Failure of the LPTC Valve on Engine 1

TASK 75-22-00-810-805-A
Failure of the LPTC Valve on Engine 1

1. Possible Causes

LPTC valve
HMU
ECU [4000KS]

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 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
AMM 73-29-00-710-040	Operational Test of the FADEC on the ground (with Engine Motoring)
AMM 75-22-10-000-001	Removal of the Low Pressure Turbine Active Clearance Control Valve (LPTACC).
AMM 75-22-10-000-002	Removal of the Low Pressure Turbine Active Clearance Control (LPTACC) Valve
AMM 75-22-10-400-001	Installation of the Low Pressure Turbine Active Clearance Control Valve (LPTACC).
AMM 75-22-10-400-002	Installation of the Low Pressure Turbine Active Clearance Control (LPTACC) Valve

3. Fault Confirmation
Subtask 75-22-00-710-058-A ** 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 75-22-00-810-054-A ** ON A/C NOT FOR ALL

A. This fault is generated if the actual valve position disagrees with the demanded valve position for a set time interval.
(1) If the failure message LPTC VLV, HMU is not confirmed:
(a) No maintenance action is required.
(2) If the failure message LPTC VLV, HMU is not confirmed but is repetitive:

NOTE: No maintenance action is required unless the fault becomes too repetitive.

- do the following steps until the fault is corrected.
(a) Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
(b) If the fault continues during the subsequent flights:

replace the HMU AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

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

(3) If the failure message LPTC VLV, HMU is confirmed:
(a) Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
(b) If the fault continues:

replace the HMU AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

Subtask 75-22-00-810-054-B ** ON A/C NOT FOR ALL

A. This fault is generated if the actual valve position disagrees with the demanded valve position for a set time interval.
(1) If the failure message LPTC VLV (POS), HMU is not confirmed:
(a) No maintenance action is required.
(2) If the failure message LPTC VLV (POS), HMU is not confirmed but is repetitive:

NOTE: No maintenance action is required unless the fault becomes too repetitive.

- do the following steps until the fault is corrected.
(a) Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
(b) If the fault continues during the subsequent flights:

replace the HMU AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

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

(3) If the failure message LPTC VLV (POS), HMU is confirmed:
(a) Replace the LPTC valve AMM 75-22-10-000-001 and AMM 75-22-10-400-001.
(b) If the fault continues:

replace the HMU AMM 73-21-10-000-001 and AMM 73-21-10-400-001.

replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

Subtask 75-22-00-810-054-C ** ON A/C NOT FOR ALL

NOTE: No maintenance action is required unless the fault becomes too repetitive.

- do the following steps until the fault is corrected.
(a) Replace the LPTC valve AMM 75-22-10-000-002 and AMM 75-22-10-400-002.
(b) If the fault continues during the subsequent flights:

replace the HMU AMM 73-21-10-000-002 and AMM 73-21-10-400-002.

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

(3) If the failure message LPTC VLV (POS), HMU is confirmed:
(a) Replace the LPTC valve AMM 75-22-10-000-002 and AMM 75-22-10-400-002.
(b) If the fault continues:

replace the HMU AMM 73-21-10-000-002 and AMM 73-21-10-400-002.

replace the ECU (4000KS) AMM 73-21-60-000-001 and AMM 73-21-60-400-001.

Subtask 75-22-00-710-059-A ** ON A/C NOT FOR ALL

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

[Rev.8 from Aug 2018] 2026.04.04 04:37:03 UTC