DOC AIRBUS | AMM A320FAIR DISTRIBUTION AND RECIRCULATION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. Cabin Air Distribution and Recirculation
The cabin air distribution system supplies conditioned air to the cabin and to the cockpit. The Cockpit and cabin main supply ducts come from the mixer unit, which is the central element of the distribution system.
The air flows out of the cabin through the lower sidewall-panels (dado panels) to the underfloor area.
A part of the exhaust air of the cabin and the underfloor area is mixed with fresh air from the air conditioning packs in the mixer unit. This recirculated air is drawn by recirculation fans through recirculation filters to the mixer unit.
The cabin air distribution system supplies conditioned air to the cabin and to the cockpit. The Cockpit and cabin main supply ducts come from the mixer unit, which is the central element of the distribution system.
The air flows out of the cabin through the lower sidewall-panels (dado panels) to the underfloor area.
A part of the exhaust air of the cabin and the underfloor area is mixed with fresh air from the air conditioning packs in the mixer unit. This recirculated air is drawn by recirculation fans through recirculation filters to the mixer unit.
B. Cockpit Air Ventilation
The cockpit-air ventilation system supplies temperature controlled and conditioned air to the cockpit. The airflow comes from the cabin air distribution system from the mixer unit in a separate duct. The air flows from air outlets and individual air outlets into the cockpit.
The cockpit-air ventilation system supplies temperature controlled and conditioned air to the cockpit. The airflow comes from the cabin air distribution system from the mixer unit in a separate duct. The air flows from air outlets and individual air outlets into the cockpit.
2. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 15HG | RECIRC FAN 1 | 131PW | 137 | 21-21-51 | |
| 14HG | RECIRC FAN 2 | 132PW | 138 | 21-21-51 | |
| ** ON A/C NOT FOR ALL | |||||
| 4010HM | RECIRC FILTER HOUSING 1 | 131PW | 137 | 21-21-45 | |
| 4011HM | RECIRC FILTER HOUSING 2 | 132PW | 138 | 21-21-45 | |
| ** ON A/C NOT FOR ALL | |||||
| 4012HM | RECIRC FILTER CARTRIDGE 1 | 131PW | 137 | 21-21-41 | |
| 4013HM | RECIRC FILTER CARTRIDGE 2 | 132PW | 138 | 21-21-41 | |
| ** ON A/C ALL | |||||
| 4020HM | RECIRC CHECK VALVE 1 | 131PW | 137 | 21-21-42 | |
| 4021HM | RECIRC CHECK VALVE 2 | 132PW | 138 | 21-21-42 | |
| ** ON A/C NOT FOR ALL | |||||
| 4010HM | RECIRC FILTER HOUSING 1 | 137 | 21-21-45 | ||
| 4011HM | RECIRC FILTER HOUSING 2 | 138 | 21-21-45 | ||
| ** ON A/C NOT FOR ALL | |||||
| 4012HM | RECIRC FILTER CARTRIDGE 1 | 137 | 21-21-41 | ||
| 4013HM | RECIRC FILTER CARTRIDGE 2 | 138 | 21-21-41 | ||
3. System Description
A. Air Supply and Ducting for Passenger Cabin
Air Distribution - Passenger Cabin ** ON A/C NOT FOR ALL
Air Distribution - Passenger Cabin ** ON A/C NOT FOR ALL
The passenger cabin is divided into the FWD and AFT distribution zones which are supplied with temperature controlled and conditioned air.
The conditioned air provided by the air conditioning packs 10HM (11HM) is supplied through a mixing unit installed under the cabin floor (in front of frame 36). Cabin air which has entered the underfloor area, is drawn through recirculation filters 4012HM (4013HM) by recirculation fans 14HG (15HG). The recirculation fans blow the air through check valves 4020HM (4021HM) to the mixing unit. The mixing unit mixes the conditioned air from the conditioning packs with the cabin recirculation air.
The quantity of cabin recirculation air mixed with conditioned air changes between 34% - 36% (in normal operational cases).
This is related to the position of the flow selector 5HB
The quantity of cabin recirculation air mixed with conditioned air changes between 40% - 48% (in normal operational cases).
This is related to the position of the flow selector 5HB
The quantity of cabin recirculation air mixed with conditioned air changes between 29% - 42% (in normal operational cases).
This is related to the position of the flow selector 5HB
From the mixing unit, the air is supplied to the cabin zones through ducts with different diameters. Large diameter supply ducts are installed under the cabin floor along the left-hand and right-hand side.
Smaller diameter riser ducts with integrated sound absorbers are connected to the main supply ducts. The riser ducts supply the air to the cabin zones through cabin air outlets installed below and above the hatracks.
