What was found
FLT#1923, SJU-DCA. 'STARTED APU - INFLIGHT CAME ON AC HAD DIRTY SOCK SMELL; REMOVED AND REPLACED RECIRCULATION FILTERS REF AMM 21-21-41. PERFORMED INSPECTION OF APU (EXTERIOR) REF AMM 49-00-00-200-811-A, NO DEFECTS NOTED. C/W INFORMATION NOTICE 2017-T015, SECTION B 92). THE AIRCRAFT IS OK FOR SERVICE. ACCOMPLISHED A LEVEL OF DECONTAMINATION OF THE ECS REF AMM 21-00-00-815-802, DETERMINED APU BLEED AS THE SOURCE OF SMELL PER ODOR EVENT DECISION TABLE.'