2 Air Systems Flashcards
ISOLATION VALVE SWITCH
- auto
AUTO
- Closes isolation valve when BOTH engine bleed air switches are on AND BOTH packs are out or HIGH
- Opens isolation valve when EITHER engine bleed air switch switch OR air conditioning pack switch is OFF.
🟧 WIND BODY OVERHEAT
L and R
Left: overheat from: bleed air duct leak in Engine strut, left inboard LE wing, Left A/C bay, APU bleed air duct, keel beam
Right: overheat from: bleed air duct leak in right engine strut, right inboard LE wing, right a/c bay
ENG/APU bleed air switch
operates when
ON: valve will open WHEN ENG/APU is operating
🟧 BLEED TRIP OFF
illuminate when
Excessive bleed air pressure OR temperature. Automatically immediately closes ENG bleed air valve. It requires reset
TRIP RESET SWITCH
Resets:
Opens:
🟧 PACK, 🟧 BLEED TRIP OFF, 🟧 ZONE TEMP LIGHT.
Related Engine bleed air valve opens, OR related pack valve opens OR related air mix valve opens
🟧 ZONE TEMP
Illuminate:
Illuminate during Mast Caut:
CONT CAB indicates duct temperature overheat OR failure of BOTH the flight deck primary and standby temperature control.
During Mast Cat either:
- CONT CAB failure of primary OR standby flight deck temperature control. Or
- FWD or AFT cabin indicates failure of associated zone temperature control.
[lights will extinguish when master caution reset.
Temp selecter OFF
Closes trim air modulating valve
- Also closes when 1 Duct overheat. The valve may be reopened after duct has cooled by pushing TRIP RESET
A/C PACK SWITCH
- AUTO
- HIGH
AUTO
- both packs operating: in LOW flow
- one pack operating: in HIGH flow with FLAPS UP
- when operating pack with APU bleed air: regulates to HIGH flow (with both ENG BLEED AIR vales closed)
HIGH
- packs regulating to HIGH flow
- provides max flow rate on ground with APU bleed air ON
AIR TEMP SOURCE SELECTOR
- supply duct
- PASS CAB
- PACK
S - selects appropriate zone supply duct temperature
P - selects forward or aft passenger cabin temperature
Pack - selects left OR right pack temperatures
TRIM AIR SWITCH
Trim air pressure regulating and shutoff valve signaled open (when ON) or closed (when OFF)
RECIRCULATION FAN SWITCHIES - AUTO
- In flight
- On ground
Flight
- Left recirculation Fan operates if BOTH packs are operating UNLESS ONE in HIGH
- Right recirculation Fan operates if BOTH packs are operating UNLESS BOTH in HIGH
Ground
- Left recirculation Fan operates if BOTH packs are operating UNLESS BOTH in HIGH
- Right recirculation Fan operates if BOTH packs are operating EVEN in HIGH
🟧 PACK
- Trip off OR failure of BOTH primary and secondary pack controls
- During Recall: Failure of primary OR secondary pack control
Cabin Altitude Indicator
- Indicate at or below 0’
Inner/Outer scale
Cabin altitude off less than 0 feet and reach upper end scale of cabin altitude indicator when:
- On Ground at airports close to OR below Sea Level
- in Flight when cabin is pressurized below sea level.
Inner = Cabin altitude
Outer = Differential pressure
Altitude horn cutout switch
- Push:
- cuts out intermittent cabin altitude warning horn
- altitude warning horn sounds when cabin altitude is MORE THAN 10.000 feet
Landing Altitude Selector
Flight Altitude Selector
- Both feet and increments
- Panel failure of either Selector
L - [-1.000 - +14.000 feet] in 50’ increments
F - [-1.000 - +42.000 feet] in 50’ increments
- A panel failure detected after a DC power interruption will result in 88.888 OR all dashes.
Outflow Valve Position indicator
Outflow valve Switch
- operates in all modes
- only operates in MAN mode
ENG BLEED AIR VALVE
DUCT PRESSURE TRANSMITTER
ISOLATION VALVE
APU BLEED AIR VALVE
- when apu shut down
9th stage ENG bleed air valve closing
E - DC activated and PRESSURE operated
D - Indicator is AC operated
I - AC operated
A - DC controlled and PRESSURE operated, when APU is shut down it automatically closes
9 - ENG at IDLE thrust AND ENG BLEED AND APU Bleed valves are open gives possibility of bleed back-pressuring the 9th stage. This would cause 9th stage bleed air valve to close.
🟧 DUAL BLEED
- when
- limit
ENG and or Isolation switch AND APU Bleed switch open/ON
- MUST limit thrust to IDLE otherwise possible pack pressure on APU
APU BLEED AIR: sufficient
SINGLE PACK HIGH FLOW:
Amount of packs per ENG
A - For 1 pack in FLIGHT or 2 packs on Ground
S - maintaining pressurization and normal temperature up through max specified altitude
A - MAXIMUM 1 Pack per Engine
One pack Fails, one Engine fails OR One pack is Selected to OFF [Both packs AUTO and ENG Bleed air Switch On]
- Aircraft NOT on ground AND the flaps are UP
- Aircraft on Ground OR the flaps are down
APU is operating and AOU bleed switch is ON, both ENG bleed switches are set to OFF and botch packs set to AUTO
- Remaining pack automatically switches to HIGH air flow to increase ventilation
- Remaining pack will remain with current flow
- Automatic switching to HIGH flow occurs with a single pack failure, regardless of flap position or air/ground status.