Additional riser ducts are installed at the rear of the FWD passenger doors, and also forward of the AFT passenger doors.
The cabin and door outlets are positioned to prevent draughts at seat-head level, and divide the air equally through the cabin zones.
Most of the distribution ducts are made of resin and glassfiber laminate with metal sleeves bonded to each end for duct interconnection. Flexible bellows, which are made of silicone laminate and glassfiber, connect the ducts to each other. Clamps secure the flexible bellows. Insulation shells which are made of polyethylene foam or glass wool (covered with a Hypolon material) are installed around the ducts.
Air Distribution - Passenger Cabin ** ON A/C NOT FOR ALL Air Distribution - Passenger Cabin ** ON A/C NOT FOR ALL The conditioned air provided by the air conditioning packs 10HM (11HM) is supplied through a mixing unit installed under the cabin floor (in front of frame 36). Cabin air which has entered the underfloor area, is drawn through recirculation filters 4012HM (4013HM) by recirculation fans 14HG (15HG). The recirculation fans blow the air through check valves 4020HM (4021HM) to the mixing unit. The mixing unit mixes the conditioned air from the conditioning packs with the cabin recirculation air.
The quantity of cabin recirculation air mixed with conditioned air changes between 34% - 36% (in normal operational cases).
This is related to the position of the flow selector 5HB
The quantity of cabin recirculation air mixed with conditioned air changes between 40% - 48% (in normal operational cases).
This is related to the position of the flow selector 5HB
The quantity of cabin recirculation air mixed with conditioned air changes between 29% - 42% (in normal operational cases).
This is related to the position of the flow selector 5HB
From the mixing unit, the air is supplied to the cabin zones through ducts with different diameters. Large diameter supply ducts are installed under the cabin floor along the left-hand and right-hand side.
Smaller diameter riser ducts with integrated sound absorbers are connected to the main supply ducts. The riser ducts supply the air to the cabin zones through cabin air outlets installed below and above the hatracks.
Additional riser ducts are installed at the rear of the FWD passenger doors, and also forward of the AFT passenger doors.
The cabin and door outlets are positioned to prevent draughts at seat-head level, and divide the air equally through the cabin zones.
Most of the distribution ducts are made of resin and glassfiber laminate with metal sleeves bonded to each end for duct interconnection. Flexible bellows, which are made of silicone laminate and glassfiber, connect the ducts to each other. Clamps secure the flexible bellows. Insulation shells which are made of polyethylene foam or glass wool (covered with a Hypolon material) are installed around the ducts.
B. Emergency Ram Air Inlet
If there is a failure in both air conditioning packs, the emergency ram air inlet supplies the fresh air for the mixer unit. The air from the emergency ram air inlet is sufficient to supply the cockpit and cabin zones.
If there is a failure in both air conditioning packs, the emergency ram air inlet supplies the fresh air for the mixer unit. The air from the emergency ram air inlet is sufficient to supply the cockpit and cabin zones.
C. LP Ground Connector
When the aircraft is on ground, the air distribution and recirculation system can be supplied with air from the low pressure ground connector. A ground air cart can supply air into the system when the engines or the APU do not operate.
You must not use conditioned air from the packs and the LP ground Unit at the same time.
When the aircraft is on ground, the air distribution and recirculation system can be supplied with air from the low pressure ground connector. A ground air cart can supply air into the system when the engines or the APU do not operate.
You must not use conditioned air from the packs and the LP ground Unit at the same time.
D. Cockpit Distribution
Air from the mixing unit is supplied to the cockpit through a duct installed below the left-hand side of the cabin floor. Conditioned air is supplied to the cockpit at the these places:
Air from the mixing unit is supplied to the cockpit through a duct installed below the left-hand side of the cabin floor. Conditioned air is supplied to the cockpit at the these places:
- the left-hand side of the Captain's station,
- the left-hand side of the Captain's feet area;
- the right-hand side of the First Officers station,
- the right-hand side of the First Officers feet area,
- at two positions in the left-hand ceiling area above the third crew member's station.
- the left-hand and right-hand ceiling areas above the lateral windows,
- the left-hand and right-hand sides below the lateral windows.
- at the left-hand and right-hand ceiling areas above the windshield.
E. Mixing Unit
The mixing unit is installed under the cabin floor in front of frame 36. It mixes conditioned fresh air and recirculated cabin air before distribution to the system. The unit is made of two parts, the mixing chamber and the distribution head. The mixing chamber is made of resin and glassfiber laminate with a metal flange bonded to the top. Connected to this flange is an aluminum distribution head which distributes mixed-air to the system supply ducts and which contains the hot air supplies for both cabin zones.
