What was found
(AIRCRAFT NOT GROUNDED) DIRTY SOCKS/BURNING CHEMICAL SMELL DURING DECENT AT APPROX 20000 FEET. ELIM OF ODOR CHECKLIST SHOWED. IMPROVEMENT WITH PACK 1 OFF AND PACK 2 ON. / PERFORMED TC 21-000-002, REMOVED AND REPLACED THE APU FCU AS INSTRUCTED. PERFORMED ALL REQUIRED LEAK AND OPS CHECKS, OPS CHECK OK AT THIS TIME, NO LEAKS NOTED AT THIS TIME. NO FURTHER DEFECT NOTED WITH THIS LRU. ALL WORK PERFORM (IRW) AIRBUS A320 AMM 49-32-11-000-003-A & 49-32-11-400-003-A.