TOILET SYSTEM - DESCRIPTION AND OPERATION

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1. General
The toilet system moves waste material and liquids to a waste tank.
The toilet system is a vacuum type and uses potable water for flushing. The waste is collected in one waste holding tank. When the tank is full, a liquid level sensor (which has more importance) stops the system operation. If the liquid level sensor becomes defective, the liquid level transmitter stops the system operation.

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2. Component Location

Toilet System - Component Location ** ON A/C NOT FOR ALL

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
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21DV	NIPPLE ASSY-LAV. DRAIN		172	30-72-52
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37MG	GENERATOR,VACUUM	161DW	172	38-31-00
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37MG	GENERATOR,VACUUM		172	38-31-00
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31MG	CONTROLLER VACUUM SYS	162DW	172	38-31-34
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36MG	RELAY	161DW	172	38-31-36
38MG	RELAY-FAN PHASE OFF	2001VU	263	38-31-00
40MG	XMTR-LEVEL	162DW	172	38-31-62
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41MG	SENSOR,LEVEL	161DW	172	38-31-63
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41MG	SENSOR,LEVEL		172	38-31-63
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43MG	SWITCH,ALTITUDE PRESS	312AR	312	38-31-69
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44MG	SW-SVCE PNL		172	38-31-13
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50MG4	TOILET UNIT LAV.E		262	38-31-00
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50MG1	TOILET UNIT LAV.A		221	38-31-00
50MG2	TOILET UNIT LAV.D		261	38-31-00
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50MG8	TOILET UNIT LAV.M AFT RH		252	38-31-00
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50MG13	TOILET UNIT LAV.GS		261	38-31-00
50MG14	TOILET UNIT LAV.FS		261	38-31-00
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51MG2	TOILET UNIT LAV.L AFT LH		254	38-31-00
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3300MM	WASTE TANK	162DW	172	38-31-61
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3341MM	CONTROL LEVER - ASSEMBLY	172AR	172	38-31-73
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3302MM	WATER SEPERATOR		172	38-31-67
3320MM	CHECK VALVE		172	38-31-65
3322MM	CHECK VALVE	162DW	172	38-31-76
3323MM	CHECK VALVE	162DW	172	25-10-00
3340MM	WASTE DRAIN VALVE	162DW	172	38-31-71
3345MM	WASTE LINE DRAIN V.	172AR	172	38-31-72
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3341MM	CONTROL LEVER - ASSEMBLY		172	38-31-73
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3300MM	WASTE TANK		172	38-31-61

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3. System Description

Vacuum Toilet System - Schematic ** ON A/C NOT FOR ALL

Toilet System - Component Location ** ON A/C NOT FOR ALL

The system uses potable water from the aircraft pressurized water system to flush the toilet. A vacuum drain removes waste from the toilet bowl to an underfloor waste holding tank. An electronic vacuum system controller controls the system and related electronic components.
The toilet system is divided into:

The cabin installation
The cabin underfloor installation.

The cabin installation has a single toilet assembly in each lavatory. The cabin underfloor installation has:

A waste holding tank assembly
A Liquid Level Transmitter (LLT) (tank mounted)
A Liquid Level Sensor (LLS) (tank mounted)
A vacuum generator
A Vacuum System Controller (VSC)
A check valve (vacuum pressure)
An altitude pressure switch
A check valve (installed in each flush Line of the waste tank)
A waste drain valve
A waste service panel
The pipelines (overfloor and underfloor).

Vacuum Toilet System - Schematic ** ON A/C NOT FOR ALL

Toilet System - Component Location ** ON A/C NOT FOR ALL

The system uses potable water from the aircraft pressurized water system to flush the toilet. A vacuum drain removes waste from the toilet bowl to an underfloor waste holding tank.
The vacuum toilet system is connected to the CIDS system which controls the system function and related electronic components.
The toilet system is divided into:

The cabin installation
The cabin underfloor installation.

The cabin installation has a single toilet assembly in each lavatory.
The cabin underfloor installation has:

A waste holding tank assembly
A Liquid Level Sensor (LLS) (tank mounted)
A Liquid Level Transmitter (LLT) (tank mounted)
A vacuum generator
A check valve (vacuum pressure)
A check valve (installed in each flush line of the waste tank)
A waste drain valve
A waste service panel
The pipelines (overfloor and underfloor).

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4. Component Description

A. Toilet Assembly
Vacuum Toilet Assembly 50MG

Vacuum Toilet Assembly 50MG ** ON A/C NOT FOR ALL

Each toilet assembly has:

A bowl and spray ring
A water (rinse) valve and screen
An anti-syphon valve
A flush valve
A flush control unit
A support frame.

Bowl and Spray Ring
The bowl is made of stainless-steel and has a non-stick layer on its inside surface. The spray ring is attached to the top of the bowl and connected to the anti-syphon valve.
Water Valve and screen (Rinse Valve)
The water (rinse) valve is a solenoid controlled plunger type. It is connected electrically to the flush control unit. It has an integral water inlet fitting and a finger-type stainless steel-screen. The outlet of the valve is connected to the anti-syphon valve.
Anti-Syphon Valve
The anti-syphon valve is installed above the toilet bowl and is connected to the water valve and the spray ring. It lets water flow only in the direction of the spray ring and returns back-water to the bowl.
Flush Valve (Rotary Gate Type)
The flush valve is a motor operated gate valve. A duct with 130 deg. angle connects the flush valve to the toilet bowl. The flush valve body and the rotary disc are made of stainless steel. The valve is fully open during the flush cycle. The waste flows through a 2.0 in. (50.8 mm) dia. tube. The rotary disc closes and seals the tube between the flush cycles. The flush control unit controls the flush valve operation.
Flush Control Unit
The flush control unit is an electronic assembly installed on the support frame of the toilet assembly. It is connected electrically to the:

Flush switch
Water (rinse) valve and screen
Flush valve
Vacuum system controller.

The unit controls the time and sequence of the toilet operation during the flush cycle. Built-in-test Equipment (BITE), monitors the operation of the water valve, flush valve and its internal control board circuitry. Faults are transmitted to the vacuum system controller.
Vacuum Toilet Assembly 50MG

Vacuum Toilet Assembly 50MG ** ON A/C NOT FOR ALL

Each toilet assembly has:

A bowl and spray ring
A water (rinse) valve and screen
An anti-syphon valve
A flush valve
A flush control unit
A support frame.

