Air Conditioning¶
Air Conditioning: 01 General¶
The aircraft uses external air to supply: - The air conditioning and the ventilation systems - The pressurization system - The deicing system (Refer to ICE AND RAIN PROTECTION) Air inlets location: - Engines air intakes - Main landing gear fairings - Low pressure ground unit through a connector. The air intended for air conditioning and pressurization is pressurized by engines compressors and delivered through the bleed valves. It is conditioned by the packs, distributed to the pressurized zones then discharged overboard through two outflow valves. A part of this air is recirculated. Electric and electronic equipment and the forward cargo compartment are ventilated by cabin ambient air which is then recirculated or discharged outside the aircraft. The MFC provides the system monitoring and failures information to flight crew.
Air Conditioning: 02 Schematics¶
FUNCTIONAL ABSTRACTION - overall air-conditioning and ventilation schematic
RH ENG AIR INTAKE -> [RH PACK: valves / heat exchangers / ACM] ->+
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GROUND AIR -------> [GROUND CONNECTION] ----------------------> [MIXING CHAMBER]
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LH ENG AIR INTAKE -> [LH PACK: valves / heat exchangers / ACM] ->+
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+--------------------------------------+
v
[FLIGHT DECK + CABIN]
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| +--> [RECIRCULATION FAN] --+
| |
+--> [OUTFLOW VALVES] --> EXHAUST +--> return to mix
Each pack also has ram-air / ground-air cooling and an exhaust outlet.
Air Conditioning: 1 DESCRIPTION¶
Air Conditioning: 1.01 Air Production¶
The air conditioning system is equipped with two packs which regulate air flow and temperature as required. The packs cool, remove moisture and pressurize the bleed air. The two packs are installed in the main landing gear fairings and operate automatically and independently. The left pack supplies the cabin and cockpit with conditioned air, the right pack mainly supplies the cabin. INTERCONNECTION PACKS TURBO FAN RAM AIR INLET EXHAUST
If one pack is inoperative, the other one supplies both compartments through the mixing chamber. Hot bleed air from the engines is admitted through pack valves. The pack valve is pneumatically operated and electrically controlled. It is spring-loaded closed. When it is electrically energized the valve is ready to open provided sufficient air pressure. This butterfly valve has two functions: - Pack shutoff - Flow control: two levels are available normal or high flow. In high outside temperature conditions, selecting high flow increases the pack entrance pressure resulting in high flow pack output. Air is cooled: - By two ground turbo fans through turbo shutoff valves when: o IAS ≤ 150 kt and landing gear is retracted for less than 10 min Note In case of ENG OIL LOW PRESS, the turbo fan starts on the opposite side and is running as long as IAS ≤ 150 kt and regardless of landing gear position. o IAS ≤ 150 kt and landing gear is extended. - By ram air when IAS > 150 kt. Note Incorrect position of a turbo fan shutoff valve leads to closure of associated pack valve.
Air Conditioning: 1.02 Air Distribution¶
Conditioned air is blown into the cabin by outlet ramps under the overhead bins. It is then evacuated through guides along the cabin side walls at floor level. A part of it is recirculated by the fans, the other part being evacuated overboard through the outflow valves. The toilet is ventilated by differential pressure through a vent line. GENERAL AIR INLET PACK OUTFLOW VALVES AIR OUTLET CABIN AIR INLET GROUND COOLING FAN
CROSS SECTION
Air Conditioning: 1.03 Aircraft Ventilation¶
Flight deck, forward cargo compartment, electric and electronic equipment are ventilated by flow of ambient air which is: - Recirculated (underflow) to the pressurized compartment, or - Ducted overboard. The selection is operated by the overboard (OVBD) valve which controls the underfloor (U/F) valve: - OVBD full closed →U/F open - OVBD partially or full open →U/F closed - OVBD NORMAL MODE : Automatic selection - OVBD MANUAL MODE : to be used in case of AUTO MODE failure or, on ground, to accelerate cabin heating (Full closed position). Air is extracted by a fan which can operate at different speeds depending on flight deck temperature : Rotation speed is minimum below 20 °C (68 °F), maximum above 52 °C (126 °F) and varies linearly between these values. The fan is automatically cut off when there is smoke detection in the aft cargo compartment or in lavatory module. Only when OVBD VALVE AUTO MODE is selected, EXHAUST MODE pb may be used to control OVBD valve in a partially open position. This action is required in case of fan failure in order to create cabin differential pressure that generates some cooling air flow. In case of smoke in forward cargo compartment, flight deck air extraction duct can be closed with a lever on right side maintenance panel in order to avoid contaminated air suction to the flight deck.
