Failure of AFT Waste-Water Ice-Protection System

TASK 30-71-00-810-806-A
Failure of AFT Waste-Water Ice-Protection System

1. Possible Causes

CONTROL UNIT, WASTE WATER ICE PROTECTION- [15DU]
DRAINMAST "F" [14DU]
wiring
CONTROL UNIT (103DW)
SENSOR-TEMP, WASTE WTR [60DU]
HEATER 61DU
HEATER 62DU
microfuse
CONTROL UNIT 35DU
SENSOR-TEMP, WASTE WTR [70DU]
HEATER 71DU
HEATER 72DU
HEATER 73DU

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	SPRAY - COOLING

B. Referenced Information

REFERENCE	DESIGNATION
AMM 30-71-00-710-002	Operational Test of the Waste-Water Ice-Protection Heater-Elements
AMM 30-71-00-740-001	BITE Test of the Drainmast Ice Protection (through CIDS SYSTEM/TEST)
ASM 307101
AMM 30-71-17-000-001	Removal of the Waste-Water De-icing Sensor
AMM 30-71-17-400-001	Installation of the Waste-Water De-icing Sensor
AMM 30-71-18-000-001	Removal of Sensor
AMM 30-71-18-400-001	Installation of Sensor
AMM 30-71-19-000-001	Removal of Sensor
AMM 30-71-19-400-001	Installation of Sensor
AMM 30-71-34-000-001	Removal of the Waste-Water Ice-Protection Control-Unit
AMM 30-71-34-400-001	Installation of the Waste-Water Ice-Protection Control-Unit
AMM 30-71-51-000-001	Removal of the Drain Mast
AMM 30-71-51-400-001	Installation of the Drain Mast
AMM 30-71-53-000-001	Removal of the Waste-Water De-icing Heater Elements
AMM 30-71-53-400-001	Installation of the Waste-Water De-icing Heater Elements
AMM 30-71-57-000-001	Removal of the AFT Drain-Mast Pipe Heater-Elements
AMM 30-71-57-400-001	Installation of the AFT Drain-Mast Pipe Heater-Elements
AMM 30-71-58-000-001	Removal of AFT Waste-Pipe Heating Elements
AMM 30-71-58-400-001	Installation of AFT Waste-Pipe Heating Elements
AMM 30-73-00-740-001	BITE Test of the Potable Water Ice-Protection
AMM 30-73-34-000-001	Removal of the Potable and Waste Water Ice Protection Control Unit
AMM 30-73-34-400-001	Installation of the Potable and Waste Water Ice Protection Control Unit

3. Fault Confirmation
Subtask 30-71-00-710-060-A ** ON A/C NOT FOR ALL

A. Do the operational test of the waste-water ice-protection system AMM 30-71-00-710-002.

Subtask 30-71-00-710-060-B ** ON A/C NOT FOR ALL

A. Do the BITE Test of the Drainmast Ice Protection (via CIDS System/Test) AMM 30-71-00-740-001.

4. Fault Isolation
Subtask 30-71-00-810-059-A

A. If the green 'UNIT' LED of the CONTROL UNIT 15DU does not come on:
Replace the CONTROL UNIT, WASTE WATER ICE PROTECTION- [15DU] AMM 30-71-34-000-001 and AMM 30-71-34-400-001.

Subtask 30-71-00-810-060-A

B. If the green 'HTR' LED of the CONTROL UNIT 15DU does not come on:
Do a check of the resistance value of the drainmast heater and temperature sensor. Refer to the related CMM for the correct values.
(1) If the fault continues:
Replace the DRAINMAST "F" [14DU] AMM 30-71-51-000-001 and AMM 30-71-51-400-001.
(a) If the fault continues:
Do a check and repair the wiring between:

CONTROL UNIT 15DU connector A/4 and DRAINMAST 14DU connector A/D
CONTROL UNIT 15DU connector A/5 and DRAINMAST 14DU connector A/E
CONTROL UNIT 15DU connector A/8 and DRAINMAST 14DU connector A/B
DRAINMAST 14DU connector A/C and GND
DRAINMAST 14DU connector A/A and GND ASM 307101.

Subtask 30-71-00-810-061-A

C. If the green 'UNIT' LED and the green 'HTR' LED of the CONTROL UNIT 15DU do not come on:
Do a check for the subsequent signals:

115VAC at CONTROL UNIT 15DU connector A/14,
GND at CONTROL UNIT 15DU connector A/15 ASM 307101.

