11.15 Oxygen Flashcards
The international standard atmosphere is measured at what temperature and at what pressure
Temperature: 15 degrees Celsius
Pressure: 1013.25 hectopascal
What gasses does air consist of
Nitrogen: 78%
Oxygen: 21%
Other inert gasses:1%
At what altitude is the amount of usable oxygen in air halved
18,000ft and quartered by 33,000ft
A what altitude would a person be in the zone of incomplete compensation
Between 15,000-20,000ft
What type of oxygen is used on aircraft
Aviators breathing oxygen as it is very dry
What two types of oxygen should never be used on aircraft
- Medical oxygen as it contains water droplets and would freeze
- Technical oxygen as it is contaminated
What type of tools must be used when working with oxygen
Clean and oil free to prevent explosion
At 21’degrees c what is the maximum pressure of an oxygen bottle
3200psi
How much pressure is stored in crew oxygen bottles
1850psi
What protection device is on an oxygen bottle to prevent overpressure
An overpressure disk
How do you work out how full an oxygen bottle is
By knowing the pressure and temperature and referring to a chart which is usually kept near the bottles
What pressure or below must an oxygen bottle not be filled and why
50psi as moisture could have gathered in the bottle
What is used to prevent the danger of heat concentration on oxygen ports when topping up with oxygen
A thermal compensator
What must not be disconnected on oxygen refill poets as you would have to replace the whole component
The thermal compensator B-nuts
How is oxygen transferred to the cockpit and cabin
Through lines and manifolds
As there are usually many bottles how does it show on the cockpit as a total pressure
The average pressure is converted by the voltage averaging unit
What Indicates that oxygen is flowing for the pilots and first officers emergency mask
A flow indicator is located on top of the box which it is stowed in and it blinks when there is oxygen flow
How long should the flight crew take to put on their oxygen mask
They should be able to do it with one hand in less than 5 seconds
What does a mask consist of
- A harness
- A face piece
- A diluter and demand regulator
- A microphone
What three functions does the Diluter demand regulator have
- Normal
- 100% Oxygen
- Emergancy
If cabin altitude reaches what altitude does the oxygen masks deploy automatically
14,000ft
How many oxygen masks are there per row
Always one more than there are seats, in case children are sharing with adults
What usually activates the deployment of the oxygen masks
A pressure switch in the pressurised area. There is also a manual switch in the cockpit
If oxygen masks have been deployed how must they be repacked
They must be re packed manually
What is the two ways that oxygen can be supplied by the masks
- Chemical system
- Gaseous system
In the chemical oxygen system what are the stowage boxes normally called
Emergency Oxygen Containers (EOC)
What does an EOC contain
A mask and a chemical generator which produces oxygen
What triggers the chemical reaction in the EOC bottles
A striker is pulled when the mask is tightened
What chemical is the oxygen generator filled with
Sodium chlorate
At what temperature does the chemical reaction happen in the oxygen generators
Around 350 degrees c
How long does an active oxygen generator generate oxygen for
Between 12-15 mins
In the gaseous system what are the stowage containers called
Passenger Service Units (PSU)
What are the 4 main purposes on the oxygen flow control unit
- Provide a flow shut off function
- The activate system
- the create the pressure to push the PSU doors
- They reduce the intermediate oxygen pressure to an adequate level for breathing
What are the portable oxygen bottles intended for
Emergency or first aid
What is the capacity and pressure of the portable oxygen bottles
Capacity - 11 cubic feet
Pressure - 1800 PSI
What is the purpose of the smoke hoods on the portable oxygen bottles
To protect the eyes and respiratory system. They are used when fighting a fire to prevent breathing in noxious gasses