U/F VENTILATION VALVE EXTRAC AIR FLOW VALVE OVBD VALVE TO OUT FLOW VALVES ZONE EXTRACT FAN UNDER FLOOR CABIN TEMP SENSOR SMOKE DETECTOR LAVATORY SMOKE DETECTOR AFT CARGO SMOKE DETECTOR CARGO FWD FLT CMPT ELECTRIC AND ELECTRONIC RACKS VENTILATION CLOSED OPEN EXTRACT AIR FLOW CAUTION; CLOSE ONLY IN CASE OF FWD COMPT SMOKE FAULT A AVIONICS VENT EXHAUST MODE N O R M CAUTION DO NOT SEL OVBO VALVE FULL OPEN IF P > 1PSI OVBD VALVE AUTO FULL OPEN FULL CLOSE FAULT OVBD
Air Conditioning: 1.05 Temperature Control¶
The system is designed to regulate and limit the temperature of the air discharged from the packs which is supplied to the different zones: - FLT COMPT by the left pack - CABIN by the right pack and excess air from the left pack. The pack temperature control valves adapt the amount of hot air mixed with the cool air in order to establish the required temperature. In automatic mode, each pack discharge temperature is controlled by an electronic temperature controller which computes the position of the temperature control valve taking into account: - Duct temperature - COMPT TEMP knob - Associated compartment temperature - Aircraft skin temperature. In manual mode, each pack temperature control valve is controlled directly by the COMPT TEMP knob and limited by the pneumatic temperature sensor.
Air Conditioning: 1.06 Overheat Protection¶
The pack valve closes automatically when the air downstream of the pack compressor overheats: T > 204 °C (399 °F). When duct temperature downstream of the mixing chamber increases over T = 88 °C (191 °F), the limiter closes the temperature control valve progressively by a pneumatic action in order to reduce hot air flow. An OVHT caution is provided to the flight crew when Tduct > 92 °C (198 °F) but the pack valve does not close.
Air Conditioning: 2 CONTROLS¶
Air Conditioning: 2.01 COMPT TEMP Panel¶
15 COMPT 100 50 0 30 25 20 DUCT COLD HOT OFF OFF FAULT FAULT COMPT TEMP RECIRC FAN 1 RECIRC FAN 2 A U T O A U T O TEMP SEL TEMP SEL OVHT MAN OVHT MAN HIGH FAULT OFF FAULT OFF AIR BLEED COLD HOT N O R M FLOW GRD X FEED PACK VALVE PACK VALVE C o COMPT SEL C O M P T C A B I N F L T FLT COMPT CABIN 1 2 3 4 5 6 7 8 9 1 3 4 5 8
1 PACK VALVE pb ON (pb pressed in) Associated PACK VALVE is open if electrical supply and air pressure are available Note A 6 s delay has been provided on right pack valve for passengers comfort purpose. OFF (pb released) Associated PACK VALVE is closed. The OFF light comes on white. “AIR PACK” caution is displayed on EWD when one of the pack valve is commanded OFF. “AIR PACK 1+2” caution is displayed on EWD when both pack valves are commanded OFF. FAULT Comes on amber and the caution message “AIR PACK” from the FWS is displayed on EWD associated with a Master Caution and a Single Chime when the PACK VALVE position disagrees with the selected position or in case of overheat downstream of the pack compressor (T > 204 °C/399 °F). In the later case, the valve is latched closed automatically. 2 FLOW pb NORM (pb released) Both pack valves are controlled automatically to give 22 psi regulated pressure. HIGH (pb pressed in) Both pack valves are controlled to give 30 psi regulated pressure which increases the flow accordingly. HIGH light comes on cyan. 3 COMPT TEMP knobs The temperature of the related compartment is controlled depending on the temperature control mode selected: - Automatic mode: The temperature of the compartment is controlled automatically according to the position of the knob - Manual mode: The knob controls directly the position of the temperature control valve. 4 TEMP SEL pb Selects the temperature control mode of operation. AUTO (pb pressed in) Automatic mode is selected. The electronic temperature controller controls the valve position. MAN (pb released) Manual mode is selected. The COMPT TEMP knob directly controls the position of the valve. The pneumatic temperature limiter limits the MAX duct temperature below T = 88 °C / 191 °F. The MAN light comes on cyan. OVHT Comes on amber and the caution message “AIR DUCT OVHT” from the FWS is displayed on EWD associated with a Master Caution and a Single Chime, when an overtemperature is detected in the duct (T > 92 °C / 198 °F). It is not inhibited in MAN mode.
