Message Name:

GEN2 [DIFF PROTECTION FEEDER]

Message Code:

2422124LPS

Associated CAS:

GEN 2 FAIL
(Advisory)

Variable Frequency Generator (VFG) 2 has tripped off-line or will not come on-line.

• AC Power Center (ACPC) (A54)
• Generator Control Unit (GCU) 2 (A57)
• Variable Frequency Generator (VFG) 2 (G2)
• Associated Wiring

Advisory Wire/Service Bulletin: 

• AW700-24-0598 - Variable Frequency Generator (VFG) GL511-1103-9 - Failure
• AW700-24-0572 - "GEN FAIL" associated with fault message "Open Circuit TR2/TR3"
• AW700-24-0655 - Variable Frequency Generator Harness Low Clearance to Hydraulic/Fuel Lines

Full Throttle Blog/Forum Articles/Infoservice/Newsletter:

• REFERENCE INSTRUCTION LETTER (RIL) GX-0198 - Return to service following VFG bearing failure and/or VFG housing rupture

Flight Operation Notifications Manual (FONM): None

NOTES: 

• Prior to T/S procedures, perform a visual of generator 2 for heat distress. Confirm if the heat exchanger is blocked  with FOD.
• A GCU patch cable (GSE REF # 24X-24-02) can be used to interchange GCUs 1, 4 and 5 into position 2 or 3 (for troubleshooting only).

• The GCU NVMs can only be downloaded at position #2 or #3.

1. Access CAIMS and check if the following faults are active:

   • 2422126LPS - GEN2 OIL OVERTEMP FAULT
   • 2422200LPS - GEN2 DRIVE SHAFT FAIL/INVALID %N2

   Inspect the VFG for the following:

   • VFG oil filter bypass indicator tripped, and/or
   • Metal particles in the oil lines, and/or
   • VFG end frame cracked or breached, and/or
   • Oil sight glass cracked

   1. If there is a combination of the listed CAIMS active fault and VFG condition(s) perform RIL GX-0198
   2. If there is NO combination, continue with next step.

2. Access CAIMS active faults. Are there any ACPC related messages?

   1. If YES, troubleshoot these messages first.
   2. If NO, continue with next step.

3. Interchange GCU 2 with GCU 3 (physically or using the GCU patch cable). Is the fault still present?
   

   1. If YES continue with next step.
   2. If fault remains, replace defective GCU and do close out.

4. Disconnect GCU 2 connector A57P2 and VFG 2 connector G2P1. Do continuity check as follows:

   From	To	Result
   A57P2-41	Ground
   A57P2-42	Ground
   A57P2-50	Ground
   A57P2-40	Ground

   1. If there is continuity, repair defective wiring as required.
   2. If there is NO continuity, continue with next step.

5. Do continuity check between GCU2 and VFG2 as follow:

   From	To	Result
   A57P2-41	G2P1-F
   A57P2-42	G2P1-E
   A57P2-50	G2P1-J
   A57P2-40	G2P1-D

   1. If there is continuity, continue with next step.
   2. If there is NO continuity, repair defective wiring as required.

6. Disconnect ACPC connector A54P7. Do a continuity check as follow:

   From	To	Result
   A57P2-49	Ground
   A57P2-57	Ground
   A57P2-63	Ground
   A57P2-62	Ground

   1. If there is continuity, repair defective wiring as required.
   2. If there is NO continuity, continue with next step.

7. Do a continuity check between GCU 2 and ACPC as follows:

   From	To	Result
   A57P2-49	A54P7-E
   A57P2-57	A54P7-F
   A57P2-63	A54P7-G
   A57P2-62	A54P7-H

   1. IF thee is continuity, continue with next step.
   2. If there is NO continuity, repair defective wiring as required.

8. Disconnect VFG #2 (T1, T2 and T3) and ACPC VFG2-A, B and C.
9. Do an Insulation check using a megger as follows:
   Caution: Before using the megger, make sure both sides of cable are disconnected. Failure to do that may damage the equipment

   From	To	Expected Result	Result
   VFG2-T1	Ground	No Continuity
   VFG2-T2	Ground	No Continuity
   VFG2-T3	Ground	No Continuity

   1. If there is continuity repair defective wiring and do close out.
   2. If there is no continuity, continue with next step.

10. Do an Insulation check using a megger as follows:
    Caution: Before using the megger, make sure both sides of cable are disconnected. Failure to do that may damage the equipment

    From	To	Expected Result	Result
    VFG2-T1	VFG2-T2	No Continuity
    VFG2-T1	VFG2-T3	No Continuity
    VFG2-T1	VFG2-G	No Continuity
    VFG2-T2	VFG2-T3	No Continuity
    VFG2-T2	VFG2-G	No Continuity
    VFG2-T3	VFG2-G	No Continuity

    1. If there is continuity repair defective wiring and do close out.
    2. If there is no continuity, continue with next step.

11. Do a continuity check as follow:

    From	To	Expected Result	Result
    VFG2-T1	ACPC VFG2-A	Continuity
    VFG2-T2	ACPC VFG2-B	Continuity
    VFG2-T3	ACPC VFG2-C	Continuity
    VFG2-G	Ground	Continuity

    1. If there is continuity, continue with next step.
    2. If there is no continuity, repair defective wiring as required.

12. Interchange VFG 1 with VFG 2. Is the fault still present?

    1. If YES, continue with next step.
    2. If NO, replace defective VFG.

13. Replace ACPC.
14. Do close out.