Loss of the Aural Warnings

TASK 34-48-00-810-813-A
Loss of the Aural Warnings

1. Possible Causes

LOUD SPEAKER-CAPT [7WW]
wiring of the ALARM 2 INPUT bus from the CAPT loud speaker (7WW) to the first terminal block
LOUD SPEAKER-F/O [8WW]
wiring of the ALARM 2 INPUT bus from the F/O loud speaker (8WW) to the first terminal block
GPWC [1WZ]
wiring of the AUDIO OUTPUT bus from the GPWC (1WZ) to the first terminal block

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-53-21-000-001	Removal of the Loudspeakers
AMM 31-53-21-400-001	Installation of the Loudspeakers
AMM 34-48-00-710-001	Operational Test of GPWS Ground Self-test Function
ASM 344801
AMM 34-48-34-000-001	Removal of the GPWC
AMM 34-48-34-400-001	Installation of the GPWC

3. Fault Confirmation
Subtask 34-48-00-710-050-B

A. Test
(1) Do operational test of Enhanced GPWS ground self-test function AMM 34-48-00-710-001.

4. Fault Isolation
Subtask 34-48-00-810-063-A

A. If there is no audio signal at the CAPT loud speaker only:

(1) If the fault continues:

do a check and repair the wiring of the ALARM 2 INPUT bus from the CAPT loud speaker (7WW) to the first terminal block ASM 344801.

Subtask 34-48-00-810-064-A

B. If there is no audio signal at the F/O loud speaker only:

(1) If the fault continues:

do a check and repair the wiring of the ALARM 2 INPUT bus from the F/O loud speaker (8WW) to the first terminal block ASM 344801.

Subtask 34-48-00-810-065-A

C. If there is no audio signal at the two loud speakers:

(1) If the fault continues:

do a check and repair the wiring of the AUDIO OUTPUT bus from the GPWC (1WZ) to the first terminal block ASM 344801.

Subtask 34-48-00-710-051-A

D. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:15 UTC