AGK Systems - Cabin Conditioning And Pressurisation Flashcards
How do light single engine aircraft obtain hot air?
Risk?
Heat exchanger wrapped around the exhaust, mixed with cold air before entering cabin.
Heat exchanger leaking causing carbon monoxide poisoning.
How does air conditioning work on large transport aircraft?
Use bleed air to supply the air conditioning packs via the pneumatic system.
What are the 5 minimum requirements for large aircraft air conditioning?
Provide 1lb of air per seat per minute normally.
Provide 0.5lb of air per seat per minute following failure of one pack.
Control temperature within the range 18-24degrees.
Ensure that carbon monoxide is less than 1 part in 2000.
Humidity maintains around 30%.
Known as the environmental control system.
How does the bootstrap air conditioning operation work?
Bleed air compressed and passed through heat exchanger.
Partially cooled bleed air enters the turbine, it loses energy.
Mixed with hot bleed air (trim air) to provide air at just the right temperature.
Water extractor fitted just before the entry to the turbine.
The compressor is driven by the turbine.
Also know as air cycle machine arrangement.
Where is the greatest decrease in temperature during air condition operation?
Secondary heat exchanger.
How does ram intake air condition work?
Combined compressor and turbine section know as cold air unit.
Ram air duct is equipped with a fan to draw the air through it when aircraft is stationary.
Volume of hot bleed air which bypasses cold air unit is regulated by the temperature control valve.
Entire pack is cooled by a pack cooling fan.
An example of air condition.
Bleed air flowing to the pack is regulated by the flow control valve.
One flow control valve is installed for each pack.
Normally closed isolation valve prevents air from left bleed system from reaching the right pack.
The bypass is connected to the temperature sensors which adjust the temperature control valve.
Explain the air distribution system.
Conditioned air flows through under floor pressure ducts.
It flows downwards and extracted at floor level by recirculation fans driven by AC electric motors.
50% is then recirculated after passing through the high efficiency particulate air HEPA filters. These trap up to 99% of bacteria and viruses.
What is the source of air for pressurising the aircraft’s hydraulic resivoir?
Bleed air. Pneumatic system.