Bowl and Spray Ring
The bowl is made of stainless-steel and has a non-stick layer on its inside surface. The spray ring is attached to the top of the bowl and connected to the anti-syphon valve.
Water Valve and screen (Rinse Valve)
The water (rinse) valve is a solenoid controlled plunger type. It is connected electrically to the flush control unit. It has an integral water inlet fitting and a finger-type stainless steel-screen. The outlet of the valve is connected to the anti-syphon valve.
Anti-Syphon Valve
The anti-syphon valve is installed above the toilet bowl and is connected to the water valve and the spray ring. It lets water flow only in the direction of the spray ring and returns back-water to the bowl.
Flush Valve (Rotary Gate Type)
The flush valve is a motor operated gate valve. A duct connects the flush valve to the toilet bowl. The flush valve body is made of composite material and the rotary disc is made of stainless steel. The valve is fully open during the flush cycle. The waste flows through a 2.0 in. (50.8 mm) dia. tube. The rotary disc closes and seals the tube between the flush cycles. The flush control unit controls the flush valve operation.
Flush Control Unit
The flush control unit is an electronic assembly installed on the support frame of the toilet assembly. It is connected electrically to the:

Flush switch
Water (rinse) valve
Flush valve
DEU B (CIDS).

The FCU controls the time and sequence of the toilet operation during the flush cycle. Built-In-Test Equipment (BITE), monitors the operation of the water valve, flush valve and its internal control board circuitry. Faults are transmitted to the CIDS.
Vacuum Toilet Assembly 50MG

Vacuum Toilet Assembly 50MG ** ON A/C NOT FOR ALL

Each toilet assembly has:

A bowl and spray ring
A water (rinse) valve and screen
An anti-syphon valve
A flush valve with an integrated flush control unit (FCU)
A support frame.

Bowl and Spray Ring
The bowl is made of stainless-steel and has a non-stick layer on its inner surface. The spray ring is attached to the top of the bowl and connected to the anti-syphon valve.
Water Valve and Screen (Rinse Valve)
The water (rinse) valve is a solenoid-controlled plunger type. It is connected electrically to the flush control unit. It has an integral water inlet fitting and a finger-type screen made of stainless steel. The outlet of the valve is connected to the anti-syphon valve.
Anti-Syphon Valve
The anti-syphon valve is installed above the toilet bowl and is connected to the water valve and the spray ring. It lets water flow only in the direction of the spray ring and returns back-water to the bowl.
Flush Valve (Rotary Gate Type) with Integrated Flush Control Unit
The flush valve is a motor-operated gate valve. A duct connects the flush valve to the toilet bowl. The flush valve body is made of composite material and the rotary disc is made of stainless steel. The flush valve is fully open during the flush cycle. Then, the waste flows through a 2.0 in. (50.8 mm) dia. waste water tube. Between the flush cycles, the rotary disc is closed and seals the waste water tube.
Integral to the flush valve is the flush control unit. It is a modular electronic assembly and controls the operation of the flush valve. The flush control unit is installed in the housing of the flush valve motor and gear train. It is connected electrically to:

The flush switch
The water (rinse) valve
The flush valve
The DEUB (CIDS)

The FCU controls the time and the sequence of the toilet operation during the flush cycle. Built-In-Test Equipment (BITE) monitors the operation of the water valve and of the flush valve and its internal control board circuitry. Faults are transmitted to the CIDS.
Vacuum Toilet Assembly 50MG

Vacuum Toilet Assembly 50MG ** ON A/C NOT FOR ALL

Each toilet assembly has:

A bowl and rinse ring
A water (rinse) valve and screen
An anti-siphon valve
A flush valve with an integrated flush control unit (FCU)
A support frame.

Bowl and Rinse Ring
The bowl is made of high density polyethylene (HPDE) and has a non-stick layer on its inner surface. The rinse ring is attached to the top of the bowl and connected to the anti-siphon valve.

Water Valve and Screen (Rinse Valve)
The water (rinse) valve is a solenoid-controlled plunger type. It is connected electrically to the flush control unit. It has an integral water inlet fitting and a finger-type screen. The outlet of the valve is connected to the anti-siphon valve.

Anti-Siphon Valve
The anti-siphon valve is installed above the toilet bowl and is connected to the water valve and the rinse ring. It lets water flow only in the direction of the rinse ring and returns back-water to the bowl.

Flush Valve (Arc-Shaped Gate Type) with Integrated Flush Control Unit
The flush valve is a motor-operated gate valve. A duct connects the flush valve to the toilet bowl. The flush valve is fully open during the flush cycle. Then, the waste flows through a 2.0 in. (50.8 mm) dia. waste water tube. Between the flush cycles, the rotary disc closes and seals the waste water tube.

Integral to the flush valve is the Flush Control Unit (FCU). It is a modular electronic assembly and controls operation of the flush valve. The flush control unit is installed in the housing of the flush valve motor and gear train. It is connected electrically to:

The flush switch
The water (rinse) valve
The flush valve
The DEUB (CIDS)
The maintenance switch.

B. Vacuum Toilet System - Underfloor Components

Underfloor Components ** ON A/C NOT FOR ALL

Waste Holding Tank ** ON A/C NOT FOR ALL

(1) Waste Holding Tank 3300MM
The waste holding tank is installed on the right of the aircraft under the floor between FR65 and FR68. The tank has:

A water separator
A liquid level transmitter
A liquid level sensor
The waste inlets
A waste outlet
Two rinse connections.

The tank is a filament wound cylindrical vessel with a toilet waste capacity of 170 l (44.9 USgal).

(a) Water Separator 3302MM
The water separator is installed on the top of the waste holding tank and has an upper and a lower section. You must take the two sections apart for servicing of the filter in the lower section. The upper section has an air outlet for the vacuum line.

(b) Liquid Level Transmitter 40MG
The Liquid Level Transmitter (LLT) is installed in the bottom of the waste holding tank. It monitors the contents level in the waste holding tank and sends an analog signal to the Vacuum System Controller (VSC).

(c) Liquid Level Sensor 41MG
The Liquid Level Sensor (LLS) is installed in the upper section of the waste holding tank. It sends a signal to the Vacuum System Controller (VSC) when the tank is full. The VSC prevents further toilet flush operation.

