As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ONE HALF OF EMERGENCY PRESSURIZATION CHECK VALVE INOPERATIVE DUE TO USE OF RTV SEALANT INSTEAD OF GASKET. THE APPLIED RTV SEALANT OOZED INTO CHECK VALVE, DURING THE INSTALLATION PROCESS AND SEALED FLAPPER IN THE CLOSED POSITION. R & R EMERGENCY PRESSURIZATION CHECK VALVE IAW 21-22-00.