5 RECIRC FAN pb Selects operation of the respective recirculation fan. ON (pb pressed in) Fan runs. Recirculation of a part of the cabin air to supplement the conditioned air supply is provided. Fan rotation speed linearly varies from 12700 RPM to 15600 RPM depending on temperature control valve position. If temperature measured at cabin floor level is lower than 13 °C (55 °F), high speed is automatically selected. OFF (pb released) Fan stops. All the air is supplied by the packs without recirculation. The OFF light comes on white. “AIR RECIRC FAN 1(2)” caution is displayed on EWD. FAULT Comes on amber and the caution message “AIR RECIRC FAN 1(2)” from the FWS is displayed on EWD associated with a Master Caution and a Single Chime, in case of: - The rotation speed of the fan becomes too low (<11400 RPM), or - The fan electrical motor overheats. 6 COMPT indicator Air temperature in the selected compartment is indicated in °C. 7 DUCT indicator For the selected compartment, the temperature of the conditioned air before leaving the duct is indicated in °C. Duct temperature is automatically limited to MAX 88 °C / 191 °F in AUTO mode or MAN mode. 8 COMPT SEL switch Selects the zone - FLT COMPT or CABIN - for which temperature (COMPT and DUCT) reading is desired. 9 GRD X FEED Refer to Crossfeed
Air Conditioning: 2.02 AVIONICS VENT Panel¶
FAULT AVIONICS VENT EXHAUST MODE N O R M CAUTION DO NOT SEL FULL OPEN IF P 1PSI OVBD VALVE AUTO FULL OPEN FULL CLOSE FAULT OVBD OVBD VALVE 1 2 3 1 OVBD VALVE Selector Switch AUTO Automatic operation of the overboard valve. The safety guard in auto position prevents valve opening control when cabin/exterior dP is greater than 1 psi FULL OPEN (cyan full open indicator on SD Cabin page): Serves to fully open the overboard valve when cabin/exterior dP is equal or lower than 1 psi FULL CLOSED (cyan full close indicator on SD Cabin page): Overboard valve closing control
2 EXHAUST MODE pb with Two Steady Positions PUSHED (NORMAL CONFIGURATION) involves electrical power supply of extraction fan. On ground, engine 1 not running (OIL LOW PRESS): - OVBD valve full open (green full open indicator on SD Cabin page) - U/F valve closed In flight, or on the ground, engine 1 running: - OVBD valve full closed (green full closed indicator on SD Cabin page) - U/F valve open RELEASED (“OVBD” legend ON) involves extraction fan power supply shut off. In flight (normal configuration): - Opening of the overboard ventilation valve in a intermediate position (green intermediate position on SD Cabin page) - Closing of U/F valve - Activation of following alarms: o Master caution o Single chime o FW caution message “AIR VENT EXH” on EWD o Exhaust OVBD status on SD Cabin page On ground: - Closing of U/F valve - Activation of mechanic call system if power supply through ground power unit is used - Activation of following alarms: o Master caution & Single chime (if condition levers are in a position other than FTR or FUEL S.O.) o FW caution message “AIR VENT EXH” on EWD o Exhaust OVBD status on SD Cabin page Note 1) Aircraft on ground and external power available: if EXHAUST MODE pb is set to OVBD position, the extract fan is OFF. A ground mechanic call is then generated to alert the flight crew that the avionics are not ventilated. 2) When start sequence is initiated, extract fan stops for 120 s to avoid pressure shocks. Exhaust mode fault comes on, however the ground mechanic call is not generated. “FAULT" indication on EXHAUST MODE pb “FAULT" legend comes on when AVIONICS/VENT/EXHAUST MODE pb is pushed and when following failures appear: - Rotation speed of air extraction fan is null or insufficient (fan failure or power supply loss)
- Excessive internal temperature (fan failure or simultaneous closing of overboard vent valve and underfloor vent valve) At the same time, the following alarms appear:
- Master caution & single chime (if conditions levers are in a position other than FTR or FUEL S.O.)
- EXHAUST VENT status and amber extraction fan indicator on the SD Cabin page. “FAULT" legend is off when EXHAUST MODE pb is released ("OVBD" legend on). When a SMK TEST is performed, FAULT light comes on to indicate that the extract fan is stopped. To restart it, it is necessary to manually reset the AVIONICS VENT EXHAUST MODE pb. 3 OVBD VALVE FAULT Caution Light
- Comes on amber when position of overboard valve does not correspond to control position
- Related warnings appear simultaneously: o Master caution o Single chime o FW caution message “AIR OVBD" on EWD o OVBD amber status on SD Cabin page.
Air Conditioning: 2.03 Flight Deck Ventilation Isolation¶
CLOSED OPEN EXTRACT AIR FLOW CLOSE ONLY IN CASE OF FWD COMPT SMOKE CAUTION:
CAUTION Close only in case of FWD COMPT smoke. Enables, in case of smoke in the forward cargo compartment, to isolate the flight deck ventilation, preventing smoke to enter the flight compartment.
Air Conditioning: 2.04 Display on SD Cabin Page¶
(1) PACK VALVE This indicators displays the status of the pack valve. Moreover, when high flow is selected on the Comp Temp Panel, a message shows AIR HIGH FLOW in cyan. (2) RECIRCULATION FAN – CABIN AIR DISTRIBUTION The SD Cabin provides information (highlights the faulty elements) on Recirculation Fan Status, as well as Cabin Air Distribution Duct indication. (3) CABIN AIR DISTRIBUTION DUCT Depending on the pack valve status and the recirculation fan status, the SD Cabin page provides visual information on cabin air supply. (4)–(5) VENTILATION : EXTRACTION FAN – OVERBOARD VALVE The SD Cabin page provides information on overboard valve and air extraction fan. (6)–(7) TEMPERATURE MANAGEMENT – CABIN TEMPERATURE The SD Cabin page provides information about on the cabin temperature and about the temperature management. The right hand indicator provides information from the cabin and the left hand indicator provides information from flight compartment.
