The Airbus Safety Magazine Residual Cabin Pressure 3 Cabin

The Airbus Safety Magazine Residual Cabin Pressure 3 Cabin-Free PDF

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3 Cabin pressure 3 2 Cabin pressure system, review The following generic principles apply to all. AIRBUS A C ,3 1 RPWS Residual Pressure Warning, System a Control and regulation. of the cabin altitude , In case of cabin residual pressure differential a The cabin altitude is managed and controlled by. warning light flashes red at each door as long as a semi or fully automatic system which ensures. Dp 2 5 hPa provided that one engine two on seamless and rate limited changes of the cabin. A340 is stopped and the slide is not armed at this altitude as the A C climbs or descends with an. door absolute limitation at 8000 ft maximum cabin, altitude This system performs the management. This Residual Pressure Warning System red light and control of the internal cabin in fact cabin . is basic on A320 Family A330 A340 cockpit cargo air pressure by tuning at each. moment the position of outflow valves, OFV which let air escape from the cabin .
In case of failure of the automatic systems , the crew must ensure the cabin pressure. management manually thanks to direct, control of the outflow valves at slow closing. or opening speeds by means of an UP , DN control switch UP for cabin altitude. up open OFV DN for cabin altitude down, close OFV . Should the cabin altitude exceed limits , positive about 8 8 PSI above external.
ambient pressure negative about 1 PSI, below external ambient pressure safety. valves will open to protect A C structure, and passengers crew . RPWS does not cover all the scenarii it remains,inhibited if . The slides are still armed emergency evacuation , Engines are running . In addition the RPWS is only a passive protection . it also relies on cabin crew compliance to procedures . Safety first 03 December 2006 2 10, CRUISE, Actual A C altitude.
Automatic complet, opening of the OFV, Cabin altitude sec after touchdow. Slight over , Pre pressurization pressurization De pressurization. on the ground at TO before landing after landing, b Typical cabin pressurization c Cockpit sliding windows . schedule on the ground and in flight Each AIRBUS A C has cockpit sliding windows . This chart identifies the characteristic phases of which may be opened to cope with some. the automatic A C cabin pressurization schedule emergency situations for instance smoke removal . in particular those which may participate to a They may be used to depressurize the A C but. residual cabin pressure build up on the ground their opening is possible only if Delta P is below a. certain value typically 0 2 PSI at 180 kt due to, Pre pressurization on the ground at TO to avoid the force exerted on them because of the Delta P . slight pressure bump at A C rotation due to the, high angle of attack and air cushion effect on d Cabin fuselage drain valves .
the aft OFV which would cause reverse airflow A number approximately 15 of piston type drain. entering the cabin through the OFV valves are fitted along the bottom line of the. Slight over pressurization before landing for the fuselage to drain condensation water or other fluid. same reason as above leaks They close when P between the cabin. De pressurization after A C touchdown pressure and the outside ambient air pressure. Automatic control of the complete opening of exceeds a certain value between 1 and 2 PSI . the outflow valves x seconds after A C i e 70 to 140 hPa But their effective section is. touchdown small about 50 mm2 each , Safety first 03 December 2006 3 10. 3 3 Operational cases where a residual because of A C damage a slight P may be. cabin pressure may develop kept if the CPCS was in auto mode 10 hPa. or less Obviously if the erroneous landing field, RTO followed by an emergency evacuation elevation selector was not in auto and an. the A C is still pressurized for instance 15 hPa erroneous selection was set a larger P may. on WB and 7 hPa on SA LR The level of exist and a significant amount of time may be. residual P at A C stop will depend on several necessary for A C depressurization . Whether or not the CPCS is still electrically Notes same as above for RTOs . supplied and functioning with necessary inputs, like landing gear signals which may be lost After use of the MAN mode . to send the OFVs opening control signals i e emergency descent or CPCS failure bad or. Wwhether or not the system integrity is sufficient incomplete application of the ECAM or QRH. possible OFV damage loss of elec power procedure during landing A C return to gate on. and if yes whether or not enough time is left A C not yet having the automatic outflow valve. for the control x sec after touch down of an opening on the ground in MAN mode . effective full OFV opening in the same conditions as above on A C equipped. with automatic outflow valve opening on the ground. Notes in MAN mode failure of this function , If the crew is not disabled as said earlier they can open. the cockpit sliding windows for A C depressurization but Non deliberate selection of the DITCHING. this is possible only if P is 0 2 PSI function , In an emergency evacuation situation the door slides will Untimely DITCHING control signal .
