Flight Ground Status Invalid Fault on EIU-1

TASK 73-25-00-810-B29-A
Flight Ground Status Invalid Fault on EIU-1

1. Possible Causes

wiring
LGCIU-1 [5GA1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 32-31-71-000-001	Removal of the LGCIU
AMM 32-31-71-400-001	Installation of the LGCIU
AWM 732507
AMM 73-25-34-000-802	Removal of the Engine Interface Unit (EIU)
AMM 73-25-34-400-802	Installation of the Engine Interface Unit (EIU)

3. Fault Confirmation
Subtask 73-25-00-710-568-A ** ON A/C NOT FOR ALL

A. Not Applicable

4. Fault Isolation
Subtask 73-25-00-810-452-A ** ON A/C NOT FOR ALL

A. If no fault regarding the BUS bar is reported or if fault continues:
(1) Remove the EIU-1 (1KS1) AMM 73-25-34-000-802.
(2) Remove the LGCIU-1 (5GA1) AMM 32-31-71-000-001.
(3) Test the circuits AWM 732507. Refer to Table 1. Look for:
(a) Wire-to-wire shorts
(b) Shorts to ground
(c) Continuity (less than 5 ohms resistance).

NOTE: A short to ground is found when the resistance is less than 100 000 (100K) ohms.

Table 1: 28 VDC Circuit Connector Contacts

LGCIU-1 (5GA1) Contacts	EIU-1 (1KS1) Connector AA Contacts
3G	5D
3K	5E

(4) If a problem is found:
(a) Repair or replace wiring AWM 732507.
(b) Install the EIU-1 (1KS1) AMM 73-25-34-400-802.
(c) Install the LGCIU-1 (5GA1) AMM 32-31-71-400-001.
(5) If no problem is found:
(a) Replace LGCIU-1 [5GA1] AMM 32-31-71-400-001.
(b) Install the EIU-1 (1KS1) AMM 73-25-34-400-802.
(6) Do a subsequent flight to confirm the fault is fixed.
(7) If the fault continues on next Post Flight Report (PFR):
(a) Replace LGCIU-1 [5GA1] AMM 32-31-71-000-001 and AMM 32-31-71-400-001.

5. Close-up
Subtask 73-25-00-860-174-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.

[Rev.8 from Aug 2018] 2026.04.04 04:36:50 UTC