11.15 Oxygen

Question 1

According to EU-OPS 1.760, what must a pressurised aircraft carry above 25,000 ft when cabin crew are required?

A. Extra fuel
B. Undiluted oxygen for certain passengers
C. Medical kits

Answer 1

B. Undiluted oxygen for certain passengers

Question 2

What is the cabin altitude maintained at during normal cruising flight?
A. 7620 m
B. 2440 m
C. 4300 m

Answer 2

B. 2440 m (8000ft)

Question 3

At what cabin altitude does the passenger oxygen system activate automatically?
A. 2500 m
B. 8000 ft
C. 4300 m

Answer 3

C. 4300 m (14000ft)

Question 4

What percentage of air is nitrogen?
A. 78%
B. 21%
C. 1%

Answer 4

A. 78%

Question 5

Which symptom is associated with hypoxia?
A. Rash
B. Headache and fatigue
C. Blurred vision only

Answer 5

B. Headache and fatigue

Question 6

Why is aviator’s oxygen used instead of medical oxygen?
A. It has more oxygen
B. Medical oxygen contains moisture that can freeze
C. Aviator’s oxygen is cheaper

Answer 6

B. Medical oxygen contains moisture that can freeze.

Question 7

Why is technical oxygen never used on aircraft?
A. It is too expensive
B. It is contaminated
C. It smells bad

Answer 7

B. It is contaminated

Question 8

What is pure oxygen stored in?
A. Barrels
B. Low pressure cylinders
C. High pressure cylinders

Answer 8

C. High pressure cylinders

Question 9

What colour are pure oxygen cylinders?
A. Blue
B. Green
C. Red

Answer 9

B. Green

Question 10

What happens to oxygen pressure as altitude increases?
A. It stays the same
B. It increases
C. It decreases

Answer 10

C. It decreases

Question 11

What type of regulator is used in the flight crew oxygen system?
A. Flow limiter regulator
B. Diluter-demand regulator
C. Pulse regulator

Answer 11

B. Diluter-demand regulator

Question 12

What is used in an oxygen system?
A. PRV (Pressure Regulating Valve)
B. Check valve
C. Shuttle valve

Answer 12

A. PRV (Pressure Regulating Valve)

Question 13

Where are the oxygen bottles usually stored on an aircraft?
A. Flight deck and lavatory
B. Passenger cabin overhead bins
C. Cargo compartment or Main Equipment Centre (MEC)

Answer 13

C. Cargo compartment or Main Equipment Centre (MEC)

Question 14

What are newer lightweight oxygen bottles made of?
A. Carbon steel
B. Aluminium wrapped with Kevlar™
C. Titanium

Answer 14

B. Aluminium wrapped with Kevlar™

Question 15

What does the direct reading pressure gauge on an oxygen bottle show?
A. Bottle temperature
B. Remaining oxygen time
C. Actual bottle pressure

Answer 15

C. Actual bottle pressure

Question 16

How can you calculate how full an oxygen bottle is?
A. Compare temperature and pressure readings
B. Shake the bottle
C. Check colour of safety disc

Answer 16

A. Compare temperature and pressure readings

Question 17

At what pressure does the oxygen bottle safety disc typically rupture?
A. 1850 psi
B. 2400 psi
C. 2600 psi

Answer 17

C. 2600 psi

Question 18

What’s the purpose of an oxygen bottle safety disc?
A. Rupture when the oxygen bottle is empty
B. Rupture when pressure or temperature is too high
C. Rupture when cabin is depressurised

Answer 18

B. Rupture when pressure or temperature is too high

Question 19

What colour is the disc that ruptures if a bottle’s safety device activates?
A. Green
B. Red
C. Yellow

Answer 19

A. Green

Question 20

What component ensures overpressure protection and connects to the aircraft skin?
A. Shut-off valve
B. Overboard discharge line with burst disc
C. Thermal compensator

