Pneumatic system Flashcards
Which failure is the bleed system cause ECAM warning?
- Overheat
- Overpressure
- Leakage
- Discontinuity: Valve position disagree with command
How does the bleed pressure regulation work?
The bleed valve, which is downstream of the junction of HP and IP ducting, acts as shut off and pressure regulating valve
How does bleed temperature regulation work?
A precooler downstream of the bleed valve regulates the temp of bleed air.
Precooler is an air to air heat exchanger that use cooling air from engine fan to regulate the temp ≈ 200⁰C.
Which systems or components are supllied by high pressure air?
- Air conditioning
- Water tank pressurization
- Hydraulic reservoir pressurization
- Wing anti ice
- Engine starter
- Fuel inerting system
- Cargo heating
Pneumatic system operation is controlled and monitered by….
Two Bleed Monitoring Computers
(BMC)
What are high pressure air source?
- Engine
- APU
- Ground unit (HP and LP)
How does a leak detection system work?
It detecs any overheating in the vincinity of hot air duct
One loop system for APU and pylon
Two loop system for wing.To activate a wing leak signal, two loop must detect the leak or one loop if the other one is inoperative
What is the function of crossbleed valve?
Allows the air supply systems of two engines to be isolated or interconnected
What occurs if one BMC fails?
Bleed Monitoring Computer
The other one take over most of the function
* Lost bleed valve auto close function (related side)
* Lost leak warning function (related side)
* Lost the associated FAULT light on AIR COND panel (CEO only)
On what ECAM page you will get information abt PNEUMATIC system?
BLEED page
How does APU bleed valve work?
APU bleed valve operate as a shut off valve to control APU bleed air. It is electrically controlled and pneumatically operated
What does the amber “FAULT” light in the APU BLEED pb indicate?
APU bleed leak
What does the amber “FAULT” light in the ENG BLEED pb indicate?
- Overpressure
- Overheat
- Wing or Pylon Leak
- Bleed valve not close during engine start or APU bleed ON
What occurs if BMC 1 fail?
Bleed Monitoring Computer
- Lost auto close function of engine bleed valve 1 and APU bleed valve
- Lost leak warning function of engine 1 and APU
- Lost “FAULT” light of engine bleed pb and APU bleed pb (CEO only).
When will bleed valve auto close?
- During engine start
- APU bleed ON
- ENG FIRE pb pushed
- Ditching pb pushed
- Overpressure
- Overheat
- Leak
When will APU bleed valve auto close
- APU leak
- Left wing leak
- Pylon 1 leak
(except when engine start)
What logic control the X-bleed when X-bleed in auto?
- X-bleed open when APU bleed valve open
- X-bleed close when APU bleed valve close or when wing, pylon, APU leak
(Except during engine start)
If APU is running, is it necessary to manually select APU BLEED OFF prior to APU shutdown?
NO
On ECAM BLEED page, how can you tell if GND HP air supply is connected?
Ground High Pressure air
The GND unit temp and press are indicated on the ECAM BLEED PRECOLLER 1
How GND LP air is supplied to aircraft?
Ground Low Pressure air
The air is supplied direct to mixture unit
If the engine bleed air in-flight is too low, what will occur?
Engine speed is auto increased to provide adequate bleed air pressure
After enigne start with APU bleed ON, what source is supplying bleed air to the packs?
APU bleed
Can external HP source be used for air conditioning?
Maybe
Which part of the engine did the pneumatic system take air from?
Normally from intermediate pressure stage (IP) of engine HP compressure.
At low speed when temp and press of IP are too low, air is drawn from HP stage.
Can IP and HP stage supply bleed air at the same time?
NO
Can BLEED valve of engine 2 open while APU bleed ON
Yes, when X-bleed is closed
How many motors are controlling the X-bleed valve?
Two electric motors, one for manual, one for automatic
When will PRECOOLER INLET PRESSURE indicated amber?
Below 4 psi or abv 57-60 psi
What is normal range of PRECOOLER OUTLET TEMP?
Abv 150⁰C and not exceeds
- 290⁰C for 5s
- 270⁰C for 15s
- 257⁰C for 55s
How do you know LP unit has been disconected from A/C ?
Check there is no air coming from the air cond vent