Crossfeed ducts are installed between the distribution head and the main supply ducts. These are made of aluminum and contain noise-attenuators. The main supply duct to the cockpit is made of aluminum at its interface with the hot trim-air system.
An electrically operated back-up flap is installed in this duct. This flap makes sure that sufficient fresh air is delivered to the cockpit in case of a pack 1 failure (Ref. AMM D/O 21-51-00-00). The electrically operated back-up flap also operates in the case of the 24 DEG.C (75.20 DEG.F) back-up mode (when the cockpit is supplied by pack 1 only). Noise-attenuators are installed downstream of the hot trim-air interface. The mixing unit and crossfeed ducts are insulated with glasswool and a jacket made of a Hypolon material.
The mixing unit is installed under the cabin floor in front of frame 36. It mixes conditioned fresh air and recirculated cabin air before distribution to the system. The unit is made of two parts, the mixing chamber and the distribution head. The mixing chamber is made of resin and glassfiber laminate with a metal flange bonded to the top. Connected to this flange is an aluminum distribution head which distributes mixed-air to the system supply ducts and which contains the hot air supplies for both cabin zones.
Crossfeed ducts are installed between the distribution head and the main supply ducts. These are made of aluminum and contain noise-attenuators. The main supply duct to the cockpit is made of aluminum at its interface with the hot trim-air system.
An electrically operated back-up flap is installed in this duct. This flap makes sure that sufficient fresh air is delivered to the cockpit in case of a pack 1 failure (Ref. AMM D/O 21-51-00-00). Noise-attenuators are installed downstream of the hot trim-air interface. The mixing unit and crossfeed ducts are insulated with glasswool and a jacket made of a Hypolon material.
The mixing unit is installed under the cabin floor in front of frame 36. It mixes conditioned fresh air and recirculated cabin air before distribution to the system. The unit is made of two parts, the mixing chamber and the distribution head. The mixing chamber is made of resin and glassfiber laminate with a metal flange bonded to the top. Connected to this flange is an aluminum distribution head which distributes mixed-air to the system supply ducts and which contains the hot air supplies for both cabin zones.
Crossfeed ducts are installed between the distribution head and the main supply ducts. These are made of aluminum and contain noise-attenuators. The main supply duct to the cockpit is made of aluminum at its interface with the hot trim-air system.
An electrically operated back-up flap is installed in this duct. This flap makes sure that sufficient fresh air is delivered to the cockpit in case of a pack 1 failure (Ref. AMM D/O 21-51-00-00). The electrically operated back-up flap also operates in the case of the 24 DEG.C (75.20 DEG.F) back-up mode (when the cockpit is supplied by pack 1 only). Noise-attenuators are installed downstream of the hot trim-air interface. The mixing unit and crossfeed ducts are insulated with glasswool and a jacket made of a Hypolon material.
The mixing unit is installed under the cabin floor in front of frame 36. It mixes conditioned fresh air and recirculated cabin air before distribution to the system. The unit is made of two parts, the mixing chamber and the distribution head. The mixing chamber is made of resin and glassfiber laminate with a metal flange bonded to the top. Connected to this flange is an aluminum distribution head which distributes mixed-air to the system supply ducts and which contains the hot air supplies for both cabin zones.
Crossfeed ducts are installed between the distribution head and the main supply ducts. These are made of aluminum and contain noise-attenuators. The main supply duct to the cockpit is made of aluminum at its interface with the hot trim-air system.
An electrically operated back-up flap is installed in this duct. This flap makes sure that sufficient fresh air is delivered to the cockpit in case of a pack 1 failure (Ref. AMM D/O 21-51-00-00). Noise-attenuators are installed downstream of the hot trim-air interface. The mixing unit and crossfeed ducts are insulated with glasswool and a jacket made of a Hypolon material.
F. Air Recirculation
Cabin air from the underfloor area is mixed with conditioned air. This increases the amount of air which is blown into the distribution system. The two recirculation fans 14HG (15HG) installed one each side of the mixing unit do this. Cabin air is drawn through two recirculation filters 4012HM (4013HM) with their appropriate housings 4010HM (4011HM) and blown through two check valves 4020HM (4021HM) into the mixing unit.
Cabin air from the underfloor area is mixed with conditioned air. This increases the amount of air which is blown into the distribution system. The two recirculation fans 14HG (15HG) installed one each side of the mixing unit do this. Cabin air is drawn through two recirculation filters 4012HM (4013HM) with their appropriate housings 4010HM (4011HM) and blown through two check valves 4020HM (4021HM) into the mixing unit.
