APU AUTO SHUT DOWN - NO ACCELERATION, Back-Up Start-Contactor Fault (APS 3200)

TASK 49-00-00-810-879-A
APU AUTO SHUT DOWN - NO ACCELERATION, Back-Up Start-Contactor Fault (APS 3200)

1. Possible Causes

FUSE-APU START [6KA]
wiring
CONTACTOR-BACK-UP START [10KA]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ESPM 2052210
ESPM 2053210
AMM 49-00-00-710-008	Operational Test of the APU
AMM 49-42-00-960-001	Replacement of the APU Start Fuse
ASM 494201
AMM 49-42-55-000-001	Removal of the Start Contactors
AMM 49-42-55-400-001	Installation of the Start Contactors

3. Fault Confirmation
Subtask 49-00-00-710-206-A ** ON A/C NOT FOR ALL

A. Do the operational test of the APU AMM 49-00-00-710-008.

4. Fault Isolation
Subtask 49-00-00-810-130-B ** ON A/C NOT FOR ALL

A. If the APU Last Leg Report gives the maintenance message:

CURRENT LIMITER (6KA) / CONTACTOR (10KA):
Fault Code Number: 051
Additionally:
Fault Code Number: 126

NOTE: The APU SHUTDOWNS report gives the maintenance message:
NO ACCELERATION - CURRENT LIMITER (6KA) / CONTACTOR (10KA)
APU Auto Shut Down Fault Code Number: 051

do a check for 28VDC at the BACK-UP START CONTACTOR (10KA) A/D ASM 494201.

(1) If the power supply is not OK:

do a check and replace the FUSE-APU START [6KA] AMM 49-42-00-960-001.

(a) If the fault continues:

do a check and repair the wiring from the FUSE (6KA) to the BACK-UP START CONTACTOR (10KA) A/D ASM 494201 ESPM 2052210 ESPM 2053210.

(2) If the power supply is OK:

replace the CONTACTOR-BACK-UP START [10KA] AMM 49-42-55-000-001 and AMM 49-42-55-400-001.

Subtask 49-00-00-710-207-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:23 UTC