What was found
(CAN) DURING CRUISE AT FLIGHT LEVEL 360 EXPERIENCED SOME TURBULENCE AND AIRSPEED DECREASED. PUSHED TRUST LEVERS FORWARD AND THE NR 1 ENGINE N1 SPEED WHITE NEEDLE FLUCTUATED AND DROPPED - 5 PERCENT. SECOND TIME PUSHED TRUST LEVERS FORWARD AGGRESSIVELY AND NR 1 ENGINE N1 ROLLED BACK TO ABOUT 60 PERCENT AND THEN STABILIZED. A/C YAWED, N1 ON ENGINE NR 1 WAS NORMAL FOR REMAINDER OF FLIGHT. HMU REPLACED IAW AMM 73-21-10 AND GROUND TEST CARRIED OUT SATISFACTORILY. EVENT CONFIRMED WITH GE REMOTE DIAGNOSTICS GAS PATH ADVISORY WHICH IS ATTACHED. FOLLOW-UP FDR DATA DOWNLOAD AND IT"S ANALYSIS TO BE CARRIED OUT.