be kept armed so the local warnings at each door RPWS DITCHING mode used e g for AEVC reset on. signalling a residual cabin pressure 2 5 hPa will not be the A320 then not de selected after use . given A cabin P will build up if valves are fully or. partially closed doors are closed and airflow, enters the cabin . At landing in case of runway overrun or, lateral excursion followed by an emergency A C operation under MEL condition . evacuation the aft valve must be closed and more time is. the ground depressurization sequence may not needed for the A C depressurization on the. be complete or even not performed in case of ground particularly if the operational procedure. landing gear damage with flight ground signals is not followed sel one pack OFF immediately. lost or if the outflow valves remain closed after A C touch down . Safety first 03 December 2006 4 10, 4 Review of the FCOM During flight crew training concerning an emergency. evacuation the accent is put particularly on the, procedures in aborted takeoff following an engine fire or an APU. fire The check of the delta P is highlighted The, manual mode delta P should be at zero before the evacuation.
order is given to the cabin crew,In case of dual system failures an ECAM warning. is triggered and a procedure requests to control Cabin crew training . manually the cabin pressure The training for cabin crew highlights that before. In addition the system page will show that the opening any passenger door the cabin crew has. system 1 2 are inoperative to check the cabin pressure indicator . This manual control is done through the MAN V S He she must inform the cockpit crew if the red. CTL light flashes , Before any opening of the door he she must. Depending on the failure mode it is possible that hold the door assist handle . this procedure may not allow the depressurization . In any case it is clearly requested through a caution If on ground in auto mode few minutes after. to check that delta P is zero before opening doors landing 3 minutes on A330 A340 the outflow. valve is not fully open CAB PRESS OUTFLOW, If for any reason there is still significant cabin VALVE NOT OPEN ECAM warning is displayed . pressurization it is possible to refer to the cabin It requests to open it in manual mode or to switch. overpressure procedure Only on the A320 family off the packs if unsuccessful . due to single outflow valve configuration paper,procedure . Safety first 03 December 2006 5 10, 5 Safety enhancement Before Mod .
CPCS ATA21, modification CPC 2, description, Cockpit CPC 1 AFT. 2 modifications have been launched both for A320 Panel Auto OFV. family and A330 A340 to cope with cases of,inappropriate compliance of the procedures in Man. manual mode after landing Mode,5 1 Automatic outflow valve opening. After Mod , in manual mode, CPCS ATA21, This ground logic unit is an electronic box containing CPC 2 FWD. Auto OFV,hardwired programmed logic, It will be supplied from the DC ESS bus and will force Cockpit CPC 1 AFT.
the automatic opening of the outflow valves on the Panel Auto OFV. ground in cabin pressure manual mode or in failure. cases It drives 2 relays one per outflow valve to Man. provide electrical power directly to their manual mode Mode. electrical motor taking over their control , So this new function will mitigate against the hazard. of flight crew using the MAN pressure mode in RPCU. flight and then not following the FCOM procedure Electric ENGINES. after landing i e fully open the OFVs It will take ATA24 ATA73. over the control of the OFV automatically by means. of providing electrical power directly to their manual Landing. Navigation Doors,motors using external relays ATA34. It will also mitigate against the hazard of,maintenance personnel being interrupted in the. accomplishment of a pressurization test on the,ground or CPCS failure power supply cut off . This new device is installed on The logic for the RPCU is as follows . A320 family aircraft through modification Briefly each outflow valve will fully open if . 34673 SB 21 1154 and Landing gear shock absorbers compressed or. parking brake applied , on A330 A340 through modification 53145 Thrust levers is in TO position .
