As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON LEVELING OFF AT FL 390, CREW NOTED THAT THE EMER PRESS ANNUNCIATOR CAME ON FOR 2 SEC, THEN EXTINGUISHED. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND BOTH ENDS OF THE RAM AIR DUCT DISCONNECTED FROM THE ELBOW IN THE TAIL CONE. A CHECK FLIGHT WAS COMPLETED SATISFACTORILY.