AIR_BLEED AIR CONTROL PANEL Flashcards
DUAL BLEED Light
What does this mean? (1sp)
[1sp: it means you have 2 pneumatic sources pressurizing the same manifold at the same time]
Illuminated (Amber):
- APU bleed air VALVE open and
- Eng 1 Bleed SWITCH on - OR -
- Eng 2 Bleed SWITCH ON and Isolation VALVE open
- indicates that 1 or both engines AND APU are supplying pneumatic duct pressure at the same time
- set power no higher than IDLE (just in case APU check valve fails)
- looks at ENG BLEED SWITCH positions and APU and ISOLATION VALVE positions
RAM DOOR FULL OPEN Light
Why is the ram door full open light always on when on the ground? (1sp)
When will the ram air door (blue light) goes out? (1sp)
When in cruise will they go to the open position? (1sp)
[1sp: because it works with the air ground sensor
(b) it works with the flaps - after takeoff when you start retracting the flaps it will start moving to the closed position. At flaps up they will drive to full close
(c) when we start extending the flaps. ]
Illuminated (BLUE):
- indicates ram door is fully open
- this happens when on the ground - OR -
- inflight with FLAPS EXTENDED
- normally closed in flight
-
if OPEN in flight (other than flaps extended) it could mean:
- ram air system blockage
- heat exhangers are dirty
- electrical failure
L/R RECIRC FAN Switches
OFF:
- fan is signaled off
- in flight if R recirc fan is turned OFF - the OEV will OPEN (verified by slight increase in cabin climb)
AUTO: - Logic sequence below -
-
GROUND:
-
PACKS AUTO (both)
- both recirc fans are on
-
PACKS HIGH (either one)
- both recirc fans are on
-
PACK HIGH (both)
- LEFT recirc fan shuts down (right is on no matter what on the ground)
-
PACKS AUTO (both)
-
INFLIGHT:
-
PACKS AUTO (both)
- both recirc fans are on
-
PACKS HIGH (either one)
- LEFT recirc fan shuts down
-
PACK HIGH (both)
- BOTH recirc fans shut down
-
PACKS AUTO (both)
Power sources:
- L recirc fan is powered from Main Bus 1
- R recirc fan is powered from Main bus 2
BLEED AIR DUCT PRESSURE Indicator
- Indicates pressure in L and R bleed air ducts
- AC operated
WING-BODY OVHT TEST Switch
Activate:
-
PUSH:
- tests wing-body overheat detector circuits
- illuminates BOTH Wing-Body Overheat lights (plus MC & AIR COND lights)
- if it FAILS then no lights illuminate
L / R PACK Switches
OFF: Pack is signaled OFF
AUTO: - logic -
- Both Packs operating = Low Flow (normal)
-
One Pack operating = High Flow (on that pack - inflight with FLAPS UP)
- this AUTO Switching feature only works inflights with the flaps up (not on ground or with flaps down)
- One Pack supplied by APU (both Eng Bleed switches must be OFF) = High Flow
HIGH:
- pack regulates to high flow
- provides max flow rate ON GROUND with APU BLEED AIR switch - ON
-
impacts Recirc fan logic:
- Ground: if both are in High - the left recirc fan stops
- Inflight: if either are in High - the left recirc fan stops (opens the OEV)
- Inflight: if both are in High - both recirc fans stop
ISOLATION VALVE Switch
How does the isolation valve work in the AUTO position? (1sp)
Is the isolation valve in auto - normally open or closed? (1sp)
[1sp: normally closed. when will it be OPEN in auto? If any of the 4 corner switches are placed to OFF position]
CLOSE: closes isolation valve - isolating both sides of the system
AUTO:
- automatically CLOSES isolation valve - ALL CORNER SWITCHES are ON or AUTO/HIGH (normal)
- automatically OPENS - if ANY CORNER SWITCH - PACK or Eng BLEED SWITCH is in OFF
OPEN:
- opens isolation valve connecting both sides
L / R ENG BLEED AIR Switches
OFF: closes engine bleed air valve (PRSOV)
ON:
- opens engine bleed air valve (PRSOV) when engines are operating
- PRSOV is spring-loaded closed with no pneumatic pressure
- electrically activated - pneumatically actuated
APU BLEED AIR Switch
OFF:
- closes the APU bleed air valve
- turning the APU start switch OFF also closes APU bleed valve - [DUAL BLEED] light goes out
ON:
- opens the APU bleed air valve when APU is running
- DC power and APU compressor air required to OPEN and STAY open
PACK Light
What can cause the PACK light to come on? (1sp)
[1sp: means the respective pack overheated or the temp is too high and the respective pack valve will close.]
Illuminated (amber):
- indicates a PACK trip OFF - OR -
- BOTH primary and standby pack controller failure
-
DUAL CHANNEL LIGHT:
- if light comes on immediately - overheat OR loss of both pack controllers
- if during recall: loss of one pack controller (switches to backup automatically) - MC, PACK and AIR COND lights all go out when MC recall is pressed
- if BOTH controllers fail FOR THE SAME PACK that pack will still operate but without any temperature control unless excessive temps cause the pack to trip off
- if BOTH pack lights are on - both valves may have closed which means you will get a gradual loss of cabin pressure and eventually a CABIN ALTITUDE warning
- can be RESET using TRIP RESET button
WING-BODY OVERHEAT Light
What do you think the QRH will direct you to do if this light comes on? (1sp)
[1sp: since you cant reset this light the qrh will direct you to reduce power (once you have a leak) by reducing power you reduce pressure, and by reducing pressure you reduce the leak.]
Illuminated (amber):
- Both lights indicate an bleed air leak in the following:
- Related Eng Strut
- Related Inboard Wing Leading Edge
- Related Air Conditioning Bay
- the LEFT light additionally indicates a bleed air leak in the following:
- Keel Beam
- APU bleed air duct
Note: the TRIP RESET button will NOT reset this light - also no Valves automatically move with this light its just for informational purposes to the crew
BLEED TRIP OFF Light
What can cause the bleed trip off light to come on? (1sp)
[1sp: excessive pneumatic temperature or pressure]
Illuminated (amber):
- excessive engine bleed air TEMP or PRESS
- related engine bleed air valve CLOSES AUTOMATICALLY
Notes.
- requires reset (from TRIP RESET button)
- the associated pack will also close since there will not be any air to open the pack valve
- electrically activated - pneumatically operated
- light stays on until TRIP RESET is pushed
- after light comes on expect to see 0 pressure on that side of the system
- if happens on takeoff (especially a bleeds off takeoff) its probably an over pressure situation
- Over Pressure - instant reset when power is reduced
- Over Temp - (delayed reset due to cool down time)
TRIP RESET Button
- press if fault is corrected
- resets the following lights and valves:
- BLEED TRIP OFF (and reopens the valve)
- PACK (and reopens valve)
- ZONE TEMP (and reopens related air mix valve)
- lights remain ON until reset
- does NOT reset the WING-BODY OVERHEAT light