SB 21 3113 for A330 No engine is running above idle and no ADIRS. SB 21 4122 for A340 basic delivers Vc 70 kt , SB 21 5021 for A3456 The valve is in MAN control and both CPCs are. Wiring in stby , SB 21 3112 for A330 The valve angle is 100 . SB 21 4121 for A340, SB 21 5020 for A3456, Safety first 03 December 2006 6 10. 5 2 New red ECAM warning in case of In case of excessive cabin residual pressure after. residual cabin pressure independent engines OFF on ground for more than 7 seconds . of the pressurization system CAB PR EXCES RESIDUAL PR red warning will. be activated after a time delay of 5 seconds , In addition to this hardware device a new red The P sensor used for this new warning is. ECAM warning has been created in case of that of the RPWS . impossibility to release the cabin pressure blanket The tables here below show the ECAM. manual motor jam misapplication of the manual procedures without and with this new red. procedure ECAM procedure , CAB PR EXCES RESIDUAL PR.
The first table shows the existing procedure in case of residual cabin pressure . Safety first 03 December 2006 7 10, The second table shows the ECAM procedure with the FWC logic in case. of residual cabin pressure ,This new red ECAM warning is available for. A330 A340 with FWC through modification, A320 family with FWC H2F3 A318 PW Mod 52306 SB 31 4083 for A340 200 300. certification through modification Mod 51973 SB 31 5015 for A340 500 600. Modification 35220 SB 31 1267 Mod 51790 SB 31 3066 for A330. Safety first 03 December 2006 8 10, 6 Conclusion Even if it is always possible for a customer to ask. for the non embodiment of these safety enhan , In service experience shows that several events cements on a brand new aircraft in particular the.
of residual cabin pressure have been reported and installation of the RPCU it is Airbus position that. led to violent door opening with potential for serious both modifications will bring an additional safety. injuries net , Most of the cases have been reported on A300 Consequently Airbus highly recommends the. and were related to ground tests or ground air cart installation of the RPCU and of the relevant FWC . supplying the aircraft where ground mechanics as described here below . opened a cabin door while the aircraft was still, pressurized Automatic opening of the outflow valve even. in manual mode when on ground , The latest events resulted from misapplication of It will be supplied from the DC ESS bus and will. the Manual mode procedure after landing force the automatic opening of the outflow valves. on the ground in cabin pressure manual mode or, In case of dual pressure system failures an ECAM in failure cases. warning is triggered and a procedure requests to This new device is installed on. control manually the cabin pressure A320 family aircraft through modification 34673. In addition the system page will show that the SB 21 1154 and. system 1 2 are inoperative A330 A340 through modification 53145 . This manual control is done through the MAN V S SB 21 3113 for A330 SB 21 4122 for A340. CTL basic SB 21 5021 for A3456, In any case several procedures are in place in New red ECAM warning in case of residual.
order to allow the release of the residual cabin cabin pressure. pressure if any In addition it is clearly requested In case of excessive cabin residual pressure on. through a caution to check that delta P is zero ground 7 seconds after engines OFF CAB PR. before opening doors EXCES RESIDUAL PR red warning will be activated . In case of cabin pressure double failure the The P sensor used for this new warning is that. procedures must be followed up to the end manual of the RPWS . opening of the outflow valve and control of the, cabin pressure on ground This new red ECAM warning is available for. A320 family with FWC H2F3 A318 PW,To cope with non compliance with the above certif. the A320 then not de selected after use A cabin P will build up if valves are fully or partially closed doors are closed and airflow enters the cabin A C operation under MEL condition the aft valve must be closed and more time is needed for the A C depressurization on the ground particularly if the operational procedure is not followed sel one pack OFF immediately after A C

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