A320 Oxygen Questions

At approximately what cabin altitude should the passenger oxygen masks drop?

• 10,000 feet (+100, - 500 ft)
• 12,500 feet (+ or - 500 ft)
• 14,000 feet (+0, - 500 ft)
• 15,000 feet.

Explanation: Passenger oxygen masks are set to drop once cabin pressure altitude exceeds 14,000 ft (16,000 ft if the HI ALT LANDING pushbutton is set ON) - the closest match among the choices to that 14,000 ft trigger altitude.

Oxygen - Fixed Oxygen System for Cabin (Description, Operation)

Approximately how long are the passenger oxygen generators able to produce oxygen?

• 15 minutes.
• 20 minutes.
• 25 minutes.
• 30 minutes.

Explanation: The mask receives pure oxygen under positive pressure for roughly 13 to 22 minutes depending on the specific chemical generator fitted, with 15 minutes being a commonly cited figure for this aircraft's generators.

Oxygen - Fixed Oxygen System for Cabin (Description, Operation)

Illumination of the SYS ON light is an indication that:

• The crew must depress the MASK MAN ON pb in order to deploy the masks.
• Electrical power has been sent to deploy the masks, either manually or automatically.
• The crew oxygen cylinder is empty.
• All of the passenger masks have deployed.

Explanation: The SYS ON light comes on white when the control for the oxygen mask doors is activated - meaning electrical power has been sent to deploy the masks, whether that was triggered manually (MASK MAN ON) or automatically (cabin altitude exceeding the trigger altitude).

Oxygen - Fixed Oxygen System for Cabin (Controls and Indicators, Overhead Panel)

What is the main difference between the crew and the passenger oxygen system?

• There is no difference: both are served by oxygen cylinders.
• Crew is supplied from an oxygen cylinder; passengers are supplied by chemical oxygen generators .
• Both the crew and passengers are supplied with oxygen from chemical oxygen generators.
• The crew has an oxygen bottle for an emergency back-up supply.

Explanation: The cockpit is supplied from a high-pressure oxygen cylinder with a pressure regulator, while the cabin (passengers and cabin crew) is supplied by chemical oxygen generators.

Oxygen - General (Description) / Fixed Oxygen System for Cockpit and Cabin

On which ECAM page could the flight crew check the exact pressure of the oxygen cylinder?

• The PRESS page.
• The DOORS page.
• The COND page.
• The STATUS page.

Explanation: The oxygen cylinder's exact pressure is shown on the ECAM DOOR/OXY page.

Oxygen - Fixed Oxygen System for Cockpit (Controls and Indicators, ECAM DOOR/OXY Page)

What is the purpose of the CREW SUPPLY push button?

• When selected to ON, it supplies oxygen to the Captain & F/O only (jumpseats are not supplied)
• When selected to ON, it allows the flow of low pressure oxygen to the crew’s masks.
• In case of low cylinder pressure it allows the crew to tap into the passenger oxygen system.

Explanation: With CREW SUPPLY selected ON, the solenoid valve opens and supplies low-pressure oxygen to the crew masks - this is the normal in-flight position.

Oxygen - Fixed Oxygen System for Cockpit (Controls and Indicators, Overhead Panel)

What will depressing the guarded MASK MAN ON pb accomplish?

• A signal is sent to the chemical oxygen generators to start the flow of oxygen to the masks.
• It manually sends a signal to open the oxygen mask doors.
• Both are correct.

Explanation: Depressing the guarded MASK MAN ON pushbutton manually opens the oxygen mask doors - it doesn't by itself start the chemical generators, since oxygen generation only begins once a passenger pulls a dropped mask toward the seat.

Oxygen - Fixed Oxygen System for Cabin (Controls and Indicators, Overhead Panel) / (Description, Operation)

What does an amber OXY on the ECAM Doors mean?

• The crew supply switch is turned off and/or oxygen pressure is less than 400 psi
• The crew supply switch is turned off
• Oxygen pressure is less than 650 psi.
• Oxygen pressure is less than 300 psi.

Explanation: The OXY indication on the ECAM Doors page turns amber if the CREW SUPPLY pushbutton is switched off, and/or if oxygen pressure drops below 400 PSI (or low oxygen pressure is otherwise detected) - either condition triggers it.

Oxygen - Fixed Oxygen System for Cockpit (Controls and Indicators, ECAM DOOR/OXY Page)