What was found
BOTH ON GRND BEFORE DEPARTURE AND ON ARRIVAL DESCENDING PASS 8K' AGL A MUSTY ODOR IN CABIN OCCURED. CABIN CREW REPORTED REPEAT FROM PREVIOUS FLIGHT UNPLEASANT ODOR DISSIPATED IN CRUISE.REMOVED BORO PLUGS HPC 4/5, HPC 3/4, HPC 2/3 & HPC 1/2 PERFORMED BSI OF #2 ENG. HPC BLADES 1-3 AND 4-6 PER A350AMM A-72 -41-62 AND A-72-41-63, NO RESTRICTIVE DAMAGE NOTED. REINSTALLED BORO PLUGS PER AMM 72-41. T/S PER A350 TSM A350-A-21-21-XX-5Y001-421A-A, PERFORMED TEST IN TABLE 7, TEST ONE HAD SMELL DISSIPATED AFTER APPROX 2 MIN, TEST 4 WAS VERY STRONG POSSIBLE OIL SMELL, TEST 6 HAD FAINT SIMILAR SMELL. TEST 2, 3, AND 5 WAS NORMAL. OPEN #2 ENGINE AND INSPECTED FOUND OIL SEEPAGE JUST AFT OF ENGINE FAN. REMOVED AND REPLACED FWD CABIN RECIRC FILTERS PER AMM 21-51 . ITEM IS OKAY FOR SVC. R/R ALL 4 AFT RECIRC FAN FILTERS PER 21-51 (335114) DECONTAMINATION INSP STILL REQ. RAN ENGINES FOR 1 HOUR REF AMM 21-52 STILL SMELLS. PERFORMED PACK BURN OUT POST APU CHANGE, CABIN SMELLS CLEAN. PERFORMED ENG RUN & USED ENG BLEED PER AMM 71-XX, CABIN SMELLED CLEAN. ALL RECIRC FILTERS CHANGED PER AMM 21-21. CLEANED ECS PER AMM 21-52. ODI STEPS 1, 2, 3, & 4 C/W. O/C OK FOR SVC.