What was found
NR 1 ENGINE N1 FLUCUATED AFTER TAKEOFF AT 10 TO 11K FT, THEN 3 TIMES IN CRUISE, NOT HIGHER THAN 101 PERCENT. ON DESCENT WITH POWER BACK IT STARTED FLUCUATING SEVERAL TIMES RAPIDLY. TURNED NR 1 FADEC OFF, NO DIFFERENCE, SHUT NR 1 ENGINE DOWN 35 MILES OUT OF DTW. MAINTENANCE REPLACED NR 1 HMA ASSEMBLY IAW ALLIED SIGNAL EMM 72-00-61. OPS, LEAK, SECURITY CHECK GOOD.