(6)
(WDM 34-21-22)

E.  Initial Evaluation
(1)  
For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

(2)  
If the maintenance message does not show on the CDU and the status code does not show on the ISDU, then there was an intermittent fault.

(3)  
If the maintenance message shows on the CDU and the status code shows on the ISDU, then do the Fault Isolation Procedure below.

F. Fault Isolation Procedure
(1)
Replace the TAT probe.
These are the tasks:
Total Air Temperature Probe Removal, AMM TASK 34-21-06-000-801,
Total Air Temperature Probe Installation, AMM TASK 34-21-06-400-801.

(a)  
For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

(b)  
If the maintenance message does not show on the CDU and the status code does not show on the ISDU, then you corrected the fault.

(c)  
If the maintenance message shows on the CDU and the status code shows on the ISDU, then continue.

(2)  
Do this check of the wiring between the applicable ADIRU and the TAT probe:

(a)  
Remove the ADIRU. To remove it, do this task: Air Data Inertial Reference Unit Removal, AMM TASK 34-21-01-000-801.

(b)  
Remove the TAT probe. To remove it, do this task: Total Air Temperature Probe Removal, AMM TASK 34-21-06-000-801.

(c)
For the left ADIRU, do a wiring check between these pins of connector D277 for the TAT probe and connector D3687A for the ADIRU:

(d)  
For the right ADIRU, do a wiring check between these pins of connector D277 for the TAT probe and connector D3693A for the ADIRU:

EFFECTIVITY SIL ALL  34-21 TASK 813 
D633A103-SIL BOEING PROPRIETARY -Copyright # Unpublished Work -See title page for details  Page 225 Oct 15/2008 

D277  D3687A 
pin 3  ------------------- pin H8 
pin 4  ------------------- pin J8 

D277  D3693A
pin5 -------------------pinH8 pin2 -------------------pinJ8

(e)  If you find a problem with the wiring, then do these steps: 1) Repair the wiring. 2) Re-install the ADIRU. To install it, do this task: Air Data Inertial Reference Unit
Installation, AMM TASK 34-21-01-400-801. 3) Re-install the TAT probe. To install it, do this task: Total Air Temperature Probe
Installation, AMM TASK 34-21-06-400-801.
4)  For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

5)  If the maintenance message does not show on the CDU and the status code does not
show on the ISDU, then you corrected the fault.
(f)  If you do not find a problem with the wiring, then do this step and continue:
1)  Re-install the TAT probe. To install it, do this task: Total Air Temperature Probe Installation, AMM TASK 34-21-06-400-801.
(3)  Install a new ADIRU. To install it, do this task: Air Data Inertial Reference Unit Installation, AMM TASK 34-21-01-400-801.
(a)  
For
the
applicable
ADIRS,
do
this
task:
ADIRS
BITE
Procedure,
34-21
TASK
801.

(b)  
If the maintenance message does not show on the CDU and the status code does not show on the ISDU, then you corrected the fault.

-------------------------END OF TASK ---------------------------
814.  AOA Signal Fail -Fault Isolation
　
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