(2) Vacuum Generator 37MG
The vacuum generator is installed on the right of the aircraft under the floor between FR68 and FR69. It is a self-contained centrifugal unit with thermal overload protection. The generator air inlet is connected to the water-separator air-outlet. The generator air outlet is connected to the aircraft overboard ventline. The generator gives the necessary differential pressure in the waste tank to move the waste from the bowl to the tank. The vacuum generator is electrically connected to the aircraft power-circuit.

(3) Altitude Pressure Switch 43MG
The altitude pressure switch is installed between FR71 and FR72. The switch is connected electrically to the Vacuum System Controller (VSC). It gives an electrical signal to the VSC which starts or stops the operation of the vacuum generator.

(4) Vacuum System Controller 31MG
The Vacuum System Controller (VSC) is installed on the right of the lower section of the fuselage between FR62 and FR63. The VSC is an electronic unit which has a Built In Test Equipment (BITE). The VSC is connected electrically to the aircraft power circuit. It is also electrically connected to:

The flush control unit(s)
The liquid level transmitter
The liquid level sensor
The altitude pressure switch
The Forward Attendant Panel (FAP)
Centralized Fault Display System (CFDS) via ARINC 429 data bus.

The VSC gives the CFDS failure data of the vacuum toilet system.
The VSC also gives a RS 232-C interface for failure data for shop maintenance.

(5) Check Valve 3320MM (vacuum pressure)
The check valve is installed in the waste holding tank air outlet-line and parallel to the vacuum generator line. It lets air flow from the tank to the overboard vent line and stops opposite airflow.

(6) Check Valve 3322MM/3323 (tank rinse line)
The check valve is installed in the rinse line of the waste holding tank. It lets water flow in one direction only. There are two rinse inlets on the upper side of the tank which are equipped with one check valve each.

(7) Waste Drain Valve 3340MM
The waste drain valve is installed in the waste holding tank drain line. It is a ball type manually operated shutoff valve.

(8) Waste Holding Tank 3300MM
The waste holding tank is installed on the right of the aircraft under the floor between FR65 and FR68. The tank has:

A water separator
A liquid level transmitter
A liquid level sensor
The waste inlets
A waste outlet
Two rinse connections.

The tank is a filament wound cylindrical vessel with a toilet waste capacity of 170 l (44.9 US gal).

(c) Liquid Level Sensor 41MG
The Liquid Level Sensor (LLS) is installed in the upper section of the waste holding tank. It sends a signal to the CIDS system when the tank is full to prevent further toilet flush operation.

(9) Vacuum Generator 37MG
The vacuum generator is installed on the right of the aircraft under the floor between FR68 and FR69. It is a self-contained centrifugal unit with thermal overload protection. The generator air inlet is connected to the water-separator air-outlet. The generator air outlet is connected to the aircraft overboard vent line. The generator gives the necessary differential pressure in the waste tank to move the waste from the bowl to the tank:

On the ground
In flight at low flight altitude.

The vacuum generator is electrically connected to the aircraft power-circuit and is controlled though the DEU B and the DIR 1-2.

(10) Check Valve 3320MM (vacuum pressure)
The check valve is installed in the waste holding tank air outlet-line and parallel to the vacuum generator line. It lets air flow from the tank to the overboard vent line and stops opposite airflow.

(11) Check Valve 3322MM/3323MM (tank rinse line)
The check valve is installed in the rinse line of the waste holding tank. It lets water flow in one direction only. There are two rinse inlets on the upper side of the tank which are equipped with one check valve each.

(12) Waste Drain Valve 3340MM
The waste drain valve is installed in the waste holding tank drain line. It is a ball type manually operated shutoff valve.

(13) Waste Holding Tank 3300MM
The waste holding tank is installed on the right of the aircraft below the floor between FR65 and FR68. The tank has:

A water separator
A liquid level transmitter
A liquid level sensor
The waste inlets
A waste outlet
Two rinse connections.

The tank is made of composite materials with a tank capacity of 66.04 US gal (250 l).

(a) Water Separator 3302MM
The water separator is installed on the top of the waste holding tank and has an upper and a lower section. You must get the two sections apart for servicing of the filter in the lower section. The upper section has an air outlet for the vacuum line.

(14) Vacuum Generator 37MG
The vacuum generator is installed on the right of the aircraft below the floor between FR68 and FR69. It is a self-contained centrifugal unit with thermal overload protection. The generator air inlet is connected to the water-separator air outlet. The generator air outlet is connected to the aircraft overboard ventline. The generator gives the necessary differential pressure in the waste tank to move the waste from the bowl to the tank:

On the ground
In flight at low flight altitude.

The vacuum generator is electrically connected to the aircraft power circuit and is controlled though the DEU B and the DIR 1-2.

(15) Check Valve 3320MM (vacuum pressure)
The check valve is installed in the waste holding tank air outlet-line and parallel to the vacuum generator line. It lets air flow from the tank to the overboard vent line and stops opposite airflow.

(16) Check Valve 3322MM/3323MM (tank rinse line)
The check valve is installed in the rinse line of the waste holding tank. It lets water flow only in one direction. There are two rinse inlets on the upper side of the tank which have one check valve each.

(17) Waste Drain Valve 3340MM
The waste drain valve is installed in the waste holding tank drain line. It is a ball type manually operated shutoff valve.

C. Toilet Service Panel(s)

Toilet Service Panel

The service panel is installed on the right of the lower fuselage between FR65 and FR66. The panel is for the forward and aft toilets. The panel has:

A waste holding tank drain connection
A waste holding tank rinse connection
An actuation unit for the waste drain valve
A limit switch 44MG.

A placard is installed on each of the connections to identify operation and use. To close the service panel door, the drain handle and blanking caps must be in the closed position.

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5. Operation

DEU B - Signal Interface ** ON A/C NOT FOR ALL

Vacuum Toilet System - Electrical Schematic ** ON A/C NOT FOR ALL

Vacuum System Control - Signal Interface ** ON A/C NOT FOR ALL

Vacuum Toilet System - Electrical Schematic ** ON A/C NOT FOR ALL

A. Toilet Assembly 50MG

(1) General
The toilet assembly has a Flush Control Unit (FCU) which controls its operation. Potable water from the aircraft pressurized water system from between 1.72 bar (25 psi) to 1.93 bar (28 psi) flushes the toilet bowl. Differential pressure between the waste tank and cabin moves water and waste from the bowl into the waste holding tank.

