A B757-200 FLC DEVIATES FROM THEIR FILED FLT PLAN BELIEVING THAT THEIR REQUESTED ROUTING THROUGH DISPATCH HAD BEEN FILED AND THE OLD ONE CANCELED WHILE IN CRUISE FLT NE OF LAS; NV.

Narrative

CAPT CALLED THE DISPATCHER TO DISCUSS ROUTING LAS TO BOS. CAPT AND DISPATCHER AGREED ON A DIFFERENT RTE TO FLY. DISPATCHER ISSUED NEW FLT PLAN WITH NEW ROUTING; BUT DID NOT FILE NEW RTE WITH ATC. FLT DEPARTED LAX AND IN ZOA ATC AREA STARTED FLYING THE SECOND RTE WHICH WAS DISCUSSED WITH DISPATCHER. ATC CTLR WAS EXPECTING FIRST RTE. CTR CTLR NOTIFIED DISPATCHER AND CAPT NOTIFIED DISPATCHER AND MISUNDERSTANDING WAS CLRED UP WITH ALL PARTIES INVOLVED. THE INITIAL ROUTING WAS A ROUTING REQUESTED BY ATC FOR THE LAX-BOS CITY PAIR TO BE FLOWN. THIS RTE WAS BEING AFFECTED BY WX SO THAT IS THE REASON FOR THE RTE CHANGE. DISPATCHER'S WORKLOAD WAS HIGH DUE TO DISPATCHING TRANSCONTINENTAL FLTS. ATC WAS ISSUING PLAYBOOK ROUTINGS ALONG WITH PLAYBOOK ROUTINGS WITH AMENDMENTS WHICH THE DISPATCHER HAD TO VERIFY EACH ROUTING FOR EACH FLT WITH THE ROUTING REQUESTED BY ATC TO FILE. THIS SECOND ROUTING FOR THIS LAX-BOS FLT WAS NOT REFILED AND THE INITIAL FLT PLAN WAS NOT CANCELED. THE PLT DID NOT NOTICE THE DIFFERENCE BTWN THE CLRNC AND THE FLT PLAN ISSUED TO HIM.