N1 Actual Lower than N1 Command on Engine 1 or 2

TASK 77-00-00-810-833-A
N1 Actual Lower than N1 Command on Engine 1 or 2

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC
AMM 72-00-00-200-026	Inspection/Check of the PS3 Line
AMM 72-00-00-200-029	Inspection/Check of the PS3 Line
AMM 72-00-00-220-001	Inspection of the PS3 Line Connections
AMM 72-00-00-280-001	Dry out and Cleaning of the PS3 Line
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)

3. Fault Confirmation
Subtask 77-00-00-710-107-A ** ON A/C NOT FOR ALL

A. Test
(1) Make sure that the same crew observation is applicable with the DMC3 switched on on panel 8VU.

4. Fault Isolation
Subtask 77-00-00-810-088-A ** ON A/C NOT FOR ALL

A. If the same crew observation is not applicable when the DMC3 is switched on:
(1) Replace the DMC-1 [1WT1] AMM 31-63-34-000-001 and AMM 31-63-34-400-001.

Subtask 77-00-00-810-089-A ** ON A/C NOT FOR ALL

B. If the same crew observation is applicable when the DMC3 is switched on:
(1) Do a check of the PS3 line AMM 72-00-00-200-029 and AMM 72-00-00-280-001 and AMM 72-00-00-220-001.

(2) If no damage is found:

Subtask 77-00-00-810-089-B ** ON A/C NOT FOR ALL

B. If the same crew observation is applicable when the DMC3 is switched on:
(1) Do a check of the PS3 line AMM 72-00-00-200-026.

(2) If no damage is found:

Subtask 77-00-00-710-108-A ** ON A/C NOT FOR ALL

C. After the subsequent flight, make sure that the fault does not continue.

[Rev.8 from Aug 2018] 2026.04.04 04:37:31 UTC