CHAPTER 35

Question 1

How can the passenger oxygen masks be deployed?

Answer 1

The masks fall automatically when the cabin altitude is higher than 14,000 feet or manually when a crew member pushes the MASK
MANual ON pushbutton.

Question 2

When the passenger oxygen system is deployed what indication is presented to the flight crew?

Answer 2

The passenger SYStem ON indicator light (21VU) comes on white when the passenger oxygen system is electrically supplied.

Question 3

When the passenger oxygen system is deployed what else happens in the cabin?

Answer 3

A taped message is transmitted on the passenger address system.

Question 4

What indication is there for an overpressure of the flight crew oxygen system?

Answer 4

Rupture of the frangible disk is set at a cylinder pressure of 2500 to 2775psi. An overboard green discharge indicator is connected to the
high-pressure safety outlet, if there is overpressure, the green disk blows out and a yellow indicator comes into view to show that the cylinder was discharged or the pressure relief valve is open.