Answer 20

B. Overboard discharge line with burst disc

Question 21

What are the components found on an oxygen bottle?
A. Shut Off Valve, Thermal Compensator, Direct reading gauge, Overpressure burst disc
B. Check valve, Thermometer, Compressor
C. Shuttle valve, Thermal Compensator, Direct reading gauge, Underpressure burst disc

Answer 21

A. Shut Off Valve, Thermal Compensator, Direct reading gauge, Overpressure burst disc

Question 22

What backup system is available if the main flight deck oxygen system fails?
A. Hand pump
B. Portable oxygen bottle
C. Cabin oxygen supply

Answer 22

B. Portable oxygen bottle

Question 23

What are the two types of portable oxygen systems mentioned?
A. Smoke mask and chemical hood
B. Full-face and continuous-flow masks
C. Manual pump and compressor

Answer 23

B. Full-face and continuous-flow masks

Question 24

What is portable oxygen equipment used for?
A. Cleaning the aircraft
B. Emergency and first aid
C. Cabin ventilation

Answer 24

B. Emergency and first aid

Question 25

How should leaks in a continuous-flow oxygen system be detected? A. Use of water and soap B. Oxygen-safe leak check fluid C. Listening for hissing sounds

Answer 25

B. Oxygen-safe leak check fluid (Look for the formation of bubbles)

Question 26

How are smoke hoods stored? A. Loosely in the flight deck B. Vacuum packed in specific storage containers C. In the cargo compartment

Answer 26

B. Vacuum packed in specific storage containers

Question 27

How do you check the smoke hood serviceability? A. Serviceability indicator which reacts with humidity B. Visual inspection of the smoke hood C. Smell

Answer 27

A. Serviceability indicator which reacts with humidity

Question 28

What oxygen pressure must the cylinders read? A. At least 10 psi B. No more than 20 psi C. At least 50 psi

Answer 28

C. At least 50 psi

Question 29

What are the two types of oxygen regulators used on aircraft? A. Flow-demand and mixed-flow B. Continuous-flow and demand-flow C. Variable-flow and static-flow

Answer 29

B. Continuous-flow and demand-flow

Question 30

What does a continuous-flow regulator do? A. Supplies oxygen only when breathing in B. Maintains a steady flow of oxygen whether the user is inhaling or exhaling C. Provides high-pressure oxygen for high altitudes

Answer 30

B. Maintains a steady flow of oxygen whether the user is inhaling or exhaling

Question 31

What does a demand-flow regulator do? A. Stops oxygen flow unless exhaling B. Supplies oxygen only when inhaling C. Provides oxygen through chemical reactions

Answer 31

B. Supplies oxygen only when inhaling

Question 32

Who are demand-flow systems typically used by? A. Cabin crew and passengers B. Ground staff C. Flight crew

Answer 32

C. Flight crew

Question 33

Where are passenger oxygen masks stored on large aircraft? A. Behind the seats B. Overhead in the Passenger Service Units (PSUs) C. Under the floor panels

Answer 33

B. Overhead in the Passenger Service Units (PSUs)

Question 34

What type of flow do passenger cabin oxygen masks provide? A. Demand flow B. Continuous flow C. Pressure flow

Answer 34

B. Continuous flow

Question 35

How are cabin oxygen masks activated? A. By removing a pin on the flight deck B. Automatically when the aircraft depressurises C. By pressing a button on the passenger panel

Answer 35

B. Automatically when the aircraft depressurises

Question 36

How many passenger masks are typically available per seat row? A. One per seat B. One per seat plus one extra C. One for every two seats

Answer 36

B. One per seat plus one extra

Question 37

What tool is used to open a single PSU box for maintenance without triggering the whole system? A. Mask tester B. Restraint/release tool C. Oxygen pin key

Answer 37

B. Restraint/release tool

Question 38

What are the two types of oxygen supply systems for passengers? A. Liquid and solid B. Manual and automatic C. Chemical and gaseous

