STALL PROTECT FAULT
(Advisory)

A loss of system inputs to the stall computer has caused the Stall Protection System to revert to a more conservative flap setting (flaps 30°).

• L Flap Position Sensor (MPE77)
• R Flap Position Sensor (MPE78)
• Flap Control Unit (FCU) (A124)
• Stall Protection Computer (SPC) (A178)
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW300-27-0058 - Flap Control Unit - CAS Messages Reset procedure (20003 - 20999)

Forum Articles/Infoservice/Newsletter: None

If Flap Control Unit (FCU) PN:2257A0000-02 is installed, reset procedure included in AW300-27-0058 may clear the fault.

1. Check in the MDC in the current faults and fault history pages for problems related to Stall Protection System.

   1. If one of the faults below is reported by the MDC, proceed with their respective troubleshooting before.
   2. If none of the faults below is reported by the MDC, continue with next step.
      Select an MDC Fault/Message:B3-007957 - NO FLAP ANALOG TO SPC [STALL COMPUTER]B3-007961 - NO FCU FLAP INPUT [STALL COMPUTER]B3-007967 - INVALID FLAP INPUT [STALL COMPUTER]

2. Check in the MDC in the current faults and fault history pages for problems related to FLAP CONTROL UNIT.

   1. If one of the faults below is reported by the MDC, proceed with their respective troubleshooting before.
   2. If none of the faults below is reported by the MDC, continue with next step.
      Select an MDC Fault/Message:B3-006677 - FCU INTERNAL FAULT [FLAP CTRL UNIT]B3-007120 - POSITION SENSOR FAULT [L POSITION SNSR]B3-007121 - FPIU POS SENSOR FAULT [L POSITION SNSR]B3-007843 - POSITION SENSOR FAULT [R POSITION SNSR]B3-007844 - FPIU POS SENSOR FAULT [R POSITION SNSR]

3. Reset the following circuit breakers.

   STALL R PWR	CB2-B10
   STALL L PWR	CB1-B10
   FLAP R IND	CB2-B12
   FLAP L IND	CB1-B13
   FLAP CTRL	CB1-B14

4. Reset the FCU by pressing the FCU reset button on the MAINTENANCE TEST control-panel.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

5. Do the Electrical Rigging of the Flap system.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

6. Do wiring check between FCU connectors A124AP1/ A124BP1 and Right Flap Position Sensor connectors A78AP1/A78BP1. Repair/replace as required.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

7. Do wiring check between FCU connectors A124AP1/ A124BP1 and Left Flap Position Sensor connectors A77AP1/A77BP1. Repair/replace as required.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

8. Check internal wiring integrity of both Flap Position Sensors as per the following table. Replace as required.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

   Channel A (connector P1)		Channel B (connector P2)
   Between pin 1 and pin 2	110Ω	Between pin 1 and pin 2	110Ω
   Between pin 3 and pin 4	75Ω	Between pin 3 and pin 4	75Ω
   Between pin 5 and pin 6	75Ω	Between pin 5 and pin 6	75Ω

   NOTE: A swap of both Flap Position Sensors can also be done to confirm a defective Flap Position Sensor.

9. Do wiring check between FCU connectors A124AP1/ A124BP1 and SPC connectors A178AP1 /A178BP1. Repair/replace as required.

   1. If system checks are good, do close out.
   2. If fault remains, continue with next step.

10. Replace SPC.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

11. Replace FCU.
12. Do close out.