APU BLEED AIR SUPPLY AND CROSSBLEED SYSTEMS - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General
The aircraft has an Auxiliary Power Unit (APU) bleed-air supply and a crossbleed system installed in the AFT and Mid fuselage.
The load compressor of the APU supplies the APU bleed air to the distribution system. The supply of the APU bleed air is controlled by the APU bleed load valve. When the APU bleed load valve is in the open position the Pressure Regulator Valves (PRV) of the engines close, and shut off the engine bleed-air supply. Thus the distribution system supplies the APU bleed-air to the user systems. It is not necessary to regulate the temperature, pressure and flow of the APU bleed-air because they agree with the user demand.
The crossbleed system connects the left and right wing supply ducts. The left and right bleed-air systems work in correlation. A crossbleed valve isolates them from each other.

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2. Component Location

Component Location - Cockpit Indications ** ON A/C NOT FOR ALL

Bleed System Equipment in the Avionics Compartment - Compartment Location ** ON A/C NOT FOR ALL

Component Location - Fuselage ** ON A/C NOT FOR ALL

APU Bleed Air Duct - Component Location ** ON A/C NOT FOR ALL

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
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1HA1	BMC-1	95VU	121	36-11-34
1HA2	BMC-2	96VU	122	36-11-34
5HV	P/BSW-AIR COND/APU BLEED	30VU	210	36-12-00
6HV	CROSSBLEED VALVE		191	36-12-52
8LP	BOARD-ANN LT TEST & INTFC	70VU	126	33-14-33
59KD	ELECTRONIC CONTROL BOX		152	49-61-34
7260HM	CHECK VALVE-APU BLEED		152	36-12-51
7265HM	BELLOWS C70-C71		311	36-12-42

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3. System Description

APU Bleed Control Valve - Electrical Schematic ** ON A/C NOT FOR ALL

Crossbleed Valve - Electrical Schematic ** ON A/C NOT FOR ALL

You can use the APU to supply bleed-air to the user systems, while on the ground and during flight.
The APU can supply bleed-air during the climb of the aircraft from the ground to an altitude of 20,000 ft.(6096 m). The APU has a APU bleed load valve and a surge control valve. The APU supplies the bleed-air to the user systems when the APU bleed load valve is in the open position. The supply of the bleed-air is in accordance with demand of the user systems.
The APU bleed-air pressure has a set tolerance independent of the bleed-air flow. The pressure of the APU bleed-air is kept in its set tolerance by the surge control valve. The APU Electronic Control Box (ECB) 59KD receives the signals of the bleed-air demand. The ECB 59KD monitors the bleed-air supply and also controls the APU bleed load valve and the surge control valve.
The APU bleed-air duct connects the APU to the crossbleed duct. A check valve installed in the APU bleed-air duct protects the APU when a different source supplies bleed air with a higher pressure. The crossbleed duct is in the unpressurized area and connects the left and right bleed-air systems. The crossbleed duct has a crossbleed valve which controls the bleed-air supply to the left and right bleed-air systems. When the engine Pressure Regulator Valves (PRV) close, the crossbleed valve opens automatically when the APU supplies the bleed-air.
The crossbleed valve is an electrical shut-off valve controlled by the Bleed-Air Monitoring Computer (BMC) for the automatic operation. You can also operate it manually from the cockpit.

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4. Power Supply

APU Bleed Control Valve - Electrical Schematic ** ON A/C NOT FOR ALL

Crossbleed Valve - Electrical Schematic ** ON A/C NOT FOR ALL

The DC electrical system of the aircraft provides the APU bleed-air supply and the crossbleed system with electrical power.
The battery bus 301PP supplies 28VDC via the circuit breaker 2HV and the selector switch 3HV to the secondary motor of the crossbleed valve. The normal bus 206PP supplies 28VDC via the circuit breaker 1HV, the selector switch 3HV and the crossbleed valve auto control relay 4HV to the primary motor of the crossbleed valve 6HV.

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5. Interfaces
Signal directions

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FROM TO CHAPTER REF.

