NON COMPLIANCE WITH MEL REQUIREMENTS.

Narrative

THE INBOUND CREW; THE EVENING BEFORE ENTERED INTO THE ACFT LOGBOOK; TCASII INOP. I ARRIVED THE NEXT MORNING TO WORK THE NEXT LEG. MISSOULA IS A NON-MAINT STATION FOR OUR OPS. I TELEPHONED MAINT COORDINATOR AND FLT CTL TO SEND ME A TELETYPE AUTHORIZATION FORM TO DEPART WITH THE INOP TCASII SYS; IN ACCORDANCE WITH SOPS. THE MEL STATED THAT THE SYS BE DEACTIVATED IN ACCORDANCE WITH MAINT PROCS. BEING MISSOULA IS A NON-MAINT STATION; I DECIDED TO LEAVE THE SYS OFF. BUT ON INITIAL PREFLT; THE TCASII SYS TESTED NORMAL IN ACCORDANCE WITH MANUFACTURER TEST PROCS. WE DEPARTED AND ON DEP; I DECIDED TO CHK THE SYS ENRTE TO GIVE THE NEXT MAINT STATION; DATA SHOWING THE SYS WORKING; SO THE WRITE UP COULD BE CLRED FROM THE LOGBOOK. ENRTE THE TCASII WORKED PERFECT. AN FAA MAINT INSPECTOR WAS RIDING JUMP SEAT; AND AFTER LNDG INFORMED ME THAT I HAD NOT COMPLIED WITH THE MEL; BECAUSE THE SYS WAS TO BE DEACTIVATED! AT BLOCK IN; MAINT PERFORMED A BITE TEST; AND THE TCASII WORKED PERFECT! CHAIN OF EVENTS: PROBLEM AROSE -- INBOUND FLC. CONTRIBUTING FACTORS: NON-MAINT STATION. HOW DISCOVERED: LOGBOOK OPEN WRITE UP. CORRECTIVE ACTIONS: AUTHORIZED MAINT RELEASE TELETYPE. HUMAN PERFORMANCE CONSIDERATIONS: JUDGEMENTS; DECISIONS -- SYS TESTED NORMAL ON PREFLT; DECIDED TO CHK ENRTE TO HELP NEXT MAINT STATION CLR WRITE UP. CORRECTIVE ACTIONS: PLT WILL COMPLY FULLY WITH MEL; EVEN IF 'OFF' SYS IS TESTING AND OPERATING NORMALLY.