Oxygen system

Question 1

Where does the air for the OBOGS come from?

Answer 1

LHS P3 bleed air

Question 2

What are the pros of OBOGS?

Answer 2

• Negates carrying bulky LOX equipment
• Does not require replenishment
• Minimum maintenance

Question 3

What are the 5 functions of OBOGS?

Answer 3

• Provide both pilots with a source of breathable air at all altitudes
• Provide both pilots with 95% O2 conc. when selected to MAX
• Indicate that the air is flowing from the OBOGS to the pilot
• Provide both pilots with an increasing positive pressure supply to the mask
• Conduct a BIT procedure

Question 4

What stops moist air entering the zeolite matrix?

Answer 4

Water separator

Question 5

What does the zeolite matrix do?

Answer 5

The crystalline structure allows O2 through but traps molecules such as Nitrogen

Question 6

What can an OBOGS FAIL on the EICAS indicate?

Answer 6

• Low bleed air pressure upstream of the concentrator
• Low concentration of oxygen downstream of the concentrator
• Internal failure within the system

Question 7

What does an OBOGS TEMP on the EICAS indicate?

Answer 7

Ducting temperature exceeding 200 deg F

Question 8

What does white powder in the oxygen mask indicate?

Answer 8

A breakdown of the zeolite matrix

Question 9

What is atelectasis

Answer 9

Partial collapse or incomplete inflation of the lung.
Due to breathing enhanced concentrations of oxygen while receiving G along the z axis and wearing anti-G suits