Loss of the Attitude Data on the CAPT PFD with the ATT HDG Selector Switch at CAPT/3

TASK 34-11-00-810-868-A
Loss of the Attitude Data on the CAPT PFD with the ATT HDG Selector Switch at CAPT/3

1. Possible Causes

SEL SW-ATT HDG [13FP]
wiring of the ATT HDG selector switch (13FP)
RELAY-ADIRS 3 28VDC CONTROL [16FP]
DIODE (18FP)
wiring of the ADIRS3 28VDC control relay (16FP)
C/B-NAV PROBES/ADIRU3/PWR/SWTG [8FP]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 34-14-00-810-898-A	Loss of the AC Supply of the ADIRU3
TSM TASK 34-14-00-810-901-A	Loss of the DC Supply of the ADIRU3
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC
ASM 316804
ASM 341101
AMM 34-14-00-740-001	Interface Test of the IR

3. Fault Confirmation
Subtask 34-11-00-710-086-A

A. Test
(1) Not applicable, the fault is evident.

4. Fault Isolation
Subtask 34-11-00-810-189-B

A. If the attitude data go out of view on the CAPT PFD with the ATT HDG selector switch at CAPT/3:

remove the DMC1 and DMC3 AMM 31-63-34-000-001 and AMM 31-63-34-400-001.
do a check for a ground signal at the pin AB/4D of the DMC1 and DMC3.

(1) If there is no ground signal:

replace the SEL SW-ATT HDG [13FP] .

(a) If the fault continues:

do a check and repair the wiring of the ATT HDG selector switch (13FP):
pin A/5 to the ground point
pin A/6 to the first terminal block ASM 316804.

(2) If there is a ground signal:

do the Interface test of the IR (system 3) AMM 34-14-00-740-001.

(a) If the test gives the maintenance message ADIRU3 (1FP3) AC SUPPLY:

do the procedure (Ref. TSM TASK 34-14-00-810-898).

(b) If the test gives the maintenance message ADIRU3 (1FP3) DC SUPPLY:

do the procedure (Ref. TSM TASK 34-14-00-810-901).

replace the RELAY-ADIRS 3 28VDC CONTROL [16FP] .

1 If the fault continues:

replace the DIODE (18FP).

a If the fault continues:
do a check of the wiring of the ADIRS3 28VDC control relay (16FP):
. pin A/4 to the circuit breaker (8FP)
. pin A/X to diode (18FP) pin 2
. pin A/Z to the ground point
. pin A/B to ADIRS3 power shedding relay (14FP) pin A/C1
ASM 341101.

If there is no continuity:
repair the above wirings.

If there is continuity:
do a check of the wiring of the ATT HDG selector switch (13FP):
pin A/1 to diode (18FP) pin 1
pin A/2 to the first terminal block
ASM 341101.
. If there is no continuity:
* repair the above wiring.
. If there is continuity:
* replace the C/B-NAV PROBES/ADIRU3/PWR/SWTG [8FP] .

[Rev.8 from Aug 2018] 2026.04.04 04:40:24 UTC