Answer 38

C. Chemical and gaseous

Question 39

What are the two types of chemical oxygen systems? A. Portable and fully integrated B. Emergency and routine C. Pressurised and non-pressurised

Answer 39

A. Portable and fully integrated

Question 40

What chemical is used in the oxygen generator of a chemical system? A. Potassium chloride B. Sodium chlorate (NaClO₂) C. Calcium oxide

Answer 40

B. Sodium chlorate (NaClO₂)

Question 41

What triggers the chemical reaction in the oxygen generator? A. Flight crew switch B. Pulling the mask lanyard C. Increase in cabin humidity

Answer 41

B. Pulling the mask lanyard

Question 42

What initiates the high-temperature decomposition of sodium chlorate? A. Contact with water B. Striker igniting iron powder C. Battery-powered ignition

Answer 42

B. Striker igniting iron powder

Question 43

Once activated, how long does a chemical oxygen generator typically produce oxygen? A. 2–5 minutes B. 10–20 minutes C. 30–45 minutes

Answer 43

B. 10–20 minutes

Question 44

Can a chemical oxygen generator be turned off once activated? A. Yes, with a manual override B. No, it burns until it’s spent C. Only from the flight deck

Answer 44

B. No, it burns until it’s spent

Question 45

What visible indicator might show a chemical generator has been used? A. Melted outer case B. Change in mask colour C. Colour change indicator on the side

Answer 45

C. Colour change indicator on the side

Question 46

In the gaseous oxygen system, what opens the stowage box door? A. Electrical trigger B. Solenoid triggered by oxygen pressure C. Pulling the mask

Answer 46

B. Solenoid triggered by oxygen pressure

Question 47

In a gaseous system, when does oxygen start flowing to the passenger mask? A. Immediately after depressurisation B. When the system is armed C. When a mask is pulled and the lanyard tightens

Answer 47

C. When a mask is pulled and the lanyard tightens

Question 48

What does the flow control unit (FCU) do in a gaseous system? A. Filters the oxygen B. Raises oxygen pressure C. Reduces oxygen pressure to usable levels

Answer 48

C. Reduces oxygen pressure to usable levels

Question 49

What allows rebreather masks to reduce oxygen waste? A. Filters in the mask B. Sealed chambers that trap all air C. A bag that captures exhaled oxygen to be reused for the next breath

Answer 49

C. A bag that captures exhaled oxygen to be reused for the next breath

Question 50

What happens to the oxygen in a continuous flow mask when the user is exhaling? A. It stops flowing B. It is stored in a reservoir or escapes through vents C. It builds up pressure in the system

Answer 50

B. It is stored in a reservoir or escapes through vents

Question 51

What components make up a flight crew full-face oxygen mask? A. Nose cup, regulator, heater B. Harness, face piece, diluter-demand regulator, microphone C. Seal ring, filter, tubing

Answer 51

B. Harness, face piece, diluter-demand regulator, microphone

Question 52

What is the purpose of a blowout disc in an oxygen system? A. To store emergency oxygen B. To release excess pressure safely C. To filter oxygen before use

Answer 52

B. To release excess pressure safely

Question 53

Where is the blowout disc typically located on an aircraft? A. Inside the flight deck B. On the oxygen bottle C. On the fuselage skin

Answer 53

C. On the fuselage skin

Question 54

What is the function of a flow indicator in an oxygen system? A. Controls how oxygen is delivered B. Indicates oxygen flow is occurring C. Measures pressure loss in the regulator

Answer 54

B. Indicates oxygen flow is occurring

Question 55

How do most flow indicators work? A. They beep when flow stops B. They are activated manually C. A small object moves when oxygen flows

Answer 55

C. A small object moves when oxygen flows

Question 56

Why might flight crew on smaller aircraft use a pulse oximeter? A. To log flight hours B. To adjust oxygen flow and prevent hypoxia C. To check their hydration level

Answer 56

B. To adjust oxygen flow and prevent hypoxia