14, 0, 4, 3 V13.2 L_CB_00000000_0000000_000_00_00
MFD
EXHAUST VENT EMER GPU 21 °C PACK BLEED AUTO HIGH FLOW AIR RECIRC PACK BLEED AUTO OXY SUPPLY PAX CREW P PSI 0 6 0 8 1.40 VS FT/MIN 0 2000 500 UP 2000 MAN ALT TARGET CAB ALT FT FT 5200 5200 OVHT LEAK CARGO REFUELING OVHT LEAK CABIN OVHD VALVE SVCE LO PR FWD COMPT XT FANS TEMP TEMP 4 3 8 1 7 2 5 6
ITEM DISPLAY DESCRIPTION EXTRACTION FAN ON EXHAUST OVBD EXHAUST MODE P/B RELEASED EXTRACTION FAN FAULT DISPLAY EXHAUST VENT 4 AUTOMATIC MODE OVBD VLV FULL OPEN AUTOMATIC MODE OVBD VLV IN (INTER. POSITION) AUTOMATIC MODE OVBD VLV FULL CLOSED OVBD VLV FAULT DISPLAY OVBD VLV OPEN OVBD VALVE OVBD VLV FAULT DISPLAY OVBD VLV CLOSED OVBD VALVE MANUAL MODE OVBD VLV FULL OPEN FULL OPEN MANUAL MODE OVBD VLV FULL CLOSED FULL CLOSE 5 AUTOMATIC TEMPERATURE CONTROL HOT DUCT OVERHEAT ALERT MANUAL TEMPERATURE CONTROL MAN AUTO 6 7 VALID SENSOR MEASUREMENT INVALID MEASUREMENT - - °C 21°C HIGH FLOW SELECTED AIR HIGH FLOW 8 ITEM DISPLAY DESCRIPTION 1 PACK VALVE ON PACK FAULT PACK VALVE OFF RECIRCULATION FAN ON Appears when BLEED pb and PACK pb are ON and: - The associated BLEED SOV is open and the associated engine is running (no OIL LOW PRESS + NH>60%) or, - The CVB is open (on ground when the PACK is feed by the opposite BLEED). Appears when PACK pb is OFF. Appears when MFC detects a fault in the associated PACK when the PACK pb is ON. PACK Stand-by All other conditions* PACK PACK invalid ** 2 3 RECIRCULATION FAN OFF RECIRC RECIRCULATION FAN 1 OR 2 OFF RECIRC RECIRCULATION FAN 1 OR 2 FAULT RECIRCULATION FAN FAULT PACK VALVES AND RECIRC FANS FAULT OFF ON BOTH SIDES BOTH PACK VALVES ON OR BOTH RECIRC FANS ON RIGHT PACK VALVE AND RECIRC FAN 1 OFF OR IN FAULT LEFT PACK VALVE AND RECIRC FAN 2 OFF OR FAULT
PACK PACK PACK PACK STBY OFF *The PACK Stand-by (PACK STBY) appears following the CAC internal logic. The most common configurations where the pack valve comes to STANDBY are: 1. Aircraft in flight: - PACK pb ON - BLEED pb OFF - No BLEED FAULT, no PACK FAULT 2. Aircraft on-ground: - PACK pb ON - BLEED pb ON - No BLEED FAULT (no leak, no overheat, no overpressure) - Engine OFF - CLA not in FUEL S.O. position
**The PACK Invalid appears as soon as the information used by the NAS is received as INVALID. The most common configurations where the pack valve comes to INVALID are: 1) Loss of communication between the NAS and the MFC (no input data available for NAS logic) 2) MFC declares the information as INVALID due to an internal problem.
Air Conditioning: 3 ELECTRICAL SUPPLY¶
Air Conditioning: 3.01 Electrical Supply¶
EQUIPMENT DC BUS SUPPLY (C/B) AC BUS SUPPLY (C/B) LH SIDE Pack valve DC ESS BUS (on lateral panel SYS1/PACK VALVE) NIL Recirculation fan DC UTLY BUS 1 (on lateral panel PWR SUPPLY CTL) NIL Pack and recirculation fan alert DC ESS BUS (on lateral panel SYS1/PACK and RECIRC FAN CAUTION) NIL FLT COMPT automatic temperature control DC ESS BUS (on lateral panel FLT COMPT/TEMP CTL/AUTO) NIL FLT COMPT manual temperature control DC ESS BUS (on lateral panel FLT COMPT/TEMP CTL/MAN) NIL RH SIDE Pack valve DC ESS BUS (on lateral panel SYS2/PACK VALVE) NIL Recirculation fan DC UTLY BUS 2 (on lateral panel PWR SUPPLY CTL) NIL Pack and recirculation fan alert DC ESS BUS (on lateral panel SYS2/PACK and RECIRC FAN CAUTION) NIL Automatic temperature control DC ESS BUS (on lateral panel CABIN/TEMP CTL/ AUTO) NIL Manual temperature control DC ESS BUS (on lateral panel CABIN/TEMP CTL/ MAN) NIL
EQUIPMENT DC BUS SUPPLY (C/B) AC BUS SUPPLY (C/B) Compartment and duct temperature indicator DC BUS 1 (on lateral panel COMPT and DUCT TEMP IND ) NIL TURBO FAN SHUT OFF VALVE 1 CTL DC BUS 1 (on lateral panel SYS1/TURBO FAN) NIL TURBO FAN SHUT OFF VALVE 2 CTL DC BUS 2 (on lateral panel SYS2/TURBO FAN) NIL OVBD valve, U/F valve DC EMER BUS (on lateral panel VALVES) NIL Extract fan control relay DC ESS BUS (on lateral panel CTL) NIL EXTRACT FAN Contactor DC BUS 2 (on lateral panel EXTRACT FAN) NIL EXTRACT FAN Contactor DC BUS 1 (on lateral panel EXTRACT FAN) NIL
