THE AIRPLANE FLOWN IS DIFFERENT FROM THE ONE DISPATCHED.

Narrative

I ARRIVED BY CREW VAN TO SJU ARPT WITH MY CREW. WE PROCEEDED THROUGH SECURITY AND TO OUR GATE; A FLT TO EWR. THE FLT WAS CORRECTLY MARKED AT THE GATE AND WAS THE ONLY ACFT AT ANY OF THE COMPANY GATES. AFTER THE CREW BOARDED THE ACFT; I REVIEWED THE ACFT AND CABIN LOGS AND REVIEWED THE PAPERWORK WHICH SJU OPS HAD DELIVERED TO THE ACFT. EVERYTHING APPEARED IN ORDER AND I SIGNED THE RELEASE AND ADVISED THE OPS REPRESENTATIVE ON BOARD THAT THE FUEL LOAD WAS OK -- FUELING COMMENCED. I THEN PROCEEDED TO THE COCKPIT TO CHK FLUID LEVELS AND SET UP FOR MY PREFLT. WE WERE LOW ON OIL SO I TOLD THE FO TO CALL OPS FOR MAINT TO ADD OIL. I ALSO TOLD HIM I WOULD PERSONALLY REMIND OPS AFTER I FINISHED THE WALKAROUND. THE OIL WAS ADDED AND NOTED IN THE ACFT LOG. THE REST OF THE FLT TO EWR WAS NORMAL. AFTER ARRIVING HOME FROM THE ARPT THAT DAY; I WAS CONTACTED BY THE CHIEF PLT'S OFFICE AND TOLD THAT I FLEW THE WRONG ACFT TO EWR. THE ACFT I SHOULD HAVE TAKEN WAS XXX INSTEAD OF YYY. THE CHIEF PLT ASKED IF I SAVED THE PAPERWORK OR REMEMBERED WHAT ACFT I SIGNED FOR ON THE DISPATCH RELEASE. I TOLD HIM I HONESTLY DID NOT REMEMBER; BUT WOULD REVIEW THE PAPERWORK THE NEXT DAY WHEN I RETURNED TO SJU. ACCORDING TO CHIEF PLT; THE CATERERS IN EWR DISCOVERED IT WAS THE WRONG ACFT AND RPTED IT TO SYS CTL. ON OCT/MON/00 I REVIEWED THE PAPERWORK IN SJU AND I HAD SIGNED FOR ACFT XXX VICE YYY. I THEN VISITED WITH THE STATION MGR AND REVIEWED THE PREVIOUS DAY'S EVENTS. HE SAID THERE HAD RECENTLY BEEN A SCHEDULE CHANGE WHICH SWITCHED THE LAST ACFT THAT ARRIVES IN SJU ON SATURDAYS TO LEAVE THE NEXT DAY TO IAH VICE DEPARTING TO EWR. THIS CHANGE PROBABLY TRIGGERED THE CHAIN OF EVENTS LEADING TO THE WRONG ACFT AT THE GATE THE MORNING WE DEPARTED FOR EWR. IN THE COCKPIT; THE ONLY PROB WE ENCOUNTERED WAS THE FMC WAS TRYING TO UPLOAD THE FLT TO IAH INSTEAD OF TO EWR WHICH THE FO MANUALLY OVERRODE. I HAVE HAD PROBS BEFORE UPLOADING FLTS FROM THE ISLANDS. WE WERE ALSO HAVING TROUBLE WITH OUR PRINTER; BUT THOUGHT IT WAS RELATED TO THE FMC UPLOAD PROB. I CANNOT HONESTLY REMEMBER IF I CHKED THE ACFT NUMBER DURING MY COCKPIT CHKS OR DURING THE REVIEW OF THE ACCULOAD; BUT I DO KNOW THAT THE FLT WAS OPERATED SAFELY FROM SJU TO EWR. RECOMMENDATION: I WILL ALWAYS VERIFY THE ACFT NUMBER WITH THE DISPATCH RELEASE; ACFT LOGBOOK AND DURING THE REVIEW OF THE ACCULOAD. SUPPLEMENTAL INFO FROM ACN 488080: IN MY OPINION; THIS ERROR WOULD HAVE BEEN CAUGHT IF THE FLC; DISPATCH; AND THE OPS MGR IN SJU HAD BEEN MORE VIGILANT IN DOUBLECHKING THE PAPERWORK FOR THE FLT AND MATCHING THAT WITH THE ACTUAL ACFT NUMBER FLOWN.