(2) Flush Control Unit

Flush Control Unit - Schematic and Flush Cycle Sequence ** ON A/C NOT FOR ALL

The time and sequence of the different components is controlled through the Flush Control Unit (FCU), which controls the toilet flush cycle. The FCU BITE monitors the water valve, flush valve and internal control circuitry. If a fault is detected, it is transmitted through the DEU B to DIR 1-2 of the CIDS system.

(a) Flush Cycle Sequence

Flush Control Unit - Schematic and Flush Cycle Sequence ** ON A/C NOT FOR ALL

The flush cycle starts when you push the flush switch, and the FCU starts the flush sequence as follows:

The vacuum generator starts to operate after the operation of the flush switch, (if differential pressure is below 246 mbar (4 psi) during climb and below 203 mbar (3 psi) during the descent) and stays on for approximately 15 seconds.
The water valve opens 1.6 seconds after operation of the flush switch, and stays open for 1.7 seconds. In this time the toilet bowl is rinsed.

The flush valve opens 2.0 seconds after operation of the flush switch, and it stays open for 4 seconds.

The differential pressure now moves the waste from the toilet bowl to the waste holding tank. When the differential pressure is sufficient, the flush cycle will stay the same. But the CIDS will not activate the vacuum generator.

(b) Built-In Test Equipment (BITE)
The BITE of the flush control unit finds the faults of the:

Water valve solenoid
Flush valve motor
Flush valve (limit switch open)
Flush valve (limit switch closed)
Flush control unit.

NOTE: Faults found are transmitted from BITE via the DEU B to the DIR 1-2 of the CIDS system.

(3) General
The toilet assembly has a Flush Control Unit (FCU) which controls its operation. Potable water from the aircraft pressurized water system from between 1.72 bar (25 psi) to 1.93 bar (28 psi) flushes the toilet bowl. Differential pressure between the waste tank and cabin moves water and waste from the bowl to the waste holding tank.

(4) Flush Control Unit

Flush Control Unit - Schematic and Flush Cycle Sequence ** ON A/C NOT FOR ALL

(a) Flush Cycle Sequence

Flush Control Unit - Schematic and Flush Cycle Sequence ** ON A/C NOT FOR ALL

The flush cycle starts when you push the flush switch, and the FCU starts the flush sequence as follows:

The vacuum generator starts to operate after the operation of the flush switch, (on the ground and in flight below 16000 ft.) and stays on for approximatly 15 seconds
The water valve opens 1.6 seconds after operation of the flush switch, and stays open for 1.7 seconds.

In this time the toilet bowl is rinsed.

The flush valve opens 2.2 seconds after operation of the flush switch, and it stays open for 4 seconds.

The differential pressure now moves the waste from the toilet bowl into the waste holding tank. Above 4877 m (16000 ft.) altitude, the flush cycle will stay the same. But the vacuum system controller will remove the electrical power from the vacuum generator and stop the generator operation.

(b) Double Flush
In order to activate a second flush within the same flush cycle, the flush switch has to be pushed again. When the flush switch is pushed between 3 and 8 seconds after the first operation:

The water valve (rinse valve) will open (8 seconds after first operation of the flush switch) for 2.7 seconds
2.2 seconds later the flush valve opens for 4 seconds,
The flush cycle is completed 10 seconds after the second operation of the flush switch.

Water valve solenoid
Flush valve motor
Flush valve (valve open)
Flush valve (valve closed)
Flush control unit.

NOTE: Faults found are transmitted from BITE to the VSC.

B. Depressurization System

(1) The depressurization system (Ref. AMM 38-41-00) is used to quickly depressurize the potable water system for long time parking in cold weather conditions. When the WTR SYSTEM DEPRE switch on the FAP is pressed and the light in the membrane switch is ON:

The vacuum system will not operate and the SYSTEM INOP indication will come on.

(2) The vacuum system will operate again when the WTR SYSTEM DEPRE switch is pressed again and the light is OFF.

(3) The depressurization system (Ref. AMM 38-41-00) is used to quickly depressurize the potable water system for long time parking in cold weather conditions. When the 'WATER DEPRESS' switch on the FAP is pushed and the green light comes on:

the message 'NO WATER PRESSURE' on the aircraft symbol is on.
the message in the list box shows 'VACUUM SYSTEM DISABLED - WATER DEPRESS ACTIVE' comes in view.

(4) The vacuum system will operate again when the 'WATER DEPRESS' switch is pushed again and the green light and messages are off.

C. Vacuum Generator 37MG

(1) The vacuum generator is connected to the aircraft power circuit through the motor starting relay (36MG). The generator operates:

At ground level and up to an altitude of 4877 m (16000 ft.). The altitude pressure switch stays closed and sends an electrical signal to the VSC to operate the vacuum generator.
When the toilet flush switch is operated. The FCU sends an electrical signal to the VSC which energizes the motor starting relay. This supplies power to the vacuum generator.

NOTE: After 15 seconds the motor start relay is isolated and electrical power to the generator is stopped.

(2) Vacuum generator overheat protection:
The VSC monitors the thermal switch circuit (overheat protection) of the vacuum generator. When an overheat occurs the thermal switch opens. This sends an electrical signal to the VSC and stops electrical power to the vacuum generator.

(3) The vacuum generator is connected to the aircraft power circuit through the motor starting relay (36MG). The generator operates:

On ground
If the differential pressure is less than 246 mbar (4 psi) during climb
If the differential pressure is less than 203 mbar (3 psi) during descent.

The different pressure information comes from the SDAC.
When the toilet flush switch is operated:

The FCU sends an electrical signal (through the connected DEU B to the DIR 1-2 of the CIDS) which activates the motor starting relay.

This supplies power to the vacuum generator.

NOTE: After 15 seconds the motor start relay is deactivated and electrical power to the generator is stopped.

(4) Vacuum generator overheat protection:
The DIR 1-2 controls the thermal switch circuit (overheat protection) of the vacuum generator. When an overheat occurs the thermal switch opens. This sends an electrical signal via the DEU B to the DIR 1-2 and stops electrical power to the vacuum generator.