Air Conditioning: 4 SYSTEM MONITORING¶
Air Conditioning: 4.01 AVIONICS VENT EXHAUST MODE FAULT-Alert¶
CONDITION VISUAL AURAL Underspeed or overheat of extract fan (T > 90 °C/ 194 °F) - MC light flashing amber - AIR VENT EXH amber message on EWD - EXHAUST FAULT amber message on Cabin SD page - EXHAUST MODE FAULT amber light on overhead panel SC
Air Conditioning: 4.02 OVBD VALVE FAULT-Alert¶
CONDITION VISUAL AURAL OVBD valve position not corresponding with aircraft condition - MC light flashing amber - AIR OVBD amber message on EWD - OVBD VALVE amber message on Cabin SD - FAULT amber light on overhead panel SC
Air Conditioning: 4.03 DUCT 1(2) OVHT-Alert¶
CONDITION VISUAL AURAL Overheat in the duct (T duct > 92 °C/ 200 °F) - MC light flashing amber - AIR DUCT 1(2) OVHT amber message on EWD - TEMP OVHT amber message on Cabin SD - Associated TEMP SEL OVHT amber light on overhead panel SC
Air Conditioning: 4.04 RECIRC FAN 1(2) FAULT-Alert¶
CONDITION VISUAL AURAL Recirculation fan underspeed or fan electrical motor overheat - MC light flashing amber - AIR RECIR FAN 1(2) amber message on EWD - Associated RECIRC FAN FAULT amber light on overhead panel - Associated RECIRC amber message on Cabin SD page SC
Air Conditioning: 4.05 PACK 1(2) VALVE FAULT-Alert¶
CONDITION VISUAL AURAL Pack valve position disagrees with commanded or overheat downstream of the compressor (T > 204 °C / 393 °F) - MC light flashing amber - AIR PACK amber message on EWD - PACK FAULT amber message on Cabin SD - Associated PACK VALVE FAULT amber light on overhead panel SC
Air Conditioning: 4.06 PACK 1+2 VALVES FAULT-Alert¶
CONDITION VISUAL AURAL Pack valve position disagrees with commanded or overheat downstream of the compressor (T > 204 °C / 393 °F) - MC light flashing amber - AIR PACK 1+2 amber message on EWD - Both PACK FAULT amber message on Cabin SD page - Both PACK VALVE FAULT amber lights on the overhead panel SC
Air Conditioning: 5 SCHEMATICS¶
Air Conditioning: 5.01 Air Conditioning¶
RH PACK PACK VALVE TEMP CONTROL VALVE GROUND UNIT CONNECTION ELECTRONIC TEMPERATURE CONTROL TEMPERATURE SENSORS CABIN FLT COMPT RH ENGINE BLEED AIR PACK VALVE TEMP CONTROL VALVE TEMPERATURE SENSORS ELECTRONIC TEMPERATURE CONTROL LH PACK GRD X BLEED MIXING CHAMBER RECIRCULATION FAN RECIRCULATION FAN OUTFLOW VALVE OUTFLOW VALVE LH ENGINE BLEED AIR
RH ENGINE BLEED --> [PACK VALVE] --> [RH PACK] --+
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GROUND UNIT ------------------------------------> [MIXING CHAMBER]
| ^
LH ENGINE BLEED --> [PACK VALVE] --> [LH PACK] --+ |
|
[FLIGHT COMPARTMENT] <--------------------+
[CABIN] <---------------------------------+
| |
[OUTFLOW VALVE] [RECIRCULATION FAN]
Temperature sensors -> electronic temperature control ->
associated temperature-control valve / pack-valve commands.
Air Conditioning: 5.02 Pack Schematics¶
0 COMPT 100 50 0 30 20 10 DUCT COLD HOT HIGH N O R M FLOW A U T O TEMP SEL OVHT MAN OFF PACK VALVE FAULT OFF ELECTRONIC TEMPERATURE CONT. BLEED AIR MAN. PACK VALVE DISAGREE T > 204° C RAM AIR INLET HEAT EXCHANGERS COMPRESSOR HOT BY-PASS VALVE TURBO FAN SHUT OFF VALVE GROUND INLET GROUND COOLING FAN TURBINE WATER EXTRACTOR TIC VALVE TEMP. CONTROL VALVE MIXING CHAMBER CONDENSER RECIRC. FAN AUTO COMPT. TEMP T > 88° C T > 92° C FAULT EXHAUST
FUNCTIONAL ABSTRACTION - one pack
BLEED AIR -> [PACK VALVE] -> [PRIMARY HEAT EXCHANGER] -> [COMPRESSOR]
|
v
[SECONDARY HEAT EXCHANGER]
|
v
[TURBINE] -> [WATER EXTRACTOR]
| |
+-------> [MIXING CHAMBER] --> PACK OUTLET
RAM AIR INLET --> heat exchangers --> EXHAUST
HOT BYPASS / TEMP CONTROL VALVE ---------------------> mixing chamber
Electronic temperature control receives selector/duct-temperature inputs
and commands pack, temperature-control, bypass and fan/shutoff functions.
