Failure of the HPTCC Valve Channel A on Engine 1

TASK 75-21-00-810-803-A
Failure of the HPTCC Valve Channel A on Engine 1

1. Possible Causes

TCC sensor(s)
High Pressure Turbine Active Clearance Control (HPTACC) Valve
HMU-1 [4000KC1]
ECU [4000KS]
harness J7
harness HJ7

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 73-21-10-000-001	Removal of the Hydromechanical Unit (HMU)
AMM 73-21-10-000-002	Removal of the Hydromechanical Unit (HMU)
AMM 73-21-10-400-001	Installation of the Hydromechanical Unit (HMU)
AMM 73-21-10-400-002	Installation of the Hydromechanical Unit (HMU)
AMM 73-21-50-000-006	Removal of J7 Harness
AMM 73-21-50-000-040	Removal of the HJ7 Harness for SAC Engines
AMM 73-21-50-210-001	Visual Inspection of the Wiring Harness
AMM 73-21-50-210-002	Visual Inspection of the Wiring Harnesses
AMM 73-21-50-400-006	Installation of the J7 Harness
AMM 73-21-50-400-040	Installation of the HJ7 Harness for SAC Engines
AMM 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
AMM 73-21-70-000-001	Removal of the High Pressure Turbine Clearance Control (HPTCC) Sensor
AMM 73-21-70-000-002	Removal of the High Pressure Turbine Clearance Control (HPTCC) Sensor
AMM 73-21-70-400-001	Installation of the High Pressure Turbine Clearance Control (HPTCC) Sensor
AMM 73-21-70-400-002	Installation of the High Pressure Turbine Clearance Control (HPTCC) Sensor
AMM 73-29-00-710-040	Operational Test of the FADEC on the ground (with Engine Motoring)
AMM 75-21-10-000-001	Removal of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
AMM 75-21-10-000-002	Removal of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
AMM 75-21-10-400-001	Installation of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
AMM 75-21-10-400-002	Installation of the High Pressure Turbine Active Clearance Control (HPTACC) Valve

3. Fault Confirmation
Subtask 75-21-00-710-054-D ** ON A/C NOT FOR ALL

A. Do the operational test of the FADEC 1A on the ground (with engine motoring) AMM 73-29-00-710-040.

Subtask 75-21-00-710-054-E ** ON A/C NOT FOR ALL

A. Do the operational test of the FADEC 1A on the ground (with engine motoring) AMM 73-29-00-710-040.

4. Fault Isolation
Subtask 75-21-00-810-054-E ** ON A/C NOT FOR ALL

A. The failure message is triggered if there is a difference between the actual position and the feedback position of the valve of more than 5% and the fault continues for more than 7 seconds.
(1) If the failure message HPTC VLV (POS), HMU on channel 1A is not confirmed:
(a) No maintenance action required.
(2) If the failure message HPTC VLV (POS), HMU on channel 1A is not confirmed but is repetitive:
(a) Do the following trouble shooting at next maintenance opportunity:
1 Do a check of the Post Flight Report (PFR) and the Schedule Maintenance Report (SMR)/Class 3 report for TCC SNSR, J13, ECU.
If the failure message is present:

disconnect the TCC sensor(s).

NOTE: Engines post SB 73-129 are equipped with only one sensor.

Do a cleaning of the harness connectors and receptacles using a bristle brush with stoddart solvent (CP 2011) AMM 73-21-50-210-001.
reconnect the connectors to the TCC sensor(s).

NOTE: Tighten the connector by hand plus one eighth of a turn. If necessary use soft nose pliers.

a If the fault continues:

replace the TCC sensor(s) AMM 73-21-70-000-001 and AMM 73-21-70-400-001.

NOTE: Engines post SB 73-129 are equipped with only one sensor.

2 If the fault continues:

replace the High Pressure Turbine Active Clearance Control (HPTACC) Valve AMM 75-21-10-000-001 and AMM 75-21-10-400-001.

3 If the fault continues:

replace the HMU-1 [4000KC1] AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

4 If the fault continues:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

5 If the fault continues:

replace the harness J7 AMM 73-21-50-000-006 and AMM 73-21-50-400-006.