D. Vacuum Toilet System

(1) Altitude Pressure Switch 43MG
The altitude pressure switch is connected electrically to the VSC and operates:

At ground level and altitudes up to 4877 m (16000 ft.) the altitude pressure switch stays closed
Above 4877 m (16000 ft.) the altitude pressure switch stays open
During altitude descent the switch closes at 3658 m (12001 ft.).

The VSC monitors when the altitude pressure switch is open or closed.

(2) System Data Acquisition Concentrators (SDAC)
The SDAC is electrically connected to the CIDS Director 1-2 (refer to as DIR 1-2). The signal from the SDAC is used for altitude operations of the vacuum generator:

During climb the vacuum generator is activated when the differential is less than 246 mbar (4 psi)
During descent the vacuum generator is activated when the differential is less than 203 mbar (3 psi).

The DIR 1-2 monitors the operation of the vacuum generator.

E. Landing Gear Signal
One of the functions of the Landing Gear (LG) signal is to give the indication to the VSC (that the aircraft is on ground and the strut is compressed).
The LG signal is also used as a back up for other primary indications. In general a single LG fault will have no effect on the vacuum waste system.
The VSC will not generate a fault message if the LG signal is faulty, because the VSC BITE does not control the LG signal.
One of the functions of the Landing Gear (LG) signal is to give the indication to the DIR 1-2 (that the aircraft is on ground and the LG is compressed).
The LG signal is also used as a back up for other primary indications. In general a single LG fault will have no effect on the vacuum waste system.
The DIR 1-2 will not generate a fault message if the LG signal is faulty, because the DIR 1-2 BITE does not control the LG signal.

F. Transducer and/or Transmitter

(1) Liquid Level Transmitter 40MG
The LLT gives the waste content level of the waste holding tank from empty to full. It measures the hydrostatic pressure of the tank contents. The LLT is connected electrically to the VSC. It gives the VSC an analog signal for the waste content of the tank. The VSC calculates and transmits the signal to the Forward Attendants Panel (FAP) for waste quantity indication.

(2) Liquid Level Transmitter 40MG
The LLT gives the waste content level of the waste holding tank from empty to full. It measures the hydrostatic pressure of the tank contents. The LLT is connected electrically to the DEU B. It gives the DEU B an analog signal for the waste content of the tank. The DEU B transmits the signal to the DIR 1-2. The signal to the Flight Attendant Panel (FAP) for waste quantity indication comes from the DIR 2 and the DIR 1.

G. Liquid Level Sensor 41MG
The LLS is an ultrasonic type sensor it is connected electrically to the VSC. When the waste holding tank content level is at full, the LLS sends a signal to the VSC. When the VSC receives a tank full signal, (from the LLS) it shuts down the toilet systems and the SYS INOP legend on FAP comes on. Under normal operation the LLS has the priority to transmit tank full to the VSC.

NOTE: The liquid level sensor operates independently of the liquid level transmitter.

The LLS is an ultrasonic type sensor, it is connected electrically to the DEU B. When the waste holding tank content level is at full, the LLS sends a signal to the DEU B. When the CIDS receives a tank full signal, (from the LLS) the DIR shuts down the toilet systems. The signal also goes to the FAP through the DIR 2 and DIR 1 and the message "VACUUM SYSTEM DISABLED - WASTE TANK FULL" comes into view on FAP. Under normal operation the LLS has the priority to transmit tank full to the DEU B.

NOTE: The liquid level sensor operates independently of the liquid level transmitter.

H. Vacuum System Controller 31MG

Vacuum System Controller - Schematic ** ON A/C NOT FOR ALL

The Vacuum System Controller (VSC) functions are:

System control and monitoring
Fault reporting.

The VSC calculates and transmits signals to the FAP to indicate the waste tank levels and reports system defects. The VSC memorizes and also signals the system defects to the ARINC 429 data bus which is connected to the Centralized Fault Display System (CFDS). Defect signals are also sent to a RS 232-C interface for ground maintenance and inspection.

** ON A/C NOT FOR ALL

6. Test

A. System Monitoring and Control

Control System Menu ** ON A/C NOT FOR ALL

Trouble Shooting Data ** ON A/C NOT FOR ALL

Miscellaneous Module ** ON A/C NOT FOR ALL

Control System Menu ** ON A/C NOT FOR ALL

Trouble Shooting Data ** ON A/C NOT FOR ALL

WATER/WASTE Menu Page ** ON A/C NOT FOR ALL

Control System Menu ** ON A/C NOT FOR ALL

Trouble Shooting Data ** ON A/C NOT FOR ALL

WATER/WASTE Menu Page ** ON A/C NOT FOR ALL

BITE Fault Information - Vacuum Toilet System ** ON A/C NOT FOR ALL

(1) Monitoring
The VSC has a Built-In Test Equipment (BITE) which operates in two modes:

The power-up test,
The continuous monitoring.

(a) Power-Up Test

1 The power-up test starts automatically when:

The VSC is energized with 28VDC,
The aircraft is in the ground configuration.

2 The BITE test monitors the internal operation of the VSC which are:

The power supplies,
The microprocessor,
The memories,
The input and output signals.

3 The BITE test monitors if the following external system circuits operate correctly:

The flush control units,
The liquid level transmitter 40MG,
The liquid level sensor 41MG,
The altitude pressure switch 43MG.

4 During the flush cycle the BITE monitors:

The vacuum generator 37MG,
The aircraft power supply 115 V AC (400 Hz).

(b) Results of power-up tests

1 In case of a bite test failure, the VSC will send the failure to the CFDS.

(c) Continuous Monitoring
Continuous monitoring is used on the ground and during flight and makes sure that the system operates correctly.
It monitors:

The VSC internal circuits,
The power supplies,
The microprocessor,
The memories,
The input and output signals,
The system external circuits.

(2) Monitoring
The CIDS has a Built-In Test Equipment (BITE) which operates in two modes for the vacuum toilet system:

The power-up test
The continuous monitoring of the Vacuum System Control Function (VSCF).

(a) Power-Up test

1 Initialization of the power-up test (Ref. AMM 23-73-00).

2 The CIDS monitors if the following external system circuits function correctly:

The flush control units
Liquid level transmitter 40MG
Liquid level sensor 41MG
28VDC
The motor start relay
Waste-service panel-limit switch 44MG.

3 During the flush cycle the BITE monitors:

Vacuum generator 37MG
The aircraft power supply 115VAC (400Hz).

