EPR Fluctuations on both Engines during Flight

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1. Possible Causes
· SENSOR-TAT, 1 ( 11FP1 )
2 Job Set-up Information
A. Referenced Information
REFERENCE DESIGNATION
71-00-00-810-832-A EPR Fluctuations on Engine 1 during Flight
71-00-00-810-833-A EPR Fluctuations on Engine 2 during Flight
Ref. AMM 34-11-18-710-001 Test of the TAT Sensor without the CFDS
3. Fault Confirmation
Subtask 71-00-00-710-069-A
A. Not applicable
4. Fault Isolation
Subtask 71-00-00-810-066-A
A. If the fault symptom is identified by the crew observation significant EPR fluctuation on both engines:
(1) Check for fault messages related to any of the following system:
· engine EPR sensing system
· wing anti-ice system
· pack flow control valves
· engine air inlet anti-ice valve
· engine bleed system
If fault messages are found, carry out troubleshooting accordingly.
(2) If no faults found, do a test of the SENSOR-TAT, 1 ( 11FP1 ) without CFDS, Ref.
AMM 34-11-18-710-001 .
If faults found, repair per applicable trouble shooting procedures.
(3) If no faults are logged and if the EPR fluctuations were observed in flight independently of the flight
phase, independently of ATHR engagement and were linked to bleed fluctuations greater than 38-56
psig:
· Identify the engine which featured the highest engine parameter fluctuations
· For the engine 1, do the check for EPR fluctuations on engine 1 (Ref. TSM 71-00-00-810-832)
· For the engine 2, do the check for EPR fluctuations on engine 2 (Ref. TSM 71-00-00-810-833) [Rev.6 from Feb 2017] 2026.04.04 04:35:01 UTC