(3) If the failure message HPTC VLV (POS), HMU on channel 1A is confirmed:
(a) Disconnect the harness J7 from the ECU and do a check of resistance between:
. pins 23 and 24 (17 to 23 Ohms).
1 If the resistance values are in the specified limits:

replace the High Pressure Turbine Active Clearance Control (HPTACC) Valve AMM 75-21-10-000-001 and AMM 75-21-10-400-001.

a If the fault continues:

replace the HMU-1 [4000KC1] AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

b If the fault continues:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

c If the fault continues:

replace the harness J7 AMM 73-21-50-000-006 and AMM 73-21-50-400-006.

(b) If the resistance values are out of the specified limits:

disconnect the harness J7 from the HMU and do a check of the HMU resistance between:
. pins 23 and 24 (17 to 23 Ohms).

1 If the resistance values are in the specified limits:

replace the harness J7 AMM 73-21-50-000-006 and AMM 73-21-50-400-006.

2 If the resistance values are out of the specified limits:

replace the HMU-1 [4000KC1] AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

NOTE: Tighten the connector by hand plus one eighth of a turn. If necessary use soft nose pliers.

Subtask 75-21-00-810-054-F ** ON A/C NOT FOR ALL

A. The failure message is triggered if there is a difference between the actual position and the feedback position of the valve of more than 5% and the fault continues for more than 7 seconds.
(1) If the failure message HPTC VLV (POS), HMU on channel 1A is not confirmed:
(a) No maintenance action required.
(2) If the failure message HPTC VLV (POS), HMU on channel 1A is not confirmed but is repetitive:
(a) Do the following trouble shooting at next maintenance opportunity:

PRE SB 73-0268

1 Do a check of the Post Flight Report (PFR) and the Schedule Maintenance Report (SMR)/Class 3 report for TCC SNSR, J13, ECU.
If the failure message is present:

disconnect the TCC sensor(s).

NOTE: Engines post SB 73-046 are equipped with only one sensor.

Do a cleaning of the harness connectors and receptacles using a bristle brush with stoddart solvent (CP 2011) AMM 73-21-50-210-002.
reconnect the connectors to the TCC sensor(s).

NOTE: Tighten the connector by hand plus one eighth of a turn. If necessary use soft nose pliers.

a If the fault continues:

replace the TCC sensor(s) AMM 73-21-70-000-002 and AMM 73-21-70-400-002.

NOTE: Engines post SB 73-046 are equipped with only one sensor.

2 If the fault continues:

END OF PRE SB 73-0268

replace the High Pressure Turbine Active Clearance Control (HPTACC) Valve AMM 75-21-10-000-002 and AMM 75-21-10-400-002.

3 If the fault continues:

replace the HMU-1 [4000KC1] AMM 73-21-10-000-002 and AMM 73-21-10-400-002.

4 If the fault continues:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

5 If the fault continues:

replace the harness HJ7 AMM 73-21-50-000-040 and AMM 73-21-50-400-040.

(3) If the failure message HPTC VLV (POS), HMU on channel 1A is confirmed:
(a) Disconnect the harness HJ7 from the ECU and do a check of resistance between:
. pins 23 and 24 (17 to 23 Ohms).
1 If the resistance values are in the specified limits:

replace the High Pressure Turbine Active Clearance Control (HPTACC) Valve AMM 75-21-10-000-002 and AMM 75-21-10-400-002.

a If the fault continues:

replace the HMU-1 [4000KC1] AMM 73-21-10-000-002 and AMM 73-21-10-400-002.

b If the fault continues:

replace the ECU [4000KS] AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

c If the fault continues:

replace the harness HJ7 AMM 73-21-50-000-040 and AMM 73-21-50-400-040.

(b) If the resistance values are out of the specified limits:

disconnect the harness HJ7 from the HMU and do a check of the HMU resistance between:
. pins 23 and 24 (17 to 23 Ohms).

1 If the resistance values are in the specified limits:

replace the harness HJ7 AMM 73-21-50-000-040 and AMM 73-21-50-400-040.

2 If the resistance values are out of the specified limits:

replace the HMU-1 [4000KC1] AMM 73-21-10-000-002 and AMM 73-21-10-400-002.

NOTE: Tighten the connector by hand plus one eighth of a turn. If necessary use soft nose pliers.

Subtask 75-21-00-710-055-D ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.
(1) No additional maintenance action is required if the fault is not confirmed.
(2) Continue the fault isolation procedure if the fault continues.

[Rev.8 from Aug 2018] 2026.04.04 04:37:01 UTC