Fault Message:

GEN1 DRIVE SHAFT FAIL/INVALID % N2

Fault Code:

2421200LPS

Associated CAS:

GEN 1 FAIL
(Advisory)

Variable Frequency Generator (VFG) 1 has tripped off-line or will not come on-line.

• Generator Control Unit (GCU) 1 (A56)
• Variable Frequency Generator (VFG) 1 (G1)
• Associated Wiring

Advisory Wire/Service Bulletin: 

• AW700-24-0598 - Variable Frequency Generator (VFG) GL511-1103-9 - Failure

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 1 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 swap 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 messages are active:

   • 2421126LPS - GEN1 OIL OVERTEMP FAULT
   • 2421124LPS - GEN1 [DIFF PROTECTION FEEDER]

   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 fault messages and VFG condition(s) perform RIL GX-0198
   2. If there is NO combination, continue with next step.

2. Interchange GCU #1 with GCU #2 (physically or using the GCU patch cable).
   NOTE: Use CAIMS to monitor the fault on GCU.

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

3. Disconnect G1P1 (VFG 1) and A56P1 (GCU 1). Do a continuity check as follows:

   From	To	Result
   A56P1-E	Ground
   A56P1-F	Ground
   A56P1-G	Ground

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

4. Do a continuity check between GCU 1 and VFG 1 as follows:

   From	To	Result
   A56P1-E	G1P1-G
   A56P1-F	G1P1-C
   A56P1-G	G1P1-L

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

5. Disconnect connector A54P6 (ACPC) and connector A56P2 (GCU 1). Perform a wiring check between A56P2 and A54P6 as follows:
   

   From	To	Result
   A56P2-9	A54P6-a
   A56P2-15	A54P6-b

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

6. Replace VFG 1.
7. Do close out.