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APU Pressure and 36-21-00

Temperature

Monitoring

Ducts Manifold Air 36-22-00

Leak Detec-

tion

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6. Component Description

APU Bleed Load Valve ** ON A/C NOT FOR ALL

APU Bleed Load Valve - Schematic ** ON A/C NOT FOR ALL

APU Bleed Check Valve ** ON A/C NOT FOR ALL

A. Valves in the APU Bleed Air Supply and Crossbleed Systems

(1) APU Bleed Load Valve

APU Bleed Load Valve ** ON A/C NOT FOR ALL

The APU bleed load valve has:

A valve flow section
Two position indicator switches and a visual position indicator
A pneumatic actuator and an actuator cover
A solenoid valve assembly.

(a) For detailed description refer to 49-51-00.

(2) APU Bleed Check Valve 7260HM

(a) The APU bleed check valve is a 101.6 mm (4.0 in.) dia. flapper-type air valve. The main components of the valve are:

The valve housing
The valve flaps
The shaft
The spring (low force).
The low-forced spring holds the valve flaps in the closed position. The valve flaps open when the differential pressure is at approximately 0.0025 bar (0.0363 psi).

B. Crossbledd Valve 6HV

Crossbleed Valve ** ON A/C NOT FOR ALL

Crossbleed Valve - Schematic and Logic ** ON A/C NOT FOR ALL

(1) The crossbleed valve is a butterfly-type valve with a diameter of 114.3 mm (4.5 in.).
The main components of the valve are:

The valve body
The butterfly plate
The double motor actuator
The manual override lever.
The double motor actuator has two electrical motors which are designated as the motor 1 and motor 2. These two motors work independently. The motors open and close the valve, of which one motor controls the automatic and the other the manual operation. A brake system in each motor locks the butterfly plate in position when the electrical power supply stops.
When the valve is in its fully open or closed position, limit switches in the actuator automatically stop the electrical power supply to the motors.
The valve also has a manual override lever which permits the operation of the butterfly plate without electrical power.

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7. Operation/Control and Indication

Component Location - Cockpit Indications ** ON A/C NOT FOR ALL

A. APU Bleed-Air Supply-System

APU Bleed indicating ** ON A/C NOT FOR ALL

(1) Start procedure of APU Bleed-Air Supply
The start sequence of the APU is complete when the APU acquires 95% speed (Ref. AMM 49-42-00).
Above the acquired 95% speed the APU is obtainable for the supply of bleed-air and electrical power.
An ECB 59KD logic, permits an APU speed decrease to 88% during normal APU operation before it automatically stops the bleed air.
Information on the ECAM and the overhead panel shows that the APU is available :

On the EWD, (the green APU AVAIL indication comes on)
On the APU page of the SD, (the green AVAIL indication comes on)
On the APU overhead panel 25VU, (the green AVAIL legend on the APU START P/ BSW 2KA comes on.

When the APU is available you can push the APU BLEED P/BSW on the overhead panel 25VU to start the APU bleed-air supply.
When you push the APU BLEED P/BSW :

The blue ON legend on the P/BSW comes on
The P/BSW sends a signal to the BMC
The BMC starts a test of the sensing elements on the APU bleed-air duct and the left wing bleed-air ducts.
If the test is correct the BMC tells the ECB to open the APU bleed load valve.

NOTE: If the BMC 1 finds a leak in the APU bleed-air ducts, while there is a Main Engine Start (MES) signal from the engines, it ignores the leak signal and tells the ECB to open the APU bleed load valve.

(2) Stop of the APU Bleed-Air Supply
To stop the APU bleed-air supply you push the APU BLEED P/BSW again:

The blue ON legend on the APU BLEED P/BSW goes off
The APU BLEED P/BSW removes the ground signal from the BMCs
The BMCs send an OFF signal to the ECB
The ECB stops the supply of electrical power to the solenoid of the APU bleed load valve
The APU bleed load valve closes and stops the bleed air supply
On the BLEED and APU pages of the SD, the green APU bleed-valve symbol is shown in the closed position.

NOTE: If an APU emergency shutdown or an APU automatic shutdown occurs, the APU bleed air supply stops automatically.

