As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
F/AS REPORT STRONG SOUR SMELL IN AFT CABIN MOVING FORWARD AND GETTING STRONGER WHILE DESCENDING THROUGH 81000 FEET AT IDLE POWER, PACK 2 ISOLATED AND F/AS REPORT SMELL DECREASED-REF TSM 05-50-00-810-831-A ACCOMPLISHED DECONTAMINATION OF THE ECS. IAW AMM 21-00-00-615-001-A. PERFORMED IDLE RUN OF BOTH ENGINES IAW AMM 71-00-00. FOUND NO SMELL OF SIGNS OF ODOR. A/C OK TO RETURN SERVICE. AEROTRACER NK10519T