Pneumatics Flashcards
When will the crossbleed open in the AUTO position?
When an engine is being started using a pneumatic source from the other side of the system. Example: cross beed start, Engine #2 start using APU bleed, Engine #1 start using external air source)
With the APU Bleed open and Engine Bleeds closed, what position must the crossbleed be in to power both PACKS?
The XBLEED knob must be set to OPEN to power both PACKS.
List the Engine Bleed, APU Bleed, crossbleed and PACK configuration for the following:
a. Engine Start Procedure
b. Taxi
c. Before Takeoff (reduced thrust)
d. Before Takeoff (icing)
e. Before Takeoff (full thrust, non-icing)
f. Cruise
Engine Start Procedure: Engine Bleeds: CLOSED APU Bleed: OPEN XBLEED: OPEN PACKS: OFF
Taxi: Engine Bleeds: OPEN APU Bleed: CLOSED XBLEED: AUTO PACKS: ON
Before Takeoff (reduced thrust) Engine Bleeds: OPEN APU Bleed: CLOSED XBLEED: AUTO PACKS: ON
Before Takeoff (icing) Engine Bleeds: OPEN APU Bleed: CLOSED XBLEED: AUTO PACKS: ON
Before Takeoff (non-icing) Engine Bleeds: CLOSED APU Bleed: OPEN XBLEED: OPEN PACKS: ON
Cruise: Engine Bleeds: OPEN APU Bleed: CLOSED XBLEED: AUTO PACKS: ON
How would the bleeds and packs be configured for a takeoff using ALT-T/O thrust if the crew elects to shut down the APU prior to takeoff?
Engine Bleeds: OPEN
APU Bleed: CLOSED
XBLEED: AUTO
PACKS: ON
How would the bleeds and PACKS be configured for an icing takeoff?
Engine Bleeds: OPEN
APU Bleed: CLOSED
XBLEED: AUTO
PACKS: ON
How would the bleeds and packs be configured for a takeoff using T/O or E/TO thrust in non-icing conditions if the crew wants to ensure the PACKS operate during takeoff?
Engine Bleeds: CLOSED
APU Bleed: OPEN
XBLEED: OPEN
PACKS: ON
Regarding the priority logic of the available bleed sources, if the APU bleed was selected OPEN, what would occur after opening the engine 1 bleed valve?
The APU bleed valve would close. Engine bleed has priority.
What are the indications of a bleed leak?
A red “LEAK” inscription appears over the button of the affected bleed. Additionally, the EICAS BLD 1(2) LEAK master warning will be presented.
What indications would be visible on the APU bleed valve button if the APU is OFF and the APU bleed valve is selected OPEN?
A white bar only. The “OPEN” inscription would not be visible.
While taxiing in icing conditions, is it possible for the APU bleed to be used on the ground for the PACKS while simultaneously using engine lip anti-ice protection?
Yes, the bleed air used for engine lip and anti-ice protection does not require the engine bleed valve to be open.
For non-icing takeoffs using T/O or E-T/O, is it mandatory that APU be used as a pneumatic source for the PACKS during takeoff?
No, the crew may elect to utilize an APU-off takeoff regardless of planned thrust/anti-icing configuration, for operational or fuel conservation purposes.
What is the procedure for a cross bleed engine start?
The aircraft must be stopped with the parking brake set. Prior to commencing the cross-bleed start, ensure that the bleed of the operating engine is selected OPEN, the bleed of the engine to be started is CLOSED, the APU bleed is closed and the cross-bleed knob is AUTO or OPEN.
Increase the N2 to 83% on the operating engine and position the START/STOP selector knob from STOP to START. Pause for 2 seconds in the RUN position prior to selecting START.
Describe the power sources of the pneumatics panel?
RECIRC - Shed Buses PACK 1 - DC GASPER - DC PACK 2 - DC XBLEED - Essential BLEED 1 - Essential APU BLEED - Essential BLEED 2 - Essential
What do the PACKS do?
PACK - Pneumatic Air Conditioning Kit also known as ECU - Environmental Control Unit
- Provide air conditioning to the cabin
- The air conditioning provided to the cabin is also used for pressurization
Where do we draw engine bleed air?
We draw air from the 9th and 14th stage.
