APU AUTO SHUT DOWN - REVERSE FLOW, Bleed Flow Transducer Fault (APS 3200)

TASK 49-00-00-810-933-A
APU AUTO SHUT DOWN - REVERSE FLOW, Bleed Flow Transducer Fault (APS 3200)

1. Possible Causes

COMPRESSOR DISCHARGE-PRESSURE SNSR P24
aircraft wiring
ELECTRONIC CONTROL BOX [59KD]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ESPM 2052210
ESPM 2053210
ESPM 205321A
AMM 49-00-00-710-008	Operational Test of the APU
AMM 49-51-19-000-002	Removal of the Sensor - Compressor Discharge Pressure (APS 3200)
AMM 49-51-19-400-002	Installation of the Sensor - Compressor Discharge Pressure (APS 3200)
ASM 496102
AMM 49-61-34-000-002	Removal of the Electronic Control Box (ECB) (APS 3200)
AMM 49-61-34-400-002	Installation of the Electronic Control Box (ECB) (APS 3200)

3. Fault Confirmation
Subtask 49-00-00-710-302-B ** ON A/C NOT FOR ALL

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

4. Fault Isolation
Subtask 49-00-00-810-240-B ** ON A/C NOT FOR ALL

A. If an APU auto shutdown occurs during the operational test of the APU and the APU SHUTDOWNS report gives the maintenance message

REVERSE FLOW - BLEED FLOW XDCR P24

replace the COMPRESSOR DISCHARGE-PRESSURE SNSR P24 AMM 49-51-19-000-002 and AMM 49-51-19-400-002.

NOTE: Do a check and make sure that the orifices and the lines which are connected to the compressor discharge pressure sensor are not clogged. Clean if necessary.

(1) If the fault continues:

do a check and repair the aircraft wiring from the ECB (59KD) AB/A1, A4, B2, B3, A2, A3 to the COMPRESSOR DISCHARGE PRESSURE SNSR P24/1, 2, 3, 4, 5, 6 ASM 496102 ESPM 2052210 ESPM 2053210 ESPM 205321A.

(2) If the fault continues:

replace the ELECTRONIC CONTROL BOX [59KD] AMM 49-61-34-000-002 and AMM 49-61-34-400-002.

Subtask 49-00-00-710-303-B ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:34:26 UTC