Pneumatic System Flashcards
Pneumatic system provides
- AC distribution system
- AC cooling system
- Anti-g system
- Canopy seal system
- Canopy pressurization
- Cockpit temperature control
- Demist System
- Rain removal/ de-icing system
- Anti-ice system (engine only)
- Fuel System 4.5 bar press
- Hydr reservoir press
In the AC system cooling of the 2 heat exchangers is granted by:
Ram air while in flight
Ejector shut off valve, that opens automatically at speed below 165Kts
The mixing valve (mixing hot air w/ cold air by AC) is controlled by
Temperature Control Box
Emergency Cockpit ventilation system is composed of:
Ram air scoop
Over pressure dump valve
Below 8000ft you can pull the ram air scoop whenever needed, but what actions must be taken if above 8000ft?
Operate CABIN PRESS switch to OFF, interrupting canopy pressurization first, and wait if possible that outside pressure is similar to cockpit pressure
What does operation of ram air scoop handle also operate?
Over pressure dump valve
Power required for ventilation system comes from
Essential bus
Cockpit pressurization system components
Over pressure dump valve
Pressure regulator valve
Cockpit altimeter control system
When does overpressure dump valve close?
At 8000ft climbing
Normal operations of cockpit pressure regulation are solved by
Pressure regulator valve
Types of pressurization
h<8000 no pressurization
8000<h<16000 linear pressurization
h>16000 differential pressurization
When does the over pressure dump valve intervene?
When there’s a malfunction of the Pressure Regulator valve
If ram air scoop handle is pulled
If differential pressure is more than 27.6 +3.4/-0 kPa, or if cockpit is underpressure
CAB PRESS turns on if
Cockpit alt> 30.000ft or Cockpit px< 30 +1/-0 kPa
Differential pressure more than 27.6 +3.4/-0 kPa
Canopy seal inflates
Automatically after a takeoff because of a switch on the left landing gear leg.
At landing the operation is reversed
Air for the all pneumatic system is obtained by
8th stage of the compressor
Where does the anti-ice switch take power from?
Primary bus
How many parts in the anti-ice system?
Electric part: heaters are energized in the air intakes and air ducts
Pneumatic part: anti-ice valve opens taking air from the compressor and routing it to the engine front face
In case of electrical supply failure the engine anti-ice valve
Fails to the open position
When operating CABIN TEMP manually, the pilot must pay attention to what?
Not to set too cold temperatures to prevent ice formation in the water separator thus damaging the ducts
Effect of pressurization on cockpit altitude should be:
16.000<h<24.000 1/2h +-500ft
h>24.000 1/2h + 1000/2000ft
The Temperature Control Box is
Controlled by CABIN TEMP switch, based on 2 probes:
-cockpit temperature probe
-air inlet temperature probe
And it regulates the Mixing Valve for temperature in the cockpit
What is the differential pressure maintained by the Pressure Regulator Valve? In normal ops
3.5psi (24kPa)
