Pressurization

Question 1

Pressurization

Answer 1

it is the last step of the air, it is delivered in the cabin and manage with the open or close of the valve to regulate the request pressure

Question 2

Pressure cabin

Answer 2

It is the pressure tha is inside the cabin and need to be check in order to avoid possible healty problem.

Question 3

Cabin Altitude

Answer 3

is the pressure that we find in the cabin related with the altitude.

• cockpit max value is 8000’
• passenger 10000’

Question 4

Δ P

Answer 4

is the difference between the Pressur in the cabin and the Pressure outside the cabin, Different airplane can haave a different max Δ P.
Δ P = 0 Pc= Ps Unpressurizatied airplane
ΔP positive = Pc-Ps Pressuriziation
ΔP negative = if this happen inwards valve open
Max value of ΔP is +9 PSI for structural but normal operate range is around 8 PSI
Max ΔP negative is around -0.5/1 PSI

Question 5

system control

Answer 5

• Manualy
• Alternate(is for rendundancy, it is a kind of automatic)
• Automatic

Question 6

Intrument

Answer 6

3 indicator:
Δp
cabin altitude
cabin vertical speed indicator

Question 7

Valves

Answer 7

Inward valve - prevent engative Δp
Safety - act when the Δp is more than limit in positive
dumping - manualy activator, reduce the Cp to 0 in case of emergency decompressing

Question 8

Pressuration schedule

Answer 8

It is the plan of the pressuration during the flight, it is divided in:

• ground
• proportional control
• isobaric control

Question 9

Ground schedule

Answer 9

When the aircraft begins to taxi the pressurization GROUND/FLIGHT switch is selected to FLIGHT and the aircraft is pre-pressurized to Δ of 0.1 psi.

Question 10

Proportional controls chedule Climbing

Answer 10

The controller will PS and Pc will use the outflow valves to control the rate of change of cabin altitude in proportion to the rate of climb of the aircraft (between 300/500 ft per minute

Question 11

Isobaric controls schedule

Answer 11

When cruise altitude is reached the controller will switch to isobaric control to maintain a constant differential pressure if maximum differential pressure has been reached the controller will not allow any further increase in differential pressure and it will now be in Max. Diff. Control

Question 12

Proportional controls schedule Descending

Answer 12

Descent the controller will switch back to proportional control ROD 300 ft/minute to produce a Δ pressure of 0.1 psi on touchdown