W DOC AIRBUS | TSM A320F

APU AUTO SHUTDOWN - LOSS OF SPEED, Speed Sensor Fault (131-9(A))

TASK 49-00-81-810-845-A
APU AUTO SHUTDOWN - LOSS OF SPEED, Speed Sensor Fault (131-9(A))

1. Possible Causes
  • SPEED SENSOR SHOWS AMPLITUDE FAILURE
  • damage/contamination of the electrical connector P26
  • SPEED SENSOR 1 and/or 2
  • aircraft wiring
  • ELECTRONIC CONTROL BOX [59KD]
  • SPEED SENSOR (8060KM) 1 and/or 2
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
MULTIMETER - STANDARD
 B. Referenced Information
REFERENCE
DESIGNATION
AMM 49-00-00-860-008
APU Start by External Power
ASM 496104
AMM 49-61-34-000-003
Removal of the Electronic Control Box (ECB) (131-9(A))
AMM 49-61-34-400-003
Installation of the Electronic Control Box (ECB) (131-9(A))
AMM 49-71-13-000-003
Removal of the Speed Sensors (131-9(A))
AMM 49-71-13-400-003
Installation of the Speed Sensors (131-9(A))
3. Fault Confirmation
Subtask 49-00-81-710-180-A ** ON A/C NOT FOR ALL
A. Read-out of ECB Trouble-Shooting Data
   (1) Put the APU MASTER SW to the ON position.
   (2) Get access to the APU SHUTDOWN report.
   (3) Push the '>' adjacent to LRU DATA:
  • the MCDU menu shows
    SPEED SENSOR SHOWS AMPLITUDE FAILURE

   (4) Start the APU and apply Bleed Air for 20 seconds, minimum AMM 49-00-00-860-008.
4. Fault Isolation
Subtask 49-00-81-810-126-A ** ON A/C NOT FOR ALL
A. If an APU auto shutdown occurs during the APU operation and the APU SHUTDOWN report gives the maintenance message:

LOSS OF SPEED
SPEED SENSOR P26

associated with the Fault Code Number (FCN) 1

  • do a check and repair for damage/contamination of the electrical connector P26 of the SPEED SENSOR 1/2 (P26).
   (1) If the electrical connector P26 is damaged/contaminated:
  • do a repair/cleaning
   (2) If the electrical connector is OK:
  • use a MULTIMETER - STANDARD to do a resistance check across
    pin 1 and pin 2; required value < 25 Ohms
    and
    pin 3 and pin 4; required value < 25 Ohms
    and
    pin 1/pin 3 and pin 5; required value > 100 kOhms.

     (a) If the resistance values are out of the specified limits:
     (b) If the resistance values are in the specified limits:
  • do a check and repair of the aircraft wiring from
    the ECB (59KD) AB/E6,E7 to the electrical connector P26/1,2 (SPEED SENSOR 1)
    and
    the ECB (59KD) AB/D3,D4 to the electrical connector P26/3,4 (SPEED SENSOR 2)
    ASM 496104.
       1 If the fault continues:
Subtask 49-00-81-810-126-B ** ON A/C NOT FOR ALL
A. If an APU auto shutdown occurs during the APU operation and the APU SHUTDOWN report gives the maintenance message:

LOSS OF SPEED
SPEED SENSOR (8060KM)

associated with the Fault Code Number (FCN) 1

  • do a check and repair for damage/contamination of the electrical connector P26 of the SPEED SENSOR 1/2 (8060KM).
   (1) If the electrical connector P26 is damaged/contaminated:
  • do a repair/cleaning
   (2) If the electrical connector is OK:
  • use a MULTIMETER - STANDARD to do a resistance check across
    pin 1 and pin 2; required value < 25 Ohms
    and
    pin 3 and pin 4; required value < 25 Ohms
    and
    pin 1/pin 3 and pin 5; required value > 100 kOhms.

     (a) If the resistance values are out of the specified limits:
     (b) If the resistance values are in the specified limits:
  • do a check and repair of the aircraft wiring from
    the ECB (59KD) AB/E6,E7 to the electrical connector P26/1,2 (SPEED SENSOR 1)
    and
    the ECB (59KD) AB/D3,D4 to the electrical connector P26/3,4 (SPEED SENSOR 2)
    ASM 496104.
       1 If the fault continues:
Subtask 49-00-81-710-181-A ** ON A/C NOT FOR ALL
B. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:34:35 UTC
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