Pneumatic Flashcards
What is the high pressure air is used for ?
For air conditioning, pressurization, hydraulic tank pressurization, wing anti ice, water tank pressurization and engine start.
From where the bleed air from the IP valve is bled from ?
From the 7th Intermediate Pressure (IP) stage from the engine High Pressure (HP) compressor section
What is the purpose of the IP check valve ?
To prevent bleed air from circulating back to the 7th stage compressor.
What happens if IP pressure is not sufficient ?
Engine bleed air is bled from the High Pressure valve
What is the minimum required amount of bleed pressure before the HP valve opens ?
At least 8 PSI to open the HP valve
From where the bleed air from the HP valve is bled from ?
From the 10th High Pressure (HP) stage
What is the normal bleed pressure that the system maintains ?
It maintains at 36 PSI +/- 4 PSI
What is the purpose of the bleed valve, aka pressure regulator vavle (PRV) ?
The valve acts as a shutoff valve and regulates pressure to 45 PSI +/- 5 PSI
What is the possible fluctuation regarding the bleed air pressure during climb up to FL100 ?
It may fluctuate between 38 PSI and 56 PSI at high engine power during climb up to FL100
What is the purpose of the overpressure valve ?
The valve protects the system from overpressure. It is fully automatic and can not be controlled by pilots.
What is the maximum pressure to reach before the overpressure valve closes to reduce pressure ?
80 PSI (75 PSI on NEO)
What is the purpose of the precooler ?
As the temperature of the bleed air is regulated by the precooler, it acts as a heat exchanger that uses cold fan air to maintain the temperature at 200°C
How is the bleed air cooled down ?
By a fan air valve that draws air from the engine fan to the precooler. It closes if temp °C is below 200°C, or opens if temp °C is above 200°C
What is the purpose of the crossbleed valve ?
It allows the air supply systems of the two engines to be interconnected or isolated
How many motors does the crossbleed valve have ?
2 electric motors, one for AUTO mode and one for MANUAL mode
How many loops do the wings have ?
Both wings have a dual loop (loop A and loop B)
What happens when a leak is detected ?
If a leak is detected by both loops (or one loop with the other one inoperative), a wing leak signal is sent
How many loops do the pylons and the APU have ?
a single loop
How is the wing protected from overpressure ?
The wing is equipped with a blown down panel to protect the integrity of the leading edge bay against overpressure
How many underwing blown down panels are there ?
5 underwing blown down panels :
- 3 inboard of the engine pylon
- 2 outboard of the engine pylon
What is the minimum pressure required in the leading edge before an overpressure is triggered ?
When the pressure reached approx 7 PSI, the rivets of the panel shear and the trailing edge opens, venting the air overboard
What happens during a BMC failure ?
The other BMC takes over control, but the associated FAULT light is not operative anymore and the associated bleed valve does not close automatically.
What is the required upstream pressure to open the bleed air valve ?
above 8 PSI
When does the precooler inlet pressure become amber on the ECAM page ?
If under 4 PSI, or if an overpressure is detected (threshold between 57 and 60 PSI)
When does the precooler outlet temperature °C become amber on the ECAM page ?
If an over temperature (or low temperature) is detected :
- 290°C for more than 5 seconds, or
- 270°C for more than 15 seconds, or
- 257°C for more than 55 seconds
When a low temperature situation can be detected ?
Only in-flight, if bleed temp °C is below 150 °C, with wing anti-ice ON and bleed air valve (PRV) open
When does the ARROW (wing anti ice) on the ECAM page become amber ?
- Valve is open and air pressure is low or high, or
- Valve is open on the ground for more than 10 seconds
