Fault Message:

SLAT PDU

Fault Code:

2750018STD

Associated CAS:

SLAT FAIL
(Caution)

SLAT FAULT
(Caution)

SLAT FLAP FAIL
(Caution)

SLAT FLAP FAULT
(Caution)

SLAT FLAP HALFSPD
(Advisory)

SLAT HALFSPD
(Advisory)

Access CAIMS- active faults to see if one or both SFCUs are reporting the problem.

Fault reported by only one SFCU:

1. Swap SFCUs.

   1. If system checks are good, replace defective SFCU and do close out.
   2. If fault remains, continue with next step.
      NOTE: If necessary perform the clear latched fault after swapping the SFCU.

2. Swap Slat PDU motors.

   1. If system checks are good, replace defective slat PDU motor and do close out.
   2. If fault remains, continue with next step.

3. Perform wiring checks from the SFCU racks as follow:

   Fault reported by the SFCU 1 (SLAT/FLAP CONTROL UNIT 1 STN 493 LHS):

   From	To	Resistance Range	Result
   A124DP1-5	A124DP1-6	0.4050 to 0.2550 ohms
   A124DP1-6	A124DP1-1	0.4050 to 0.2550 ohms
   A124DP1-1	A124DP1-5	0.4050 to 0.2550 ohms
   A124AP1-10	A124AP1-12	9 to 11 ohms
   A124AP1-11	A124AP1-25	45.9 to 56.1 ohms
   A124AP1-24	A124AP1-25	45.9 to 56.1 ohms
   A124AP1-23	A124AP1-25	45.9 to 56.1 ohms

   Fault reported by the SFCU 2 (SLAT/FLAP CONTROL UNIT 2 STN 493 RHS):

   From	To	Resistance Range	Result
   A95DP1-5	A95DP1-6	0.4050 to 0.2550 ohms
   A95DP1-6	A95DP1-1	0.4050 to 0.2550 ohms
   A95DP1-1	A95DP1-5	0.4050 to 0.2550 ohms
   A95AP1-10	A95AP1-12	9 to 11 ohms
   A95AP1-11	A95AP1-25	45.9 to 56.1 ohms
   A95AP1-24	A95AP1-25	45.9 to 56.1 ohms
   A95AP1-23	A95AP1-25	45.9 to 56.1 ohms

   1. If wiring checks are not good, repair defective wiring as required and do close out.
   2. If wiring checks are good, continue with next step.

4. Perform torque/backlash check of the slat system.

   1. If check is normal, go to step 6.
   2. If there is friction or drag in the system, continue with next step.

5. Repair mechanical defects.

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

6. Replace slat PDU.
7. Do close out.

Fault reported by both SFCUs:

1. Energize AC and DC power of one SFCU to clear the latched fault.

   1. If latched fault is clear, go to step 3.
   2. If latched fault remains, continue with next step.

2. Energize the other SFCU.

   1. If latched fault remains, go to step 5.
   2. If no latched fault remains, continue with next step.

3. Operate at half speed by one SFCU only, and confirm if the slats can be operated at half speed by the same SFCU in the other position.

   1. If any SFCU cannot operate at half speed, go to step 5.
   2. If one SFCU can operate at half speed, swap SFCU.

      1. If slats can be operated at half speed by the same SFCU, do close out.
      2. If not, continue with next step.

4. Swap slat PDU motor with any flap PDU motor to the SFCU that latched fault cannot be cleared.
   NOTE: SFCU 1=Slat PDU motor 1 (left), SFCU 2=Slat PDU motor 2 (right).

   1. If system checks are good, replace slat PDU motor and do close out.
   2. If fault remains, continue with next step.

5. Perform torque/backlash check of the slat system.

   1. If check is normal, go to step 7.
   2. If there is friction or drag in the system, continue with next step.

6. Repair mechanical defects.

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

7. Replace slat PDU.
8. Do close out.