What was found
FA NOTED SMELL IN BACK OF AIRCRAFT ON DESCENT. SAME SMELL ON CLIMB OUT BUT WENT AWAY. RAN BOTH PACKS WITH APU AIR FULL HOT FULL COLD, NO ODORS. RAN ENG 1 WITH BOTH PACKS FULL HOT FULL COLD, NO ODORS. RAN ENG 2 WITH BOTH PACKS FULL HOT AND FULL COLD, NO ODORS. REF JRH 2-40-1 . OK FOR SERVICE.