Failure of the L Static Probe (PHC 3)

TASK 30-31-00-810-827-A
Failure of the L Static Probe (PHC 3)

1. Possible Causes

PROBE-L STATIC, 3 [7DA3]
PHC-3 [6DA3]
wiring from the PHC 3 (6DA3) to the L static probe 3 (7DA3)
wiring
ADIRU-3 [1FP3]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 30-31-00-710-001	Operational Test of the Probe Ice Protection
ASM 303103
AMM 30-31-34-000-002	Removal of the Probe Heat Computer (PHC)
AMM 30-31-34-400-002	Installation of the Probe Heat Computer (PHC)
AMM 34-11-16-000-001	Removal of the Static Probe
AMM 34-11-16-400-002	Installation of the Static Probe
AMM 34-12-34-000-001	Removal of the ADIRU
AMM 34-12-34-400-001	Installation of the ADIRU
ASM 341302

3. Fault Confirmation
Subtask 30-31-00-710-102-A

A. Test
(1) Do the operational test of the probe ice protection AMM 30-31-00-710-001.

4. Fault Isolation
Subtask 30-31-00-810-076-A

A. If the test gives the maintenance message L STATIC PROBE 7DA3:

do a check of the resistance between pin 2 and pin 1.

(1) If the resistance is more than 13 ohms (open circuit) or less than 10 ohms (short circuit).
(a) Replace the PROBE-L STATIC, 3 [7DA3] , AMM 34-11-16-000-001 and AMM 34-11-16-400-002.
(2) If the resistance is between 10 ohms and 13 ohms:
(a) Replace the PHC-3 [6DA3] , AMM 30-31-34-000-002 and AMM 30-31-34-400-002.
(b) If the fault continues:

do a check and repair the wiring from the PHC 3 (6DA3) to the L static probe 3 (7DA3) pin A/D to pin 2 ASM 303103.

(3) If the fault continues:
(a) Disconnect connector A from PHC 3 and remove ADIRU 3 AMM 34-12-34-000-001.
(b) Do a check of the probe signal wiring ASM 341302 between PHC 3 pin A/X and ADIRU 3 pin AA/4G.
1 If there is no continuity:

Repair the wiring and
Install ADIRU 3 AMM 34-12-34-400-001.

2 If there is continuity:

Replace ADIRU-3 [1FP3] AMM 34-12-34-400-001.

Subtask 30-31-00-710-103-A

B. Do the operational test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:29:36 UTC