11.15 Oxygen

Question 1

At what altitude does the usable oxygen half?

Answer 1

18,000 feet (5480 m)

Question 2

What is the cabin altitude of aircraft when it is cruising?

Answer 2

8,000 feet

Question 3

How does lack of oxygen affect humans at :

a) 10,000 ft
b) 14,000 ft
c) 15,000 - 20,000 ft

Answer 3

a) faster breaths to compensate for lack of oxygen
b) exhaustion and sleepiness
c) loss of concentration, partial memory loss, muscle ache, loss of judgement

Question 4

Why is oxygen used on aircraft different to others used on the ground?

Answer 4

Aviators breathing oxygen is dry, moisture in normal oxygen would freeze

Question 5

What is important about tooling when working on oxygen systems?

Answer 5

Must be clean and oil free

Question 6

What does the crew oxygen system supply to?

Answer 6

Cockpit crew only

Question 7

Where are oxygen bottles stored?

Answer 7

Lower deck

Question 8

What are the typical materials that oxygen bottles are made of?

Answer 8

Steel alloy or Kevlar (composite)

Question 9

What colour are oxygen bottles on aircraft?

Answer 9

Dark Green

Question 10

At 21 degrees C what is the maximum capacity of an oxygen bottle?

Answer 10

3200

Question 11

Where can the actual bottle pressure be found?

Answer 11

Direct reading pressure gauge

Question 12

What information would you need to determine how full the bottle is? [2]

Answer 12

• Actual bottle pressure and temperature

- Referral to chart

Question 13

Where would an over pressure indication be found?

Answer 13

Near the oxygen filler port

Question 14

How are the lengths of high pressure lines reduced in an oxygen system?

Answer 14

Pressure regulator located near the oxygen bottle

Question 15

When does the oxygen begin to flow in crew oxygen masks?

Answer 15

When the mask is removed from the storage box

Question 16

What does the crew mask consist of? [4]

Answer 16

• Harness
• Face piece
• Diluter demand regulator
• Microphone

Question 17

What are the 3 operating modes of the diluter demand regulator?

Answer 17

• Normal
• 100% oxygen
• Emergency

Question 18

At what altitude will passenger oxygen masks deploy automatically?

Answer 18

14,000ft

Question 19

What are the 2 ways oxygen is supplied to the system?

Answer 19

• Chemical system

- Gaseous system

Question 20

What does a thermal compensator do?

Answer 20

Distributes the heat that may occur during recharging

Question 21

What does a pressure reducer do?

Answer 21

Reduces the pressures leaving the bottle to an intermediate pressure

Question 22

If there are more than 1 oxygen bottle, what happens to the indications on the flight deck?

Answer 22

The pressure is averaged between the bottle by a voltage averaging unit

Question 23

How can the pilots oxygen masks be tested?

Answer 23

Press to test and reset lever without taking the mask out of the stowage box

Question 24

Where are the passenger oxygen masks located?

Answer 24

The passenger service units

Question 25

How is the passenger oxygen system activated? (2)

Answer 25

- automatically by pressure switch | - manual on flight deck if pressure switch fails

Question 26

What can be used for maintenance to open a single PSU containing the passenger oxygen masks without activating the whole system?

Answer 26

A special tool

Question 27

How does the chemical supply system operate?

Answer 27

The doors operate electrically, dropping masks, oxygen will only flow when the masks are pulled where the oxygen generation process starts

Question 28

What happens when the pin pulled from the oxygen generator?

Answer 28

Striker triggers a chemical thermal reaction inside the generator

Question 29

What is the oxygen generator filled with?

Answer 29

Sodium chlorate

Question 30

How is oxygen generated?

Answer 30

High temperature decomposition of sodium chlorate

Question 31

How does an oxygen generator indicate that it has been used?

Answer 31

Heat generated changes the colour of the indicator on the side of the bottle

Question 32

In a gaseous supply system, where is the oxygen supplied from?

Answer 32

oxygen bottles, similar to those used in the crew system

Question 33

In the gaseous oxygen system, what does a flow control unit do? (4)

Answer 33

- provide a shut off function when not in use - activate the system - produce the pressure push to open the PSU’s - reduce the intermediate oxygen pressure to an adequate level for breathing

Question 34

What is used to transport the pressure push?

Answer 34

Ring line

Question 35

How do the PSU’s open?

Answer 35

High pressure oxygen flows for a few seconds moving the diaphragm and moving a plunger downwards. This moves the latch plate and hooks to the left, Opening the door

Question 36

What need to be done before oxygen will flow to the masks?

Answer 36

They need to be pulled and tightened by at least one lanyard, pulling a pin

Question 37

Other than crew and passenger oxygen systems, what is the other type?

Answer 37

Portable oxygen system

Question 38

Where can portable oxygen equipment be located?

Answer 38

Flight deck and near exits in passenger compartments

Question 39

What is the intended use of a portable oxygen bottle?

Answer 39

For emergency and first aid use

Question 40

What is the maximum filling pressure of a portable oxygen bottle?

Answer 40

1800 psi

Question 41

What components does the cylinder head of the portable oxygen bottle consist of? (6)

Answer 41

- manual shut off valve - pressure gauge - frangible disk for over pressure relief - pressure regulator reducing oxygen pressure to suitable levels - built in relief valve In case pressure regulator fails - filling valve allows oxygen bottle to be filled

Question 42

What do smoke hoods provide protection against?

Answer 42

Eyes and respiratory system for crew, | Prevent inhalation of smoke and noxious gases

Question 43

What does the smoke hood consist of? (3)

Answer 43

- the hood itself - inner mask - oxygen generator

Question 44

What two types of masks are used with portable oxygen bottles?

Answer 44

- Full face smoke mask | - continuous flow oxygen masks (first aid purposes)