** ON A/C NOT FOR ALL
5. Component Description
A. Cabin Recirculation Fans FIN: 14-HG FIN: 15-HG
The cabin recirculation fans 14HG (15HG) are installed in line with the recirculation ducts. They are powered by a three-phase six-pole induction motor that drives a fan-wheel which has high-efficiency blades. The fans will operate continuously at about 7700 rpm when supplied with electrical power. Thermo switches are installed inside the stators of the recirculation fans. If the temperature of the stators gets to 160 DEG.C (320.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F), the thermo switches isolate the electrical supply to the fans. The recirculation fans are installed on vibration-damper mountings, these prevent damage to the aircraft structure, due to fan vibration. Arrows on the fan casing show the direction of airflow through the fan and the direction that the impellor rotates.
The cabin recirculation fans 14HG (15HG) are installed in line with the recirculation ducts. They are powered by a three-phase six-pole induction motor that drives a fan-wheel which has high-efficiency blades. The fans will operate continuously at about 7700 rpm when supplied with electrical power. Thermo switches are installed inside the stators of the recirculation fans. If the temperature of the stators get to 180 DEG.C (356.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F), the thermo switches isolate the electrical supply to the fans. The recirculation fans are installed on vibration-damper mountings, these prevent damage to the aircraft structure, due to fan vibration. Arrows on the fan casing show the direction of airflow through the fan and the direction that the impellor rotates.
The cabin recirculation fans 14HG (15HG) are installed in line with the recirculation ducts. They are powered by a three-phase six-pole induction motor that drives a fan-wheel which has high-efficiency blades. The fans will operate continuously at about 7700 rpm when supplied with electrical power. Thermo switches are installed inside the stators of the recirculation fans. If the temperature of the stators gets to 160 DEG.C (320.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F), the thermo switches isolate the electrical supply to the fans. The recirculation fans are installed on vibration-damper mountings, these prevent damage to the aircraft structure, due to fan vibration. Arrows on the fan casing show the direction of airflow through the fan and the direction that the impellor rotates.
The cabin recirculation fans 14HG (15HG) are installed in line with the recirculation ducts. They are powered by a three-phase six-pole induction motor that drives a fan-wheel which has high-efficiency blades. The fans will operate continuously at about 7700 rpm when supplied with electrical power. Thermo switches are installed inside the stators of the recirculation fans. If the temperature of the stators get to 180 DEG.C (356.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F), the thermo switches isolate the electrical supply to the fans. The recirculation fans are installed on vibration-damper mountings, these prevent damage to the aircraft structure, due to fan vibration. Arrows on the fan casing show the direction of airflow through the fan and the direction that the impellor rotates.
B. Check Valves
A check valve 4020HM (4021HM) is installed downstream of each cabin recirculation fan 14HG (15HG). Two semicircular flaps are installed on a hinge-bar and a spring holds the semicircular flaps in the closed position. Airflow from the cabin recirculation fans 14HG (15HG) will lift the semicircular flaps from their seats. This will permit air to flow through the check valves 4020HM (4021HM) into the ducts. Airflow in the opposite direction through the check valve will push the semicircular flaps back onto their seats which will stop the airflow. An arrow on the check valve casing shows which way air will flow through the check valve.
A check valve 4020HM (4021HM) is installed downstream of each cabin recirculation fan 14HG (15HG). Two semicircular flaps are installed on a hinge-bar and a spring holds the semicircular flaps in the closed position. Airflow from the cabin recirculation fans 14HG (15HG) will lift the semicircular flaps from their seats. This will permit air to flow through the check valves 4020HM (4021HM) into the ducts. Airflow in the opposite direction through the check valve will push the semicircular flaps back onto their seats which will stop the airflow. An arrow on the check valve casing shows which way air will flow through the check valve.
C. Recirculation Filter
Two recirculation filters 4012HM (4013HM) are installed, one upstream of each recirculation fan 14HG (15HG). Each consists of a multi-layer glassfiber filter-cartridge, installed inside a perforated Carbon Fiber Reinforced Plastic (CFRP) cylinder. The complete filter unit is installed in an open frame type housing 4010HM (4011HM) made of aluminum. The filter unit is secured in position with an adjustable flange at one end of the housing.
Two recirculation filters 4012HM (4013HM) are installed, one upstream of each recirculation fan 14HG (15HG). Each consists of a multi-layer glassfiber filter-cartridge, installed inside a perforated aluminium cylinder. The complete filter unit is installed in an open frame type housing 4010HM (4011HM) made of aluminum. The filter unit is secured in position with an adjustable flange at one end of the housing.
