after the first 30 minutes at these altitudes.

If the aircraft is designed to fly above 25,000 ft, a supply of undiluted first aid oxygen must be available for passengers who might need it due to medical needs.

First aid oxygen is for those who need undiluted oxygen after the supplemental oxygen has been used up.

The oxygen supply for first aid must be enough for 2% of the passengers for the entire flight. However, it must be at least enough for one person.

The amount of portable first aid oxygen on board an aircraft is enough to support 2% of passengers in case of a cabin pressure failure at an altitude between 8,000 ft and 15,000 ft.

The crew protective breathing equipment (PBE) must not obstruct communication. This means it shouldn't hinder the ability of the crew to speak and hear clearly while wearing it.

Each member of the flight crew on duty must have equipment to shield their eyes, nose, and mouth, and provide oxygen for at least 15 minutes.

Besides the supplemental oxygen system, a separate portable protective breathing apparatus for one crew member must be available on the flight deck. This device provides breathing gas for at least 15 minutes and can be quickly accessed by any crew member in their assigned area.

The term 'persons onboard' refers to passengers and crew members. However, it excludes the operating crew which is defined separately in the Operations Manual Part A, Section 1.