As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT AT FL 26.0 MADE AN EMERGENCY DESCENT DUE TO LOSS OF CABIN PRESSURIZATION. REPLACED LEFT AND RIGHT PRESSURIZATION VALVES. PERFORMED PRESSURIZATION CHECK PER MM 21-31-00 WITH ENGINES 2 AND 3 RUNNING. PRESSURIZED TO 8.0 PSID, NO LEAK OR DEFECTS NOTED.