What was found
AT 6000' ON DECENT INTO (ENGINES IDLE) DTW (PACKS ON) ODOR ( ACRID) RETURNED TO FLIGHT DECK ONLY. C/A: PERFORMED JOB CARD 0550-2002, CORDINATED WITH MCC TO DO DECONTAMINATION AND INSPECTION OF ENGINES. PERFORMED BLACK LGHT CHECK OF #1 ENG BLEED SYSTEM. NO SIGNES OF CONTAMATION , NO EXTERNAL SIGNS OF LEAKS BOTH ENGINES. APU DETERMINED TO BE CAUSE , AS EVIDENCE OF OIL PRESENT. PERFORMED CORRECTIVE ACTION TYPE 1 PER A320 JIC 2100-2005 UP TO STEP 12. COMPLETED ALL STEPS OF CARD 2100-2005, BURN OUT COMPLETE STAGE 1&2 COMPLETE REMOVED SPINNER NO OIL RESIDUE NOTICED. MCC NOTIFIED. OK FOR SERVICE. NO ODOR OBSERVIED.