Loss of All Aural and Visual Warnings

TASK 34-48-00-810-809-A
Loss of All Aural and Visual Warnings

1. Possible Causes

GPWC [1WZ]
P/BSW-GPWS/SYS [9WZ]
wiring of the INHIBIT ALL MODE discrete from the GPWC (1WZ) to the GPWS/SYS pushbutton switch (9WZ)

2. Job Set-up Information
A. Referenced Information

3. Fault Confirmation
Subtask 34-48-00-740-066-C

A. Test
(1) Do the BITE test of the Enhanced GPWS AMM 34-48-00-740-002.

4. Fault Isolation
Subtask 34-48-00-810-059-C

A. If the BITE test gives the maintenance message:
GPWS SYS PB SW (9WZ)/GPWC (1WZ):

on the GPWS section of panel 21VU, make sure that the GPWS/SYS pushbutton switch (9WZ) is not pushed (the OFF legend is off)
do a check for ground at pin AB/7D of the GPWC ASM 344801.

(1) If there is no ground:

(2) If there is ground:

(a) If the fault continues:

do a check and repair the wiring of the INHIBIT ALL MODE discrete from the GPWC (1WZ) to the GPWS/SYS pushbutton switch (9WZ) ASM 344801.

Subtask 34-48-00-740-067-A

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:14 UTC