Zone temperature control
from 18 to 30 degrees
Packs produce temperaturs for:
Coldest selected temperature [with single pack AND TRIM AIR off: average selected temperature]
ZONE TEMPERATURE CONTROL
Left electronic controller
Right electronic controller
- Failure of Primary flight deck temperature control
- Both L and R fail
Failure of FWD or AFT cabin temp control
L - AFT cabin and backup flight deck
R - FWD Cabin and main flight deck
- Cause an automatic switch to backup control and will illuminate CONT CAB 🟧 ZONE TEMP light
- Master Caution
F - cause associated trim air modulating valve to close. Temperature selector will have AVERAGE temperature of FWD and AFT CAB
Any failure affecting supply of trim air will cause:
- L pack
- R pack
Passenger cabin zone trim air OR all trim air is lost:
The temperature control system to control both packs independently .
L - conditioned air to flight deck at selected temperature
R - Satisfy demand of cabin zone which requires most cooling
FWD and AFT zone temperature demands will be averaged for for control of right pack
All zone controls AND primary pack controls fail
All temperature selectors OFF
- STBY pack control controls average FWD and AFT temperature demands
- trim air modulating valves will close
left pack 24 degrees and Right pack 18 degrees (as measured at pack temperature sensors)
Flight deck
- air vents/ ducts
- L pack
- air diffuser under captain/ F/o seats delivers continues air flow (as long manifold is pressurized)
- overhead diffuser (aft and above window 3) can be turned ON/OFF
- Valve behind rudder ( to warm feet and defog NO 1 windshield
- Most air goes to mix manifold, rest to CONT CAB
Recirculation Fans
- driven by
- air flow
- Driven by AC motors
- air from passenger cabin AND electrical equipment bay is drawn to the FWD cargo bay (where it is filtered and recirculated) to MIX manifold
Equipment Cooling System
- purpose
🟧 OFF
- Overtemperature on ground
P - cools electronic equipment in the flight deck and E and E bay
🟧 - Loss of airflow due to failure of an equipment cooling fan, selecting the alternate fan should extinguish the light within 5 seconds
O - alerting provided through call horn in Nose Wheel
RECIRC FAN SWITCHES OFF AND PACK SWITCHES HIGH, this automatically will cause:
- but with any record fan OR pack switch moved out of position:
- smoke control relay will shut off equip cooling supply fan for 5minutes, after 5 min normal operations return
- smoke control relay will INHIBIT EQUIPMENT COOLING 🟧 OFF light for 5 minutes, after 5 minutes return to normal operation
- equipment cooling exhaust fan will be shut off for the remainder of the flight
B - electronic equipment cooling fans will begin to operate again.
when overboard exhaust vale closed:
exhaust air (equip cool) is also diffused into FWD cargo bay for additional heating
Pressurization
- valves
2 pressure relieve valves prevent cabin pressure differential exceeding 9.1 PSI
Outflow valve: [behind AFT cargo bay] passe
and overboard exhaust valve
CABIN PRESSURE CONTROLLER
- AUTO
- ALTN
- MAN
A - automatic uses DC motor
A - automatic uses DC motor
M - Manual uses DC motor
Outflow by 2 valves:
2nd: operation in smoke removal config
Outflow valve: [behind AFT cargo bay] passenger cabin air drawn through floor (foot level grills) towards aft cargo compartment. There heated and than discharged overboard through outflow valve
Overboard exhaust valve: [fwd of fwd cargo] on GND OR in FLT with low differential pressure:
- warm air from E and E bay discharged overboard,
In flight with high differential pressure:
- overboard exhaust valve normally closed and exhaust air is diffused to the lining of forward cargo compartment
NOTE: overboard exhaust valve is driven open if EITHER pack in HIGH and recirc fan OFF, this allows increase of ventilation
AUTO MODE OPERATION
- controllers (during GA)
- depressurization
- pressurize start
C - one controller alternately sequenced as primary controller for every new flight, other served as back up
During GA - controller automatically pressurizes during APP for comfortable GA (with minimum pressure changes)
D - cabin is depressurized on ground at low thrust setting, outflow valve will be fully open
- high thrust setting on Ground, slightly pressurizes cabin for comfortable t/o segment
🟧 OFF SCHED DESCENT
illuminate:
- descending before reaching selected FLT ALT
- controller automatically programs the cabin to land at T/O airport, BUT when FLT ALT is changed this auto program is automatically stopped
CRUISE MODE ACTIVATED
-when:
DESCENT MODE ACTIVATED
- when:
FLT ALT, diff pressure limit
W - aircraft climbs within .25psi of selected FLT
W - aircraft descend .25 psi below the selected FLT
at or BELOW 28.000 feet
- 7.45 PSI
28.000 - 37.000 Feet
- 7.80 PSI
ABOVE 37.000 Feet
- 8.35 PSI
🟧 AUTO FAIL (controller)
- illuminates when:
actions:
MAN MODE
I - Loss of DC power, controller fault, outflow valve control fault
- excessive differential pressure (>8,75 PSI) when controller not responding properly
- excessive rate of cabin change not responding properly
- high altitude (>15.800 feet) when controller not properly responding
A - Automatically transfers to the ALTN mode, 🟧 AUTO FAIL still on until manually selected to ALTN
M - separate DC motor powered by DC Standby System, outflow valve full range of motion (takes approximately 20 seconds)