What was found
DURING DESCENT WITH ENGINE AT IDLE, ENGINE NR 1 N1 VERRIED BETWEEN 38 AND 48% WITH ASSOCIATED RISES IN N2 AND FUEL FLOW AND ENGINE 2 NORMAL. AUTO THROTTLES STAYED AT IDLE DURING THESE EPISODES, EVENT RECORDER PUSHED. PERFORMED PIME BITE, FOUND MESSAGE 354 28-A AND 354 28-B HPTC, ITEM TRANSFERRED TO MEL 75-24-01, MAINTENANCE ITEMS C/W HPTCC CAP AND STOWED. REMOVED AND REPLACED ENG TCC VALVE AS PER AMM 75-24-01, RAN ENG 71-00-00, TEST 12 PERFORMED OPS CHECK GOOD.