Loss of the ADR 3 Bus 3 for the SEC 1

TASK 27-94-00-810-846-A
Loss of the ADR 3 Bus 3 for the SEC 1

1. Possible Causes

SEC-1 [1CE1]
wiring of the DGI-07 signal from the SEC 1 (1CE1) to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 34-11-00-810-861-A	Different Angle of Attack Value on the three ADIRUs
TSM TASK 34-13-00-810-998-A	Altitude or Airspeed Discrepancy between CAPT PFD - F/O PFD - STDBY/ISIS
TSM TASK 34-13-00-810-998-B	Altitude or Airspeed Disagree between the CAPT PFD or F/O PFD and Standby Horizon Indicator or ISIS (Aircraft with RVSM capability on the three ADIRUs)
TSM TASK 34-13-81-810-823-A	Runaway or Drift of One ADR1 Parameter Identified by the ELACs and the SECs
ASM 279253
AMM 27-94-34-000-001	Removal of the SEC
AMM 27-94-34-400-001	Installation of the SEC
AMM 27-96-00-740-001	BITE Test of the EFCS (Ground Scanning)

3. Fault Confirmation
Subtask 27-94-00-740-084-A

A. Test
(1) Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.

NOTE: If there is an EFCS message which is not related to an ADR FAULT (NAV ADRX FAULT or ADR-STATUS), do not remove the ADIRU; refer to these procedures:

4. Fault Isolation
Subtask 27-94-00-810-095-B

A. If the BITE test gives the maintenance message:
SEC1 OR BUS3 FROM ADR3

read the Post Flight Report (PFR) for the maintenance messages ADR1 with AFS in IDENT or ADIRU 1/2/3 DISAGREE with the AFS source.

(1) If one of these maintenance messages comes into view on the PFR:

do this trouble shooting procedure: (Ref. TSM TASK 34-13-81-810-823).

(2) If these maintenance messages do not come into view on the PFR:

replace the SEC-1 [1CE1] AMM 27-94-34-000-001 and AMM 27-94-34-400-001.

(a) If the fault continues:

do a check and repair the wiring of the DGI-07 signal from the SEC 1 (1CE1) to the first terminal block, COM and MON parts ASM 279253.

Subtask 27-94-00-740-085-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:28:15 UTC