(b) Continuous Monitoring (DIR 1/DIR 2)
Continuous monitoring (VSCF) is used on the ground and during flight and makes sure that the system operates correctly.

The system external circuits of the vacuum toilet system.

(3) Control Function
The control functions of the VSC are:

The normal operation
The failure mode.

(a) Normal Operation

1 When the VSC receives a signal from a FCU:

It stops the operation all other FCU's
Makes an analysis of the altitude pressure switch indication
Starts the vacuum generator if the altitude pressure switch gives a signal low (below 4877 m (16000 ft.))
Stops power supply to the vacuum generator if the altitude pressure switch gives a signal high (above 4877 m (16000 ft.))
Examines for defects in the aircraft power supply 115 V/400 Hz
Examines continuously the vacuum generator for overheat signals during the flush cycle if there is no 115 V/400 Hz defect.

2 The VSC calculates and transmits the signal to the FAP:

To show the level of the waste in the waste holding tank.

3 When the limit switch on the waste service panel indicates OPEN panel and the aircraft is on ground (CFDS):

The VSC stops all toilet operations and the flush signals are ignored
The SYS INOP light on the FAP is switched on.

4 If the LG signal indicates Flight and the waste service panel is open:

The system will not be disabled and it will be able to flush the toilets while the servicing is done.

5 The VSC will not react on a single LG fault, because the VSC BITE does not control the LG signal.

(b) Failure Mode

1 The VSC transmits the system defects to the ARINC 429 data bus.The VSC memorizes the defect signals for ground maintenance and inspection. These signals are:

a The flush control unit defect:

All corresponding toilet operations are stopped and the defective LAV INOP legend on the FAP comes on.

b 115 V AC power supply shutdown (no signal input for at least one second):

The toilet which is in the flush cycle will stop and the VSC will indicate system INOP on the FAP
The VSC will start normal operation again when the power supply has returned for at least 1 second.

c Vacuum generator (overheat) defect:

The VSC stops the power supply to the vacuum generator and the toilet flush cycle stops (on the ground and in flight below 4877 m (16000 ft.)).

2 The VSC will transmit and keep the defect data but the system will operate normally if:

The LLT indicates a full tank (current signal 12.9 mA). and the LLS does not

3 The VSC will stop the system operation and the SYS INOP legend on the FAP comes on if:

The LLS indicates a full tank and the LLT does not.

4 The VSC will stop the system operation and the SYS INOP legend on the FAP comes on if:

The LG falsely indicate ON GROUND
The service panel door falsely indicates door OPEN when the aircraft is in flight.

(4) Vacuum System Control Function (VSCF)
The control functions of the DIR are:

The normal operation
The failure mode.

(a) Normal Operation

1 When the DEU B receives a signal from a FCU:

It sends the signal to the DIR 1-2.

2 The DIR 1-2:

Makes an analysis of the signal from the SDAC
Starts the vacuum generator if the differential pressure signal is less than 246 mbar during climb
Starts the vacuum generator if the differential pressure signal is less than 203 mbar during descent.

3 The DEU B:

Examines for defects in the aircraft power supply 115V/400Hz
Examines continuously the vacuum generator for overheat signals during the flush cycle if there is no 115V/400Hz defect.

4 The DIR calculates and transmits the signal to the FAP:

To show the level of the waste in the waste holding tank.

5 When the limit switch on the waste service panel indicates OPEN panel and the aircraft is on ground (CFDS):

The DEU B stops all toilet operations and the flush signals are ignored
The FAP message on the WATER/WASTE page VACUUM SYSTEM DISABLED-GROUND SERVICING is switched on.

6 The DIR will not react on a single LG fault, because the DIR BITE does not control the LG signal.

(b) Failure Mode

1 The DIR transmits the system defects to the ARINC 429 data bus. The DIR memorizes the defect signals for ground maintenance and inspection. These signals are:

a The flush control unit defect:

The corresponding toilet operations is stopped.

b 115VAC power supply shutdown.

c Vacuum generator (overheat) defect:

The vacuum generator will be disabled after the third detection during one flight leg.

2 The DIR will transmit and keep the defect data but the system will operate normally if:

The LLT indicates a full tank and the LLS does not.

3 The DIR will stop the system operation and the SYS INOP legend on the FAP comes on if:

The LLS indicates a full tank and the LLT does not.

4 The DIR will stop the system operation and the VACUUM SYSTEM DISABLE ON GROUND message on the WATER/WASTE page on the FAP comes on if:

The CFDS falsely indicates ON GROUND
The service panel door falsely indicates door OPEN when the aircraft is in flight.

B. Water System Depressurization

(1) VSC - Water System Depressurization
The vacuum system controller will also let the vacuum SYSTEM INOP light come on:

When the depressurization control switch WTR SYSTEM DEPRE on the FAP is pressed.

(2) When the depressurization control switch 'WATER DEPRESS' on the FAP is pressed:

The DIR will stop the vacuum system operation and the VACUUM SYSTEM DISABLED - WATER DEPRESS ACTIVE message on the WATER/WASTE page on the FAP comes on.
On the aircraft symbol the message NO WATER PRESSURE will also come in view.

(3) Operation Mode - Sensor Failures

(a) If the LLT does not operate:

The system will continue to operate (the VSC monitors the LLS to sense when the waste tank is full).

(b) If the LLS does not operate:

the system will continue to operate (the VSC monitors the LLT to sense when the waste tank is full).

The LG signal is used to give the information ON GRROUND or IN FLIGHT
On the ground the vacuum generator will operate
In flight the vacuum generator is inhibited.

(d) If both the altitude pressure switch and the LG signal falsely indicate high altitude:

The vacuum generator will not work and the toilets will not flush on the ground. The toilets will however work at high altitude because of the cabin differential pressure.

(e) If the LLT and the altitude pressure switch do not operate, the system will continue to operate as follows:

The LLS sends the signal tank full to the VSC.

(f) If the LLS and the altitude pressure switch do not operate, the system will continue to operate as follows:

The LLT sends the signal tank full to the VSC.

(g) Service Door Limit-Switch 44MG Failure (indicates door open)

1 On the ground:

a The system will not operate

b The SYS INOP and the LAV (X) INOP lights on the FAP are ON.