Two recirculation filters 4012HM (4013HM) are installed, one upstream of each recirculation fan 14HG (15HG). Each consists of a multi-layer glassfiber filter-cartridge, installed inside a perforated Carbon Fiber Reinforced Plastic (CFRP) cylinder. The complete filter unit is installed in an open frame type housing 4010HM (4011HM) made of aluminum. The filter unit is secured in position with an adjustable flange at one end of the housing.
Two recirculation filters 4012HM (4013HM) are installed, one upstream of each recirculation fan 14HG (15HG). Each consists of a multi-layer glassfiber filter-cartridge, installed inside a perforated aluminium cylinder. The complete filter unit is installed in an open frame type housing 4010HM (4011HM) made of aluminum. The filter unit is secured in position with an adjustable flange at one end of the housing.
(1) Normal Operation
On the overhead panel 22VU, the CAB FANS pushbutton switch 4HG operates the cabin recirculation fans 14HG (15HG). The switch supplies 28 V DC from the normal busbar 101PP (204PP) through two circuit breakers 2HG (11HG) to two power relays 5HG (6HG). The power relays energize the cabin fans with 115 VAC from the normal busbar 1 and 2 101XP (202XP) through the two circuit breakers 1HG (3HG).
On the overhead panel 22VU, the CAB FANS pushbutton switch 4HG operates the cabin recirculation fans 14HG (15HG). The switch supplies 28 V DC from the normal busbar 101PP (204PP) through two circuit breakers 2HG (11HG) to two power relays 5HG (6HG). The power relays energize the cabin fans with 115 VAC from the normal busbar 1 and 2 101XP (202XP) through the two circuit breakers 1HG (3HG).
(2) Malfunction Detection
OVERHEAT thermo-switches operate if the stator temperature of the recirculation fans 14HG (15HG) goes up to 160 DEG.C (320.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F). They will remove the ground from the power relays 5HG (6HG), the fans will stop and the fan fault relays 10HG (9HG) will open. The fan fault relays signal the Centralized Fault Display System (CFDS) and the Electronic Centralized Aircraft Monitoring (ECAM) system. To start the cabin fans again you must push the CAB FANS switch twice, once to switch OFF and once to switch ON. You must find and repair the fault before you do this.
OVERHEAT thermo-switches operate if the stator temperature of the recirculation fans 14HG (15HG) goes up to 160 DEG.C (320.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F). They will remove the ground from the power relays 5HG (6HG), the fans will stop and the fan fault relays 10HG (9HG) will open. The fan fault relays signal the Centralized Fault Display System (CFDS) and the Electronic Centralized Aircraft Monitoring (ECAM) system. To start the cabin fans again you must push the CAB FANS switch twice, once to switch OFF and once to switch ON. You must find and repair the fault before you do this.
(3) Malfunction Detection
OVERHEAT thermo-switches operate if the stator temperature of the recirculation fans 14HG (15HG) goes up to 180 DEG.C (356.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F). They will remove the ground from the power relays 5HG (6HG), the fans will stop and the fan fault relays 10HG (9HG) will open. The fan fault relays signal the Centralized Fault Display System (CFDS) and the Electronic Centralized Aircraft Monitoring (ECAM) system. To start the cabin fans again you must push the CAB FANS switch twice, once to switch OFF and once to switch ON. You must find and repair the fault before you do this.
OVERHEAT thermo-switches operate if the stator temperature of the recirculation fans 14HG (15HG) goes up to 180 DEG.C (356.00 DEG.F) +/- 8 DEG.C (46.40 DEG.F). They will remove the ground from the power relays 5HG (6HG), the fans will stop and the fan fault relays 10HG (9HG) will open. The fan fault relays signal the Centralized Fault Display System (CFDS) and the Electronic Centralized Aircraft Monitoring (ECAM) system. To start the cabin fans again you must push the CAB FANS switch twice, once to switch OFF and once to switch ON. You must find and repair the fault before you do this.
B. Controls and Indications
If a recirculation fan fails, the recirculation fan control circuit transmits signals to the Centralized Fault Display System (CFDS) and to the Electronic Centralized Aircraft Monitoring (ECAM) for display after flight. The ECAM will give an immediate display only if both fans fail.
If a recirculation fan fails, the recirculation fan control circuit transmits signals to the Centralized Fault Display System (CFDS) and to the Electronic Centralized Aircraft Monitoring (ECAM) for display after flight. The ECAM will give an immediate display only if both fans fail.