(1) If the two signals are OK:
Replace the CONTROL UNIT, WASTE WATER ICE PROTECTION- [15DU] AMM 30-71-34-000-001 and AMM 30-71-34-400-001.
(2) If there is no 115 VAC:
Do a check and repair the wiring between CONTROL UNIT 15DU connector A/14 and CB 11DU ASM 307101.
(3) If there is no GND:
Do a check and repair the wiring between CONTROL UNIT 15DU connector A/15 and GND ASM 307101.

Subtask 30-71-00-810-075-C ** ON A/C NOT FOR ALL

D. If the green 'UNIT' LED and the green 'HTR' LED of the CONTROL UNIT 5DU come on:

do the BITE test of the potable-water ice-protection system AMM 30-73-00-740-001.

(1) If the green I/II LED of the CONTROL UNIT 103DW does not come on:

do a check of the related microfuses.

(a) If the microfuses are OK:

replace the CONTROL UNIT (103DW) AMM 30-73-34-000-001 and AMM 30-73-34-400-001.

(b) If the fault continues:

NOTE: Remove the insulation from around the SENSOR 60DU, the HEATER 61DU and the HEATER 62DU.

apply SPRAY - COOLING to the SENSOR 60DU for at least 10 s,
stop for approx. 120 s,
do a check of the temperature of the HEATER 61DU and HEATER 62DU.

1 If the HEATER 61DU and HEATER 62DU stay cold:

replace the SENSOR-TEMP, WASTE WTR [60DU] AMM 30-71-17-000-001 and AMM 30-71-17-400-001.

2 If the HEATER 61DU stays cold:

replace the HEATER 61DU AMM 30-71-53-000-001 and AMM 30-71-53-400-001.

3 If the HEATER 62DU stays cold:

replace the HEATER 62DU AMM 30-71-53-000-001 and AMM 30-71-53-400-001.

do a check for a short circuit ASM 307101,
replace the microfuse .

Subtask 30-71-00-810-075-D ** ON A/C NOT FOR ALL

D. Fault of the CONTROL UNIT 35DU
(1) If the green I/II LED of the CONTROL UNIT 35DU does not come on:
Do a check of the related microfuses.
(a) If the microfuses are serviceable:
Replace the CONTROL UNIT 35DU AMM 30-71-34-000-001 and AMM 30-71-34-400-001.
(b) If the fault continues:
1 Remove the insulation from around the SENSOR 60DU and the HEATERS 61DU and 62DU.
2 Apply SPRAY - COOLING to the SENSOR 60DU for at least 10 s.
3 Stop for approx. 120 s.
4 Do a check of the temperature of the HEATERS 61DU and 62DU.
a If the HEATERS 61DU and 62DU stay cold:
Replace the SENSOR-TEMP, WASTE WTR [60DU] AMM 30-71-19-000-001 and AMM 30-71-19-400-001.
b If the HEATER 61DU stays cold:
Replace the HEATER 61DU AMM 30-71-57-000-001 and AMM 30-71-57-400-001.
c If the HEATER 62DU stays cold:
Replace the HEATER 62DU AMM 30-71-57-000-001 and AMM 30-71-57-400-001.
(c) If one microfuse is not serviceable:
1 Do a check for a short circuit ASM 307101.
2 Replace the microfuse .
(2) If the green III/IV LED of the CONTROL UNIT 35DU does not come on:
Do a check of the related microfuses.
(a) If the microfuses are serviceable:
Replace the CONTROL UNIT 35DU AMM 30-71-34-000-001 and AMM 30-71-34-400-001.
(b) If the fault continues:
1 Remove the insulation from around the SENSOR 70DU and the HEATERs 71DU, 72DU and 73DU.
2 Apply SPRAY - COOLING to the SENSOR 70DU for at least 10 s.
3 Stop for approx. 120 s.
4 Do a check of the HEATERS 71DU, 72DU and 73DU.
a If the HEATERs 71DU, 72DU and 73DU stay cold:
Replace the SENSOR-TEMP, WASTE WTR [70DU] AMM 30-71-18-000-001 and AMM 30-71-18-400-001.
b If the HEATER 71DU stays cold:
Replace the HEATER 71DU AMM 30-71-58-000-001 and AMM 30-71-58-400-001.
c If the HEATER 72DU stays cold:
Replace the HEATER 72DU AMM 30-71-58-000-001 and AMM 30-71-58-400-001.
d If the HEATER 73DU stays cold:
Replace the HEATER 73DU AMM 30-71-58-000-001 and AMM 30-71-58-400-001.
(c) If one microfuse is not serviceable:
1 Do a check for a short circuit ASM 307101.
2 Replace the microfuse .

Subtask 30-71-00-710-061-A

E. Do the test as given in Para. 3.A.

5. Close-up
Subtask 30-71-00-860-055-A

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:29:46 UTC