2 In Flight:

a The system will however operate

b In this situation the SYS INOP and the LAV (X) INOP lights will go OFF,

c they will come ON again after the landing.

(h) If the door limit switch 44MG does not operate (indicates door close):

The system will operate on the ground and in the air as normal.
The system will not be disable and you can flush the toilets during ground servicing.

NOTE: If there are three or more sensor failures at one time the system will not operate. But If the LLS and the LLT do not operate, the system will also not operate and the SYS INOP lamp on the FAP comes on.

(4) Operation Mode - Sensor Failures

(a) If the LLT does not operate:

The system will continue to operate (the DIR monitors the LLS to sense when the waste tank is full).

(b) If the LLS does not operate:

The system will continue to operate (the DIR monitors the LLT to sense when the waste tank is full).

(c) If the differential pressure signal (from the SDAC) does not operate, the system will continue to operate as follows:

The CFDS (maintenance phase) signal is used to give the information ON GROUND or IN FLIGHT
On the ground the vacuum generator will operate
In flight the vacuum generator is inhibited.

(d) If both the differential pressure signal and the CFDS (maintenance phase) signal falsely indicate high altitude:

The vacuum generator will not work on ground
If the CFDS (maintenance phase) signal is not available, the LG signal is used as a backup
The toilets will however work normally at high altitude (cabin differential pressure).

(e) Waste Service Panel Door Switch (WSPDS) 44MG Failure indicates door open DEU B (RH 8) and door closed DEU B (RH 7).

1 On the ground:

a If there is failure in the DEU B or SW or wiring, the system will not operate.

b The VACUUM SYSTEM DISABLED - GROUND SERVICING on the FAP is ON.

2 In Flight:

a The system will however (ignore ground servicing) operate

b In this situation the VACUUM SYSTEM DISABLE message will go off

c They will come on again after the landing.

(f) If the WSPDS 44MG does not operate (indicates door close):

The system will operate on the ground and in the air as normal.

NOTE: If the LLS and the LLT do not operate, the system will not operate and the VACUUM SYSTEM DISABLED-WASTE TANK FULL message on the FAP comes ON.

(5) Fault Handling

(a) All detected system faults during current flight are continuously transmitted to the ARINC 429 data bus and are recorded. On request you can also call up the faults of previous flights (for first and second line maintenance) of the Line Replaceable Units LRU's.
LRU's are:

The toilet assembly (assemblies)
The vacuum generator
The vacuum system controller
The altitude pressure switch
The liquid level sensor.

(b) All Shop Replaceable Units (SRU) defects data are recorded for third line maintenance (shop maintenance). This data is readable through the RS 232-C interface unit.
The SRU are:

The toilet assembly water valve, flush valve and flush control unit
The liquid level transmitter
The vacuum-system controller control-board.

1 Toilet Assembly Faults:

The water valve solenoid
The flush valve motor
The flush valve limit switch (open position)
The flush valve limit switch (closed position)
the flush control unit.

NOTE: The identification letter for toilet location is transmitted together with fault message for fault location.

2 The Vacuum System Controller Fault.

3 The Liquid Level Transmitter Fault.

4 The Altitude Pressure Switch.

5 The Vacuum Generator Overheat.

6 The Liquid Level Sensor Fault.

7 The Aircraft Power Supply 115 V/400 Hz.

8 The Liquid Level Indication FAP,

9 No Data from CFDIU.

(6) Fault Handling

The toilet assembly (assemblies)
The vacuum generator
The vacuum system controller
The altitude pressure switch
The liquid level sensor.

(b) All Shop Replaceable Units (SRU) defects data are recorded for third line maintenance (shop maintenance). This data is readable through the RS 232-C interface unit.
The SRU are:

The toilet assembly water valve, flush valve and flush control unit
The liquid level transmitter
The vacuum-system controller control-board.

1 Toilet Assembly Faults:

The water valve solenoid
The flush valve motor
The flush valve limit switch (open position)
The flush valve limit switch (closed position)
the flush control unit.

NOTE: The identification letter for toilet location is transmitted together with fault message for fault location.

2 The Vacuum System Controller Fault.

3 The Liquid Level Transmitter Fault.

4 The Altitude Pressure Switch.

5 The Vacuum Generator Overheat.

6 The Liquid Level Sensor Fault.

7 The Aircraft Power Supply 115 V/400 Hz.

8 The Liquid Level Indication FAP,

9 No Data from CFDIU.

(d) Transmission Modes

1 No Fault/Fault data is transmitted in two modes:

The normal transmission mode
The menu mode.

The Normal Transmission Mode: In the normal transmission mode the VSC transmits continuously NO FAULT/FAULT data of the vacuum toilet system during flight. The CFDS receives these NO FAULT/FAULT data.
Dependent on what failure the BITE of the VSC detects, the VSC will transmit the text data as follows:

'383141 L A V X, (NOTE)

'383134 V S C'

'383162 L I Q D L V L X M T'

'383169 A L T P R E S S S W'

'383164 V A C U G E N'

'383163 L I Q D L V L S N S R'

'383100 V A C U G E N S U P P L Y'

'383100 L I Q D L V L X M T R /

L I Q D L V L S N S R / V S C'

'313234 'N O C F D I U D A T A.

NOTE: The letter of the defective lavatory will be transmitted together with the text.

Menu Mode: When requested (during line maintenance) the VSC will first transmit the menu as follows:
TOILET SYS
<LAST LEG REPORT>
<PREVIOUS LEGS REPORT>
<LRU IDENTIFICATION>
<TROUBLE SHOOTING DATA>
<CLASS 3 FAULTS>
<RETURN>
If the operator selects an item of the menu, the VSC will transmit the data to the CFDS.

(e) Last Leg Report

The DATE and Universal Time Co-ordinate (UTC) at which each fault occurred
The identity of each faulty LRU, their related SRU, and the ATA chapter reference.

(f) Previous Legs Report

1 The PREVIOUS LEGS REPORT contains:

The aircraft identification
The DATE, UTC and flight leg count at which each fault occured
The identity of each faulty LRU, their related SRU and the ATA chapter reference.

(g) LRU Identification

1 The LRU identification contains the part number of the VSC.

(h) Faults Readable through RS232-C Interface Unit.

