Fault Message:

GEN1 OIL OVERTEMP FAULT

Fault Code:

2421126LPS

Associated CAS:

GEN 1 FAIL
(Advisory)

The temperature of the oil in the Generator 1 is above the recommended limits.

• Variable Frequency Generator (VFG) 1 (G1)
• Variable Frequency Generator (VFG) 1 Oil Cooler
• Generator Control Unit (GCU) 1 (A56)

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 GCU 1, GCU 2, GCU 3, GCU 4 and the APU GCU into a different position (for troubleshooting only). You can monitor the GCU faults in the CAIMS via the active fault page.
• The GCU NVMs can only be downloaded at position #2 or #3.

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

   • 2421200LPS - GEN1 DRIVE SHAFT FAIL/INVALID %N2
   • 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 OMS fault messages and VFG condition(s) perform RIL GX-0198
   2. If there is NO combination, continue with next step.

2. On the VFG 1, record the oil level in relation to the “ADD OIL” line on the sight glass.

   1. If oil level is above add oil line, replace VFG 1.
   2. If oil level is below add oil line, continue with next step.

3. Perform general visual inspection of the applicable main-generator oil tubes.

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

4. Disconnect GCU 1 connector A56P2 and VFG 1 connector G1P1. Perform a continuity check as follows:

   From	To	Result
   A56P2-24	Ground
   A59P2-60	Ground

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

5. Perform a continuity check between GCU 1 and VFG 1 as follows:

   From	To	Result
   A56P2-24	G1P1-A
   A56P2-60	G1P1-M

6. Interchange GCU 1 with GCU 2. Is the fault still present?

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

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