What kinds of pressurization systems are there?
Where are they used and which one is most popular?
Isobaric – Preset and remains so. Most popular type.
Isobaric Differential – Military Use.
Sealed Cabin – Used only for spacecraft that carry their own gases to pressurize.
If Decompression occurs you should …… (6)
- Put on mask within 5 seconds or less
- Make sure it’s flowing 100%
- Maintain control
- Descend
- Land the aircraft as soon as possible/practical
- Seek Medical help if needed
How can you tell if decompression occurs?
- Fog
- Flying debris moves towards opening
- Sound (can be hiss to a loud bang)
- Cooler temperatures
Advantages of pressurization (4)
Oxygen mask not needed usually
Less noise
Less decompression sickness
Fewer trapped gas problems
Disadvantages of Pressurization?
Chance of losing pressurization
What are the three types of decompression and how long does it take.
- Slow Decompression – Greater than ten seconds, most dangerous type since you may not be aware.
- Rapid Decompression – Total loss of pressurization between 1-10 seconds
- Explosive Decompression – Less than 1 second, happens faster than lungs can decompress.
Time is the main contributing factor with decompression but what are some other factors that effect decompression? (5)
- Size of the opening
- Volume of the cabin
- Pressure Differential – difference in pressure of ambient and inside cabin
- Pressure Ratio – compressors rate of air coming in dictates how pressure I lsot
- Altitude – greater altitude when occurs the more sever the physiological effects
Ways you can tell decompression is occuring (4)
- Fog (lowered vis)
- Flying debris moves towards opening
- Sound (can be hiss to a loud bang)
- Cooler temperatures
Physical Effects of Decompression
- Middle Ear, Sinuses, Digestrive Tract
- Decompression Sickness
- Hypothermia (at higher altitudes)
- Hypoxia
- Hyperventilation
What should you do if decompression occurs?
- Put on mask within 5 seconds or less
- Make sure it’s flowing 100%
- Maintain control
- Descend
- Land the aircraft as soon as possible/practical
- Seek Medical help if needed
How does pressurization work?
Air compressed and forced into the pressure capsule at a constant rate and OUTFLOW VALVES regulate pressure. There is an emergency outflow in the front of the plane.
Why should you fly high? WHy would you want to?! (7)
- Fuel economy
- Performance
- Above the weather
- Smooth air
- Fly high without supplemental if pressurized
- Prevent decompression sickness with pressurization
- Performance.
Inside the Pressurization Capsule is (4)
- cabin,
- flight compartment,
- cargo,
- underfloor.
Unpressurized areas of the aircraft are (3)
- Nose gear well
- Forward pressure bulkhead
- Normal outflow valve
What cabin altitude is desired for pressurization, why isn’t it possible?
The lowest you could possibly get, Sea level
Pressurization Differential is hard to maintain low enough to avoid bursting.
If you want differential pressure to go down, the ________ altitude must go up, which causes the pressure to go ________. (EXAM)
If you want differential pressure to go down then cabin altitude goes up which then pressure has to go DOWN.
Pressure Differential ( ON EXAM ) :
What is it?
How is it measured?
Structural strength depends on how much _______ the cabin can handle.
Normal pressure differential that is tolerable structurally is usually between ____ and ____ psi.
The higher the differential, the closer to ________ the system can maintain or the _____________.
- Pressure differential is the difference between cabin pressure and the atmospheric pressure.
- Measured in PSI
Structural strength depends on how much pressure differential the cabin can handle.
Normal pressure differential that is tolerable structurally is usually between 3.5 and 8 psi.
The higher the differential, the closer to sea level the system can maintain or the higher it can go.
The air pump feeds into the ________ and the _______ regulated the pressure.
The air pump feeds into the pressure capsule and the outflow valve regulated the pressure.
What is an outflow valve and what does it do.
• Vents cabin to outside (ambient) air
o Keeps cabin pressure constant
o Releases excess pressure into the atmosphere
Airflow in a cabin always flows ______ so you should definitely try to pick carefully where you sit in a plane.
Front to back
Negative pressure relief valve
Prevents ______ from exceeding cabin pressure.
Allows _______ outside to change cabin pressure.
It is a _________
Prevents ambient pressure from exceeding cabin pressure.
Allows ambient pressure outside to change cabin pressure.
It is a safety measure
Pressure safety release valve
Opens to prevent _________.
Just in case ______ fails.
Opens to prevent excessive differential
.
Just in case outflow valve fails.
How do you find out bursting force?
Cabin Altitude – Pressure outside =psi needed to survive
How does a pressurization system work?
- System maintains ambient pressure until passing 8,000 ft. then maintains 8,000 feet MSL in the climb.
- Once it reaches the max pressure differential it increases as outside pressure decrease, cabin pressure maintains constant. Cabin altitude changes to higher pressure setting so it can maintain within the max pressure differential.
*Cabin pressure gets higher as ou continue your climb past the max differential so that it never exceeds.
As climb continues cabin pressure slowly decreases (differential control) to prevent exceedni the max differential.
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Block 134
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Block 1 Exam20
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Block 29
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Airfoils7
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Induction13
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Turbo Charging6
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COMMERCIAL MANEUVERS0
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Aerodynamics Block 1540
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Electricity 32430
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Hydraulic Systems21
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Landing Gear8
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Glossary Terms26
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323- GROUND EFFECT4
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323 - Thrust, Climb Performance, Takeoff Performance16
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324 Air Conditioning26
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Takeoff, Climb, Cruise 32328
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High Altitude Physiology 32424
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Pressurization25
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Landing 32327
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324 FARS16
