As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 2533 DCA-PBI. DESENDING FROM 10000 TO 4000 THE FLIGHT CREW ENCOUNTED DIRTY SOCK ODOR THRUST WAS AT NEAR IDLE AND THE APU WAS NOT RUNNING ODOR WAS MILD TO MODERATE PIC WILL COMPLETE FUME EVENT REPORT AS NECESSARY.;COMPLIED WITH INFORMATION NOTICE 2017-T015 STEP 1 ISOLATED FAULT TO TYPE 10 AMBIENT AIR ODOR WITH OCCURS DURING THE FLIGHT INCREASES THE HUMIDITY OF THE AIR A/C OK FOR CONT SVC.