Air Conditioning: 1 DESCRIPTION¶
Air Conditioning: 1.01 General¶
The cabin pressure is controlled by an electropneumatic valve and a pneumatic valve. These valves are on the lower fuselage skin in the rear underfloor zone and are operated by either of two control subsystems: - A digital electropneumatic sub-system : AUTO-mode - A pneumatic sub-system : MAN-mode An overpressure relief valve and a negative pressure relief valve are fitted on both outflow valves as safety devices. The controls related to the Cabin Pressure Control System (CPCS) are on the right side of the flight deck central instrument panel. Indicating is provided through SD cabin page, on the upper part of MFD. When the system is operating in the AUTO-mode, the pneumatic outflow valve is slaved to the electropneumatic valve. Their opening will be the same. In case of controller failure: - The positive differential pressure is limited to 6.35 psi by a manometric capsule. - The negative differential pressure is limited to -0.5 psi by a non return valve. Note The MAN RATE knob must be selected to NORM position in order not to disturb the automatic regulation.
Air Conditioning: 1.02 AUTO Mode¶
The digital controller is on the cabin pressure control system (CPCS) panel. It consists of an electronic box with a front panel and three plug-in modules as follows: - One module contains the electrical supply circuit, the power output circuit and subsidiary circuits - One module holds all the input circuits (including the pressure sensor) and the output circuits - The remaining module contains the central processor unit. With the AUTO-mode operating, the outflow valves are driven by the controller according to the information received with respect to: - Aircraft altitude obtained from Air Data Computer (ADC) via the CAC - Landing elevation, pre-selected by the ELV SET trigger switch - Takeoff elevation, memorised by the controller - Pressure cabin altitude, obtained from a pressure transducer inside the digital controller.
DIGITAL CONTROLLER DC BUS1 FLT GND 5 VDC LDG GEAR PROXSW P CABIN LANDING ELEVATION TAKE OFF ELEVATION AIRCRAFT DOOR CLOSED CAC1 ADC1 CAC2 ADC2 ELECTROPNEUMATIC OUTFLOW VALVE PNEUMATIC OUTFLOW VALVE NON PRESSURIZED AREA PRESSURIZED AREA
Air Conditioning: 1.03 Dump Function¶
A DUMP function is available to send a fully open electrical signal to the electropneumatic outflow valve. DUMP function is available as long as pressurization system is in AUTO mode. CAUTION The DUMP pb is guarded. No other safety device protects DUMP function from inadvertent use.
DIGITAL CONTROLLER DUMP ON ELECTROPNEUMATIC OUTFLOW VALVE PNEUMATIC OUTFLOW VALVE NON PRESSURIZED AREA PRESSURIZED AREA PNEUMATICALLY SLAVED
Air Conditioning: 1.04 Manual Mode¶
The electropneumatic outflow valve is maintained closed and the pneumatic outflow valve controls the cabin outlet air flow. Its control servo pressure is function of the manual controller demand. The control knob is used to select any cabin rate of change from -1 500 ft/min to +2 500 ft/min
CABIN PRESS FAULT MAN ELECTROPNEUMATIC OUTFLOW VALVE PNEUMATIC OUTFLOW VALVE NON PRESSURIZED AREA PRESSURIZED AREA I N C R E A S E D E C R E A S E N O R M MAN CAB ALT
Air Conditioning: 1.05 Ditching Mode¶
Two electrical motors (one for each outflow valves) maintain both outflow valves in closed position. Ditching mode is available in both automatic and manual mode.
DITCH ON ELECTROPNEUMATIC OUTFLOW VALVE PNEUMATIC OUTFLOW VALVE NON PRESSURIZED AREA PRESSURIZED AREA
Air Conditioning: 1.06 Ambient Pressure Sensor¶
It is composed of three modules that enable acquisition, process and transmission of cabin pressure data to the CAC. Both signals (pressure and pressure variation) are designed to provide an output between 0.5 V and 4.5 V, which enable failure detections out of this range. Signals from APS are sent to the CAC and processed to display as three indicators on the SD Cabin page : - Cabin altitude (ft): Determine the equivalent altitude associated the cabin pressure - VS (ft/min): Determine the equivalent altitude change associated to the pressure variation - ΔP (psi): Determine the pressure difference between the outside (provided by other pressure sensor) and the inside of aircraft.
Air Conditioning: 2 CONTROLS¶
Air Conditioning: 2.02 CABIN PRESS Indications¶
(Applies: 1054-1096;1237-1283) 1) CABIN PRESS IND The SD Cabin page gives the following information : - Cabin altitude, obtained from Ambient Pressure Sensor (APS) via the CAC - Rate of change of cabin altitude - Differential pressure between cabin pressure and outside static pressure. After conversion, data received from APS are sent by the CAC to both MFD to be displayed. 2) SD CABIN PAGE 1 Differential pressure indicator In the event of an excessive differential pressure, the CAC sends a warning signal to both MFCs and the alerting display is activated. 2 Cabin rate indicator Cabin rate of climb or descent are indicated on SD Cabin page. Invalid rate are also indicated and can be due to sensors failure or missing connectivity. An invalid speed can be due to sensors failure (out of range measurement) or a missing connection. 3 Cabin altitude indicator Cabin and target altitude are displayed. An invalid display can be due to sensors failure (out of range measurement) or a missing connection.
