Different Total Pressure on the ADIRU 2 and the ADIRU 3

TASK 34-11-00-810-841-A
Different Total Pressure on the ADIRU 2 and the ADIRU 3

1. Possible Causes

PROBE-PITOT, 2 [9DA2]
PROBE-PITOT, 3 [9DA3]
ADM-R TOTAL PRESSURE [19FP2]
ADM-STBY TOTAL PRESSURE [19FP3]

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ARINC READER

B. Referenced Information

REFERENCE	DESIGNATION
AMM 30-31-00-720-001	Functional Check of the Insulation Resistance of the Pitot Probe Heater
AMM 34-10-00-170-001	Flushing of the Principal Total Pressure Lines
AMM 34-10-00-170-003	Draining and Flushing of Standby Pneumatic Circuits
AMM 34-10-00-860-002	ADIRS Start Procedure
AMM 34-11-15-000-001	Removal of the Pitot Probe
AMM 34-11-15-400-001	Installation of the Pitot Probe
AMM 34-11-17-000-001	Removal of the Air Data Module
AMM 34-11-17-400-001	Installation of the Air Data Module
AMM 34-13-00-790-002	Leak Test of the Principal Static and Total Air Data System
ASM 341301
AMM 34-21-00-790-001	Low-Range Leak Test of the Standby Pneumatic Circuits
AMM 34-22-25-170-001	Draining and Flushing of the Standby Static and Standby Total Pressure lines (ISIS)
AMM 34-22-25-790-001	Low range Leak Test of the Standby Pneumatic circuits

3. Fault Confirmation
Subtask 34-11-00-710-057-A

A. Test
Not applicable, you cannot confirm this fault on the ground.

4. Fault Isolation
Subtask 34-11-00-810-098-B ** ON A/C NOT FOR ALL

A. If the POST FLIGHT REPORT gives the maintenance message ADM2 (19FP2)/ ADM3 (19FP3):

do a visual check of the PROBE-PITOT, 2 [9DA2] and PROBE-PITOT, 3 [9DA3] .

(1) If the pitot probe 2 (9DA2) or the pitot probe 3 (9DA3) is damaged:

replace the defective pitot probe AMM 34-11-15-000-001 and AMM 34-11-15-400-001.

(2) If the pitot probes are not damaged:

do the ADIRS start procedure AMM 34-10-00-860-002
connect the ARINC READER to the test connector 198VC on the panel 188VU and to the test connector 199VC on the panel 187VU ASM 341301

compare the total pressure read on these labels:

ADIRU 1 199VC ! 19FP1 LABEL 242

pins GG, HH !

ADIRU 2 198VC ! 19FP2 LABEL 242

pins GG, HH !

ADIRU 3 199VC ! 19FP3 LABEL 242

pins y, z !

(a) If the value of the total pressure (ADM 2 or ADM 3) is different:

replace the defective total pressure ADM AMM 34-11-17-000-001 and AMM 34-11-17-400-001.

(b) If the values are the same:

do the flushing of the total pressure line of the air data module (ADM 2) AMM 34-10-00-170-001
do the draining and flushing of the standby static and standby total pressure line of the air data module AMM 34-10-00-170-003
do the leak test of the main air data system (CAPT and F/O) AMM 34-13-00-790-002.
do the low range leak test of the standby pneumatic circuit AMM 34-21-00-790-001.

(3) Do the functional test of the pitot-probe-heater insulation resistance AMM 30-31-00-720-001.

if the resistance value is not in the correct range, replace the defective pitot probe (9DA2 or 9DA3) AMM 34-11-15-000-001 and AMM 34-11-15-400-001.

Subtask 34-11-00-810-098-D ** ON A/C NOT FOR ALL

A. If the POST FLIGHT REPORT gives the maintenance message ADM2 (19FP2)/ ADM3 (19FP3):

do a visual check of the PROBE-PITOT, 2 [9DA2] and PROBE-PITOT, 3 [9DA3] .

(1) If the pitot probe 2 (9DA2) or the pitot probe 3 (9DA3) is damaged:

replace the defective pitot probe AMM 34-11-15-000-001 and AMM 34-11-15-400-001.

(2) If the pitot probes are not damaged:

do the ADIRS start procedure AMM 34-10-00-860-002
connect the ARINC READER to the test connector 198VC on the panel 188VU and to the test connector 199VC on the panel 187VU ASM 341301

compare the total pressure read on these labels:

ADIRU 1 199VC ! 19FP1 LABEL 242

pins GG, HH !

ADIRU 2 198VC ! 19FP2 LABEL 242

pins GG, HH !

ADIRU 3 199VC ! 19FP3 LABEL 242

pins y, z !

(a) If the value of the total pressure (ADM 2 or ADM 3) is different:

replace the defective total pressure ADM AMM 34-11-17-000-001 and AMM 34-11-17-400-001.

(b) If the values are the same:

do the flushing of the total pressure line of the air data module (ADM 2) AMM 34-10-00-170-001
do the draining and flushing of the standby static and standby total pressure line of the air data module AMM 34-22-25-170-001
do the leak test of the main air data system (CAPT and F/O) AMM 34-13-00-790-002.
do the leak test of the standby pneumatic circuit AMM 34-22-25-790-001.

(3) Do the functional test of the pitot-probe-heater insulation resistance AMM 30-31-00-720-001.

if the resistance value is not in the correct range, replace the defective pitot probe (9DA2 or 9DA3) AMM 34-11-15-000-001 and AMM 34-11-15-400-001.

Subtask 34-11-00-810-099-A

B. After the subsequent flight, if the fault continues:

replace the ADM-R TOTAL PRESSURE [19FP2] AMM 34-11-17-000-001 and AMM 34-11-17-400-001.

Subtask 34-11-00-810-100-A

C. After the subsequent flight, if the fault continues:

replace the ADM-STBY TOTAL PRESSURE [19FP3] AMM 34-11-17-000-001 and AMM 34-11-17-400-001.

[Rev.8 from Aug 2018] 2026.04.04 04:32:15 UTC