What was found
STRONG SCENT OF BURNING ODOR AFTER LANDING & AFTER BLEED CHANGE OVER FROM ENGINES TO APU. REPAIRED RISER DUCT BETWEEN 16CD AND 17CD IAW ERS-CR-25-047 PTA.VERIFIED THAT NR 2 RECIRCULATION FAN CHECK VALVE IS INSTALLED PROPERLY IAW AMM 21-22-10. OPS AND LEAK CHECKED GOOD. NO BLOCKAGE OR OBSTRUCTIONS NOTED IN RT RECIRCULATION FAN DUCTING IAW AMM 21-23-34. OPS AND LEAK CHECKED GOOD. INSPECTED RT RECIRCULATION FAN INLET IAW AMM 21-23-25. NO OBSTRUCTIONS NOTED WITH STRONG AIRFLOW GOING INTO INLET.