MFD
21 °C PACK HIGH FLOW AIR RECIRC PACK AUTO OXY SUPPLY PAX CREW P PSI 0 6 0 8 8.00 VS FT/MIN 0 2000 0 2000 MAN ALT TARGET CAB ALT FT FT 5200 5200 AUTO 1 3 2 FULL OPEN EXHAUST OVBD
ITEM DISPLAY DESCRIPTION 1 2 3 ITEM DISPLAY DESCRIPTION MAN ALT TARGET CAB ALT FT FT 5200 5200 AUTO PRESS CAB ALT FT 5200 CAB ALT FT 5200 MAN ALT TARGET CAB ALT FT FT 5200 5200 MAN ALT TARGET CAB ALT FT FT
5200 MAN ALT TARGET CAB ALT FT FT 5200
MAN ALT TARGET CAB ALT FT FT 8900 5200 AUTOMATIC PRESSURE CONTROL NOMINAL DISPLAY MANUAL PRESSURE CONTROL NOMINAL DISPLAY MANUAL PRESSURE CONTROL INVALID TARGET INVALID CAB ALT CAB ALT ALERTING DISPLAY CAB ALT PREVENTING DISPLAY AUTOMATIC PRESSURE CONTROL FAULT AUTO PRESS 0 6 8 3.00 - 0.25 0 6 8 7.00 0 6 8 _ . _ _ 0 6 8 P NOMINAL DISPLAY P PRE-ALERTING DISPLAY P ALERTING DISPLAY INVALID P _ . _ _ 0 2000 2000 RATE OF CLIMB INVALID RATE 500 UP 0 2000 2000 RATE OF DESCENT 1000 DN 0 2000 2000
(Applies: 1124-1160) 1) CABIN PRESS IND The SD Cabin page gives the following information : - Cabin altitude, obtained from Ambient Pressure Sensor (APS) via the CAC - Rate of change of cabin altitude - Differential pressure between cabin pressure and outside static pressure. After conversion, data received from APS are sent by the CAC to both MFD to be displayed. 2) SD CABIN PAGE 1 Differential pressure indicator In the event of an excessive differential pressure, the CAC sends a warning signal to both MFCs and the alerting display is activated.
2 Cabin rate indicator Cabin rate of climb or descent are indicated on SD Cabin page. Invalid rate are also indicated and can be due to sensors failure or missing connectivity. An invalid speed can be due to sensors failure (out of range measurement) or a missing connection. 3 Cabin altitude indicator Cabin and target altitude are displayed. An invalid display can be due to sensors failure (out of range measurement) or a missing connection.
MFD
21 °C PACK HIGH FLOW AIR RECIRC PACK AUTO OXY SUPPLY PAX CREW P PSI 0 6 0 8 8.00 VS FT/MIN 0 2000 0 2000 MAN ALT TARGET CAB ALT FT FT 5200 5200 AUTO 1 3 2 FULL OPEN EXHAUST OVBD
ITEM DISPLAY DESCRIPTION 1 2 3 ITEM DISPLAY DESCRIPTION MAN ALT TARGET CAB ALT FT FT 5200 5200 AUTO PRESS CAB ALT FT 5200 CAB ALT FT 5200 MAN ALT TARGET CAB ALT FT FT 5200 5200 MAN ALT TARGET CAB ALT FT FT
5200 MAN ALT TARGET CAB ALT FT FT 5200
MAN ALT TARGET CAB ALT FT FT 8900 5200 AUTOMATIC PRESSURE CONTROL NOMINAL DISPLAY MANUAL PRESSURE CONTROL NOMINAL DISPLAY MANUAL PRESSURE CONTROL INVALID TARGET INVALID CAB ALT CAB ALT ALERTING DISPLAY CAB ALT PREVENTING DISPLAY AUTOMATIC PRESSURE CONTROL FAULT AUTO PRESS 0 6 8 3.00 - 0.25 0 6 8 7.00 0 6 8 _ . _ _ 0 6 8 P NOMINAL DISPLAY P PRE-ALERTING DISPLAY P ALERTING DISPLAY INVALID P _ . _ _ 0 2000 2000 RATE OF CLIMB INVALID RATE 500 UP 0 2000 2000 RATE OF DESCENT 1000 DN 0 2000 2000
3) EWD High Altitude Airport Operation HI ALT mode activates automatically before takeoff and landing from airports with an altitude above 8 500 ft. In HI ALT mode, cabin altitude monitoring thresholds are raised to take into account the airport elevation. When HI ALT mode is active, green HI ALTmemo appears on the EWD. EWD HI ALT
Air Conditioning: 2.03 AUTO PRESS Panel¶
LANDING ELEVATION FAST N O ft DUMP TEST DESCENT RATE ELV SET AUTO PRESS N O R M + - 1 2 3 4 5 1 LANDING ELEVATION indicator Displays in ft the landing elevation setting. The two last digits always display 0. All digits turn off in case of automatic system failure, manual mode or DUMP mode. 2 ELV SET trigger switch Enables selection of the elevation of the planned destination airport in 100 ft increments. The landing altitude ranges between -1 500 ft and 10 000 ft. 3 DESCENT RATE pb Is operated to enable a fast cabin descent. NORM (pb released) The max cabin vertical speed in descent is -400 ft/min. FAST (pb pressed in) The max cabin vertical speed in descent is -500 ft/min. The FAST LIGHT comes on cyan. 4 TEST pb When pressed, the system is electrically tested. If the system is ready to use, the LANDING ELEVATION indicator displays alternately 18800 and -8800. FAULT light comes on amber on CAB PRESS MODE SEL pb. In flight, this test is inhibited.
