As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ON INITIAL DESCENT AS POWER REDUCED TO IDLE DEPARTING FL360, STRONG ODOR NOTICED ON FLIGHT DECK AND REPORTED BY F/A`S IN CABIN. AT INTERMEDIATE LEVEL OFF WITH POWER ABOVE IDLE ODOR DISSIPATED SOMEWHAT-EVERY TIME POWER REDUCED ODOR RETURNED. BOTH PACKS AUTO ENGINE BLEEDS ON APU OFF APU BLEED OFF. CATEGORY A DIRTY SOCK, RANCID CHEESE ODOR-NO IRRITATION TO EYES OR NOSE. REPLACED NR 1 ENGINE IAW TASK CARD 19L40071001.