As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING GVI OF RT PACK AND RAM AIR SYSTEM, FOUND RT PRIMARY PLENUM HEAT EXCHANGER DIFFUSER CHECK VALVE DOOR AND HINGE MISSING, AND DEPARTED AIRCRAFT. REF L/P 11933022 FOR PARTS DEPARTING A/C CONDITIONAL INSPECTION. GROUNDED - YES. REPLACED MISSING DOOR AND HINGE LISTED ABOVE REF CMM 21-50-70.