1 The SRU function faults of the VSC readable through the RS232-C interface unit for shop maintenance are:

The aircraft power supply 115 V/400 Hz
The analog inputs
The analog outputs
The discrete inputs/outputs
- The flush control unit function
- The indication function
- The liquid level sensor test function
- The motor starting relay function.
The control logic
The ARINC 429 data bus (ARINC Output)
no data from CFDIU (ARINC Input).

(7) Fault Handling

The toilet assembly (assemblies)
The vacuum generator
The vacuum system controller
The altitude pressure switch
The differential pressure transducer
The liquid level sensor.

(b) All Shop Replaceable Units (SRU) defects data are recorded for third line maintenance (shop maintenance). This data is readable through the RS 232-C interface unit.
The SRU are:

The toilet assembly water valve, flush valve and flush control unit
The liquid level transmitter
The vacuum-system controller control-board.

1 Toilet Assembly Faults:

The water valve solenoid
The flush valve motor
The flush valve limit switch (open position)
The flush valve limit switch (closed position)
The flush control unit.

NOTE: The identification letter for toilet location is transmitted together with fault message for fault location.

2 The Vacuum System Controller Fault.

3 The Liquid Level Transmitter Fault.

4 The Vacuum Generator Overheat.

5 The Liquid Level Sensor Fault.

6 The Aircraft Power Supply 115 V/400 Hz.

7 No differential pressure:

A differential pressure below minimum required
A low differential pressure possible leak.

8 The Liquid Level Indication FAP.

9 No Data from CFDIU.

(d) Transmission Modes

1 No Fault/Fault data is transmitted in two modes:

The normal transmission mode
The menu mode.

The Normal Transmission Mode: In the normal transmission mode the DIR transmits continuously NO FAULT/FAULT data of the vacuum toilet system during flight. The CFDS receives these NO FAULT/FAULT data.
Dependent on what failure the BITE of the DIR detects, the DIR will transmit the text data as follows:

'383141 TOILET ASSY L A V X, (NOTE)

'383100 TOILET ASSY LAV X / DEU B

'383113 WASTE SVCE PNL DR SW

'383162 L I Q D L V L X M T R'

'383163 L I Q D L V L S N S R'

'383164 V A C U G E N'

'383100 V A C U G E N S U P P L Y'

'383100 MOTOR START RELAY

'383162 L I Q D L V L X M T R /

L I Q D L V L S N S R'

'383100 L I Q D L V L X M T R

AND L I Q D L V L S N S R'

'383100 LLT AND LLS AND VACU GEN SPLY

'237347 DEU-B

NOTE: The letter of the defective lavatory will be transmitted together with the text.

Menu Mode: When requested (during line maintenance) the DIR will first transmit the menu as follows:
CIDS X - TOILET SYS
<LAST LEG REPORT>
<PREVIOUS LEGS REPORT>
<LRU IDENT>
<TROUBLE SHOOTING DATA>
<CLASS 3 FAULTS>
<GROUND REPORT>
<STATUS>
<RETURN>
If the operator selects an item of the menu, the DIR will transmit the data to the CFDS.

(e) Last Leg Report

The DATE and Universal Time Co-ordinate (UTC) at which each fault occurred
The identity of each faulty LRU, their related SRU, and the ATA chapter reference.

(f) Previous Legs Report

1 The PREVIOUS LEGS REPORT contains:

The aircraft identification
The DATE, UTC and flight leg count at which each fault occurred
The identity of each faulty LRU, their related SRU (on Trouble Shooting Data (STD) page) and the ATA chapter reference.

(g) LRU Identification

(8) Fault Handling

(a) All detected system faults during current flight are continuously transmitted to ARINC 429 data bus and are recorded. You can also get the fault data related to the Line Replaceable Units (LRUs) of the last flights (for the first and second line maintenance).
The LRUs are:

The toilet assembly (assemblies)
The vacuum generator
The liquid level sensor.

(b) Fault data in which the CIDS-DIR transmits through ARINC 429 to the CFDS:

1 The toilet assembly faults:

The water valve solenoid
The flush valve motor
The flush-valve limit switch (open position)
The flush-valve limit switch (closed position)
The flush control unit.

NOTE: The identification letter for toilet location is transmitted together with the fault message and the fault location.

2 The liquid-level transmitter fault

3 The vacuum-generator overheat fault

4 The liquid-level sensor fault

5 Aircraft power supply 115VAC/400Hz

6 No data from the CFDIU.

1 NO FAULT/FAULT data is transmitted in two modes:

The normal transmission mode
The menu mode.

Normal transmission mode: In the normal transmission mode, the DIR continuously transmits the NO FAULT/FAULT data of the vacuum toilet system during the flight. The CFDS receives NO FAULT/FAULT data.
If there is a failure, the BITE of the DIR finds and transmits the text data:

'383141 TOILET ASSY L A V X, (NOTE)

'383100 TOILET ASSY LAV X / DEU B

'383113 WASTE SVCE PNL DR SW

'383162 L I Q D L V L X M T R'

'383163 L I Q D L V L S N S R'

'383164 V A C U G E N'

'383100 V A C U G E N S U P P L Y'

'383100 MOTOR START RELAY

'383162 L I Q D L V L X M T R /

L I Q D L V L S N S R'

'383100 L I Q D L V L X M T R

AND L I Q D L V L S N S R'

'383100 LLT AND LLS AND VACU GEN SPLY

'237347 DEU-B

NOTE: The identification letter for the defective lavatory is transmitted together with the text.

Menu mode: When you select the menu mode (during line maintenance), the DIR will first transmit the menu as follows:
CIDS X - TOILET SYS
<LAST LEG REPORT>
<PREVIOUS LEGS REPORT>
<LRU IDENT>
<TROUBLE SHOOTING DATA>
<CLASS 3 FAULTS>
<GROUND REPORT>
<STATUS>
<RETURN>
If the operator selects an item from the menu, the DIR will transmit the data to the CFDS.

(d) LAST LEG REPORT:

The DATE and Universal Time Coordinated (UTC) at which each fault occurred
Each defective LRU, its related SRU and the ATA chapter reference.

(e) PREVIOUS LEGS REPORT:

The aircraft identification
The DATE, UTC and flight leg count at which each fault occurred
Each defective LRU, its related SRU (on the Trouble Shooting Data (TSD) page) and the ATA chapter reference.

[Rev.10 from 2021] 2026.04.01 05:36:16 UTC