(3) Leak Detection
When an overheat sensing element finds a leak:

The BMCs receive a leak signal
The BMCs prepare this signal and send an OFF signal to the ECB
The ECB removes the electrical power from the APU bleed-valve solenoid
The APU bleed valve closes and stops the bleed air supply
The amber FAULT legend in the APU BLEED P/BSW comes on
The amber MASTER CAUT lights come on
A single chime is heard
On the EWD:
AIR
APU BLEED LEAK
- APU BLEED .......................OFF
is shown.
On the BLEED and APU pages of the SD, the APU bleed-valve symbol is shown in the closed position.

When you push the APU BLEED P/BSW:

The ON legend in the APU BLEED P/B goes off,
On the EWD:
STATUS
INOP SYS
APU LEAK
is shown.

B. Crossbleed System

Crossbleed Valve - Schematic and Logic ** ON A/C NOT FOR ALL

Crossbleed Valve - Indicating ** ON A/C NOT FOR ALL

A crossbleed valve is installed in the crossbleed duct in the unpressurized area. The crossbleed valve is equipped with two electrical motors which can both actuate the butterfly plate in the opening or closing positions. One motor is used in the automatic mode, the other in the manual mode. Each motor includes a 'brake system' which locks the butterfly in position if the electrical power supply is cut off.

(1) Automatic Control
The crossbleed valve selector-switch 3HV is usually in the AUTO position. In this position the coil of the crossbleed-valve auto-control relay 4HV is connected to the normal bus 206PP.
When you push the APU BLEED pushbutton-switch 5HV to the ON position the BMCs send a ground signal to the crossbleed-valve auto-control relay 4HV if:

The APU bleed load valve is in the fully open position
There is no leak warning (the leak warning will be ignored during the main engine start).

The crossbleed-valve auto-control relay 4HV supplies electrical power to the crossbleed valve motor 1 and the crossbleed valve opens.
On the BLEED page of the SD the green crossbleed-valve symbol is shown in the open position.

(2) Manual Control
When you set crossbleed-valve selector-switch 3HV to the OPEN position:

The motor 2 opens the crossbleed-valve
On the BLEED page of the SD, the green crossbleed-valve symbol is shown in the open position.

You must only use this procedure in the subsequent cases:

The cross supply of the air-conditioning packs (the left engine supplies air to the right pack or the right engine supplies air to the left pack)
The start of an engine with bleed air from an engine on the other wing (but not during flight. Start by self-rotation is possible)
An engine bleed-air failure and the wing anti-ice condition
Start of the right engine on the ground through the ground connectors or with the APU bleed-air supply.

When you set crossbleed-valve selector-switch 3HV to the SHUT position:

The motor 2 closes the crossbleed-valve
On the BLEED page of the SD, the green crossbleed-valve symbol is shown in the closed position.

(3) Incorrect Operation
If the crossbleed valve does not open or close correctly:

The amber MASTER CAUT lights come on
A single chime is heard
On the EWD:
AIR
X BLEED FAULT
X BLEED ......................MAN CTL
WING A.ICE .......................OFF
AVOID ICING CONDITIONS
is shown.
If the auto-opening of the crossbleed valve is defective, the EWD also shows:
STATUS
X BLEED MAN CTL
If the crossbleed valve does not operate the EWD shows:
STATUS
INOP SYS
X BLEED

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8. Bite Test
You start the test of the pneumatic system from the MCDU in the cockpit. The MCDU shows the defective Line Replaceable Units (LRU) and other information about the system. The Centralized Fault Display System (CFDS) sends this information to the MCDU. The BMC send the information about the pneumatic system to the CFDS.
The subsequent LRU and system data are monitored:

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| BITE TEST

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! X FEED V (6HV) CKT ! 36-12-00 ! ACCIDENTAL OPENING OR ! 1 !

! ! ! CLOSURE OF VALVE IN AUTO ! !

! ! ! MODE ! !

! ! ! ! !

! X FEED V (6HV) CKT ! 36-12-00 ! LOSS OF MANUAL MODE OF ! 1 !

! ! ! CLOSURE AND OPENING ! !

! ! ! CONTROL ! !

! ! ! ! !

! X FEED V (6HV) CKT ! 36-12-00 ! DISAGREE SWITCH FO-FC ! 3 !

[Rev.10 from 2021] 2026.04.01 01:14:16 UTC