What was found
NR 4 FAN BLADE ON NR 2 ENGINE S/N JB1AEA4305 MISSING POLYURETHANE COAT. REMOVED AND REPLACED NR 4 FAN BLADE, PER AMM 72-11-03-400-801-A. FUNCTIONAL TEST FAN TRIM BALANCE AMM TASK 71-00-00-710-807-A PENDING. PERFORMED FUNCTION TEST (FAN TRIM BALANCE), PER AMM 71-00-00-710-807-A THRU STEP 4.A.(7) CONT. AT 80% N1 SPEED CU'S WAS 0.6 AND MAG WAS 0.2168. AT 91% (MAX N1 SPEED) CU'S WAS 1.0 AND MAG WAS 0.3242. NEED TO CONTINUE FROM STEP 4.A.(8) 9/13/20 17942. PER ENGINEERING, SWAPPED BLADES 3 (SN - JB1AEA4282) AND 14 (SN - JB1AEA1972). PERFORMED FAN TRIM BALANCE, PER AMM 71-00-00-710-807-A MAX MAG NOTED=0.0854. OK FOR SERVICE.