5 DUMP guarded pb DUMP guarded pb enables selection of the dump function when in AUTO mode. NORMAL (pb released) The digital controller operates normally. ON (pb pressed in) The digital controller is out of circuit and an electrical opening signal is sent to the electropneumatic outflow valve. Both outflow valves fully open. The ON light comes on white. Note When the DUMP guarded pb is pressed while in AUTO mode, the FAULT light of the MAN PRESS CONTROL panel comes on amber.
Air Conditioning: 2.04 MAN PRESS Panel¶
MODE SEL CAB PRESS DITCH 1 3 O N MAN FAULT 2 MAN CAB ALT
1 MODE SEL pb Selects the pressure control mode: AUTO (pb pressed in) The digital controller is in operation. MAN (pb released) The digital controller is out of operation, digits turn off and the manual controller regulates the pressure. The MAN light comes on white. “AIR AUTO PRESS” caution is displayed on EWD. FAULT The light comes on amber to indicate a digital controller failure, “AIR AUTO PRESS” caution is displayed on EWD. Note The FAULT light comes on amber when in AUTO mode, the DUMP guarded pb is pressed in. 2 MAN RATE knob In manual mode, the control knob is used to select any cabin rate of change from -1 500 ft/min to +2 500 ft/min. NORM This position must be used when in AUTO mode. 3 DITCH guarded pb Selects the ditch mode. ON (pb pressed in) Both outflow valves are forced to closed position regardless of the pressure control mode. The ON light comes on white.
Air Conditioning: 3 ELECTRICAL SUPPLY¶
Air Conditioning: 3.01 Electrical Supply¶
EQUIPMENT DC BUS SUPPLY (C/B) AC BUS SUPPLY (C/B) Digital controller DC BUS 1 (on lateral panel AUTO PRESS) NIL Ambient Pressure Sensor DC EMER BUS (on lateral panel APS) NIL DITCH DC EMER BUS (on lateral panel DITCH) NIL
Air Conditioning: 4 SYSTEM MONITORING¶
Air Conditioning: 4.1 AUTO PRESS FAULT-Alert¶
CONDITION VISUAL AURAL Digital controller failure - MC light flashing amber - AIR AUTO PRESS amber message on EWD - FAULT amber light on CAB PRESS MOD SEL pb - AUTO PRESS amber message on Cabin SD SC
Air Conditioning: 4.2 EXCESS CAB DELTA P-Alert¶
CONDITION VISUAL AURAL Differential pressure > 6.6 psi - MW light flashing red - EXCESS CAB Δ P red message on EWD - The ΔP value is displayed white on red background on Cabin SD page - DIFF PRESS local indicator exceeds 6.6 psi on the cabin SD page CRC
Air Conditioning: 4.3 EXCESS CAB ALT-Alert¶
(Applies: 1054-1096;1237-1283) CONDITION VISUAL AURAL Cabin altitude > 10 000 ft (inhibited on ground and during 2 min after takeoff) - MW light flashing red - EXCESS CAB ALT red message on EWD - Red reverse video ALT flashing on Air Cabin SD page CRC
(Applies: 1124-1160) CONDITION VISUAL AURAL Cabin altitude > 10 000 ft (15 000 ft in High Altitude mode) - MW light flashing red - EXCESS CAB ALT red message on EWD - Red reverse video ALT flashing on Air Cabin SD page CRC
Air Conditioning: 4.4 CABIN ALTITUDE-Alert¶
(Applies: 1054-1096;1237-1283) CONDITION VISUAL AURAL 9 500 ft < Cabin altitude < 10 000 ft - MC light flashing amber - CAB ALT amber message on EWD SC
(Applies: 1124-1160) CONDITION VISUAL AURAL 9 500 ft < Cabin altitude < 10 000 ft - OR - 14 000 ft < Cabin altitude < 15 000 ft (in High Altitude mode) - MC light flashing amber - CAB ALT amber message on EWD SC
Air Conditioning: 4.5 CABIN DELTA P-Alert¶
CONDITION VISUAL AURAL 6.25 psi < Cabin ΔP < 6.6 psi - OR - -0.5 psi < Cabin ΔP < -0.2 psi - MC light flashing amber - CAB ΔP amber message on EWD SC
Air Conditioning: 4.6 NEGATIVE CABIN DELTA P-Alert¶
CONDITION VISUAL AURAL CAB ΔP < –0.5 psi - MW light flashing red - NEGATIVE CAB Δ P red message on EWD CRC
Air Conditioning: 4.7 Ditch Mode-Alert¶
CONDITION VISUAL AURAL Both outflow valves selected in DITCH position. - MC light flashing amber - AIR DITCH amber message on EWD - ON white light on DITCH pb SC
Air Conditioning: 5 SCHEMATICS¶
Air Conditioning: 5.01 Schematics¶
FUNCTIONAL ABSTRACTION - automatic/manual pressurization
PRESSURIZED AREA --------------------+---------------- NON-PRESSURIZED AREA
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+----------------------+----------------------+
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[ELECTROPNEUMATIC OUTFLOW VALVE] [PNEUMATIC OUTFLOW VALVE]
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[ELECTRIC MOTOR] [VACUUM RELAY]
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+---- AUTO PRESS / CAC reference signal ------+
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manual control CAB PRESS indication
Outside static pressure supplies the reference-pressure side.
Both valve paths include negative-pressure relief; overpressure relief is
provided between pressurized and non-pressurized areas.