As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6356 - BOS-IAD - DURING POST FLIGHT INSPECTION, NOTICED THAT THE RIGHT ACM EXHAUST DUCT WAS MISSING. DUCT APPARENTLY DEPARTED AIRCRAFT DURING CRUISE FLIGHT FROM BOS TO IAD. MAINTENACNE TECHNICIANS VERIFIED THAT THE DUCT WAS MISSING AND REPLACED THE DUCT IAW THE MM PROCEDURES. MAINTENANCE THEN RELEASED AND APPROVED THE AIRCRAFT FOR RETURN TO SERVICE. (M)