Message Name:

FLAP JAM

Message Code:

B3-006689

FCU calculate hard shaft rotation speed using LH and RH position sensor values.

• Trigger, speed < 14 rpm for > 0.5 seconds.
• CAS message FLAPS FAULT - Category: RESETTABLE - Reset: Flap lever re-selection.
  NOTE:Three (3) unsuccessful reset attempts will change the failure category to CRITICAL.
• Monitor is valid only when system is commanded to drive the Pressure Off Brake (POB) solenoid energized.

• Flap Power Unit (FPU) (A123)
• FPU (A123)/Solenoid Valve
• Flap Transmission Brake (FTB)/Solenoid Valve
• Associated Wiring

Advisory Wire/Service Bulletin: None

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

NOTES: 

• Flap Control Unit (FCU) (A124) & Flap Position Indication Unit (FPIU) are powered by the Electrical Bus, as shown in Table 1-1. 
  

  Table 1-1 Flap PWR Source

  Left FPIU	FCU	Right FPIU
  L ESS Bus	L ESS Bus	R ESS Bus

• If the DCPC receives the Flight signal from the PSEU with the aircraft on the ground and the engine driven generators are not producing power the Auto load shed will happen. This scenario could cause the Flap system to post CAS messages and MDC Faults associated with the Flap system. Refer to the Observed Fault 246OBS002 - AUX BUS LOAD SHED ON GND.
• Customers have reported a FLAPS FAULT (Caution) CAS message caused by a flap jammed, which occurs after every Flap Transmission Brake (FTB) check initiated manually or automatically at every 20 flight cycles.
• At the end of the FTB test-sequence, Torque Limiter of the right actuator will lockout. No related CAS message will show until a flap retraction is commanded. Then a FLAPS FAULT (Caution) CAS message will appear. The message is resettable with a Flap commanded into extended direction.
• During FTB check, the system is commanded with full torque against closed FTBs. First LH side and then RH side. At the end of the test sequence, because of a weakened EHSV inside the Flap Power Unit(FPU), energy (torque) is still present in the system and held by the RH FTB. When the FLAP is commanded to the extract direction, RH FTB is released and this energy is transmitted to the torque transmitter who is forced to lockout. TL lockout can always be reset by Flap Jam reset procedure (reverse lever command).
• If you experience the problem described above, the Flap Control Unit NVM can be downloaded and sent to Bombardier for analysis. The Analysis can help to confirm if the FPU should be replaced.

1. Attempt to reset the flaps using the Flap Reset on the left galley rotary test switch, near entry door. If unable to reset, engage the Alternate Flaps button with the left hydraulic system pressurized, and attempt another reset using the Flap Reset switch on the left galley.

   1. If system checks are good, do close out.
   2. If unable to clear, continue with the next step.

2. Do the AMM Task 27−52−00−820−801 - Electrical Rigging of the Flap System.
3. Do the flaps extend or retract as commanded?

   1. If YES, do close out.
   2. If NO, continue with the next step.

4. Do Wiring Check of the Flap Transmission Brake (FTB) Solenoid as follows:
   NOTE: # 1 & # 2 Solenoid Valves are LRUs and replaceable.

   FTB	From	To	Expected Results Resistance	Results
   Alternate Flaps Left Solenoid #1	A203J1-1	A203J1-2	≊ 53.6 - 60.4 Ω
   Normal Flaps Left Solenoid #2	A203J2-1	A203J2-2	≊ 53.6 - 60.4 Ω
   Alternate Flaps Right Solenoid #1	A204J1-1	A204J1-2	≊ 53.6 - 60.4 Ω
   Normal Flaps Right Solenoid #2	A204J2-1	A204J2-2	≊ 53.6 - 60.4 Ω

5. Are the resistance values acceptable?

   1. If YES, continue with the next step.
   2. If NO, replace the defective FTB Solenoid Valve.

6. Do Wiring Check as follows:
   -Release the Flap Transmission Brake with the MDC (AMM 27-52-00-720-802) and record voltages at each connector.
   -Check each with Normal and Alternate flaps. Should be approx 28 VDC.
   

   FTB	From	To	Expected Results	Results
   Alternate Flaps Left Solenoid #1	A203P1-1	GND	28V DC
   Normal Flaps Left Solenoid #2	A203P1-1	GND	28V DC
   Alternate Flaps Right Solenoid #1	A204P2-1	GND	28V DC
   Normal Flaps Right Solenoid #2	A204P2-1	GND	28V DC

7. Are voltage values acceptable?

   1. If YES, continue with the next step.
   2. If NO, repair the associated wiring between the FCU and FTB as required.

8. Does the Flap Jam fault remain active?

   1. If YES, continue with the next step.
   2. If NO, do close out.

9. Do Wiring Check of Flap Power Unit (FPU) Solenoids as follows:
   

   FPU	From	To	Expected Results	Results
   POB Solenoid	A123J1-4	A123J1-5	≊ 53.6 - 60.4 Ω
   Solenoid #2	A123J1-1	A123J1-2	≊ 53.6 - 60.4 Ω
   EHSV Solenoid	A123J1-7	A123J1-8	≊ 53.6 - 60.4 Ω
   Solenoid #1	A123J2-1	A123J2-2	≊ 53.6 - 60.4 Ω

10. Are Resistance values acceptable?

    1. If YES, continue with the next step.
    2. If NO, replace defective FPU Solenoid Valve.

11. If fault remains, continue with the next step.
12. Do the AMM Task 27−52−19−710−801 - Operational Test of the Flap Transmission Brake.
    NOTE: If the AMM test does not pass, it is very likely that either the left or right FTB has failed.
13. Interrogate the MDC looking for MDC Faults associated with the FTB. If any are active, troubleshoot and resolve.

    1. B3-276334 - L FTB FAULT
    2. B3-276353 - R FTB FAULT

14. Do close out.