MD82 FLC OPERATED ACFT WITHOUT THE AIRWORTHINESS CERTIFICATE INSTALLED.

Narrative

ACFT WAS RELEASED FROM MAINT AFTER A 'C' CHK. ACFT LOGBOOK CONTAINED A SIGNATURE CERTIFYING ACFT WAS RELEASED AND IN AIRWORTHY CONDITION. AIRWORTHINESS CERTIFICATE; REGISTRATION AND FEE PERMIT WAS DISPLAYED ON INSIDE OF COCKPIT DOOR; BUT AIRWORTHINESS CERTIFICATE HAD BEEN REMOVED AND NOT REPLACED. CREW REQUIREMENTS ARE TO ENSURE REQUIRED MANUALS; MEL AND ACFT LOGBOOK ARE CONTAINED ON THE ACFT. CREW MUST CERTIFY THAT NO 'OPEN WRITE-UPS' ARE IN THE LOGBOOK AND THE LOGBOOK CONTAINS AN AIRWORTHINESS RELEASE SIGNATURE. THESE REQUIREMENTS WERE MET; ACCORDING TO COMPANY OPERATING MANUALS. MAINT PROCS DICTATE THAT PRIOR TO SIGNING THE AIRWORTHINESS RELEASE; THE ACFT IS IN AN AIRWORTHY CONDITION AND ACFT REGISTRATION. AIRWORTHINESS CERTIFICATE AND FEE PERMIT ARE ON THE ACFT. THESE REQUIREMENTS WERE NOT MET; ACCORDING TO COMPANY MAINT OPERATING MANUALS. CREW UNKNOWINGLY OPERATED THE ACFT WITHOUT THE AIRWORTHINESS CERTIFICATE INSTALLED. MAINT NEEDS TO FOLLOW ESTABLISHED QUALITY CTL STANDARDS; OR REVISE THEIR PROCS TO ELIMINATE OMISSION OF CRITICAL STEPS.