Failure of the Bleed Bias System on Engine 1

TASK 75-30-00-810-829-B
Failure of the Bleed Bias System on Engine 1

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 73-21-60-000-001	Removal of the Electronic Control Unit (ECU)
AMM 73-21-60-400-001	Installation of the Electronic Control Unit (ECU)
AMM 73-29-00-710-040	Operational Test of the FADEC on the ground (with Engine Motoring)
AMM 75-34-10-000-001	Removal of the Bleed Bias Transducer
AMM 75-34-10-400-001	Installation of the Bleed Bias Transducer
AMM 75-34-20-000-001	Removal of the Bleed Bias Venturi
AMM 75-34-20-400-001	Installation of the Bleed Bias Venturi

3. Fault Confirmation
Subtask 75-30-00-710-116-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the operational test of the FADEC 1A on the ground (with engine non motoring) AMM 73-29-00-710-040.

4. Fault Isolation
Subtask 75-30-00-810-083-A ** ON A/C NOT FOR ALL

A. If the CLASS 3 FAULTS page gives the maintenance message CWB3, WB3 SENS, J15:

do a check for leakage or blockage of the pressure tubes between the bleed bias transducer and the bleed bias venturi.

(1) If the fault continues:

(2) If the fault continues:

(3) If the fault continues:

Subtask 75-30-00-810-083-B ** ON A/C NOT FOR ALL

A. If the CLASS 3 FAULTS page gives the maintenance message VTURI, BLD SNSR, ECU:

do a check for leakage or blockage of the pressure tubes between the bleed bias transducer and the bleed bias venturi.

(1) If the fault continues:

(2) If the fault continues:

(3) If the fault continues:

Subtask 75-30-00-710-117-A ** ON A/C NOT FOR ALL

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

[Rev.8 from Aug 2018] 2026.04.04 04:37:09 UTC