As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN RECIRCULATION AIR ROW 28 AND AFT IS NON EXISTENT. RT RECIRC FAN RECYCLED AND OPERATING. CHECKED AREA IAW MM FOR RESTRICTOR PROBLEMS. NO AIR FLOW FROM OVERHEAD DIFFUSER DUCT FROM ROW 25 TO 34. GASPER AIR FLOW IS GOOD IN SAME AREA. SUSPECT BLOCKAGE IN THE DIFFUSER DUCT CHANNEL. NO DAMAGE TO DUCT NOTED. REMOVED CTR DIFFUSER FROM ROW 25 TO AFT OF PLANE AND CLEANED. REINSTALLED DIFFUSER. AIRFLOW CHECKED GOOD.