EGT System Fluctuation within Limit on Engine 2

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1. Possible Causes
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
Ref. AMM 77-21-43-300-801 EGT Harness - Wire Braid Repair (VRS3812)
Ref. AMM 77-21-43-350-801 EGT Harness and Junction Box Dry-Out Procedure
Ref. AMM 77-21-43-700-010 Functional Test of the EGT Harness, Junction Box and Thermocouples
3. Fault Confirmation
Subtask 77-00-00-710-298-A
A. Test
Not Applicable
4. Fault Isolation
Subtask 77-00-00-810-260-A
A. Find out if the EGT fluctuation occured because of an indication system error. If there is the condition that
follows, go to Para. 4.B.:
(1) EGT fluctuates with no related change in N1 or fuel consumption.
NOTE: A general trend of declining EGT margin associated with a rise in fuel consumption could be a
sign of deteriorating HPT stage 1 outer air seals.
Subtask 77-00-00-810-261-A
B. Do the steps that follow if the condition in Para. 4.A. occurred.
(1) Do a visual inspection of the EGT harness, junction box and the thermocouples.
(a) If the EGT harness is chafed, repair it Ref. AMM 77-21-43-300-801 .
(b) If there is moisture accumulation in the junction box, use hot air or nitrogen to remove the
moisture Ref. AMM 77-21-43-350-801 .
(c) If there are broken stud short circuits because of misplaced safety wire or physical damage other
than harness chafing, remove, replace or correct the applicable hardware.
(2) If you do not find a problem, do the electrical checks of the EGT system Ref.
AMM 77-21-43-700-010 .
(3) If you find a problem with the EGT hardware, replace the applicable hardware and return the engine
to service.
Figure 77(IAE)-00-00-991-00100-13-A- / SHEET 1/1 - N1 Sensor
Figure 77(IAE)-00-00-991-00200-13-B- / SHEET 1/1 - Engine Dedicated Alternator Stator
Figure 77(IAE)-00-00-991-00500-13-A- / SHEET 1/1 - EGT Overtemperature Limits (V2500-A1, V2522-A5, V2524-
A5, V2527-A5, V2527E-A5, V2527M-A5) (Idle and above)
Figure 77(IAE)-00-00-991-00500-13-B- / SHEET 1/1 - EGT Overtemperature Limits (V2530-A5, V2533-A5) (Idle
and above)
Figure 77(IAE)-00-00-991-00600-13-A- / SHEET 1/1 - Turbine Cooling Air Supply Tubes Locations
Figure 77(IAE)-00-00-991-00700-13-A- / SHEET 1/1 - EGT Overtemperature Limits (Idle and below Including Start)
77-20 - (IAE) - TEMPERATURE
77-20-00 - (IAE) - TEMPERATURE
77-20-00 PB 201 CONF 13 - TEMPERATURE - FAULT ISOLATION PROCEDURES [Rev.6 from Feb 2017] 2026.04.04 04:37:50 UTC