AN ACR B767 FLC DISCOVERED THAT THE FLT ROUTING IN THEIR FMC WAS DIFFERENT FROM THE ROUTING THAT ATC EXPECTED AND THEIR DISPATCHER FILED. THE PROB WAS RESOLVED BEFORE A DEV OCCURRED; HOWEVER THE CAUSE IS STILL BEING INVESTIGATED BY THEIR COMPANY'S DISPATCH DEPT.

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RELEASE #2 CALLED FOR THE FLT PATH AFTER PASSING LIN TO PROCEED VIA J84 MVA; J198 ILC; J80 JNC; ETC. SHORTLY BEFORE FLT ARRIVED OVER ILC; THE ATC CTLR CLRED US WITHOUT CREW REQUEST TO 'PROCEED TO DIRECT TO HBU; ON COURSE.' ON REFERRING TO THE FMC LOADED FLT PLAN; THE ATC CLRNC AND THE HIGH ALT NAV MAP (H 1/2); THE CREW RESPONDED TO THE ATC CTLR THAT HBU WAS NOT ON THE FILED FLT PLAN RTE. THE ATC CTLR THEN RESPONDED 'WELL; I DO SHOW IT ON THE RTE. LET'S TRY THIS: YOU ARE CLRED DIRECT HBU; J146.' THE CREW ATTEMPTED A RTE MODIFICATION TO THE FLT PLAN WHICH HAD BEEN ORIGINALLY LOADED INTO THE FMC. IT WAS IMMEDIATELY NOTED THAT THERE EXISTED A RTE DISCONTINUITY AFTER PASSING HBU. BY THEN; WE HAD BEEN SWITCHED TO ANOTHER ATC CTLR FREQ. THE CREW REQUESTED THAT ATC BE MADE AWARE THAT THE CREW WAS CONFUSED AS TO WHAT THE LAST ATC CTLR HAD ACTUALLY WANTED US TO DO. THE CTLR STATED THAT FLC WAS TO PROCEED; AFTER PASSING HBU; ON J146. CREW THEN TOLD ATC THAT THE FLT PLAN COUPLED WITH THAT CLRNC WOULD RESULT IN A RTE DISCONTINUITY IN THAT THESE WERE 2 DIFFERENT RTES. FURTHER DISCUSSION RESULTED IN THE DISCOVERY THAT THE FLT PLAN RTE LOADED INTO THE FMC WAS IN FACT TOTALLY DIFFERENT THAN THE ATC COMPUTER FLT PLAN FILED BY OUR DISPATCH. THE RTE DIVERGENCE BEGAN AT MLF. EVENTUALLY; OUR FLT WAS RECLRED BY ATC TO PROCEED ON COURSE VIA THE COURSE WHICH HAD BEEN ORIGINALLY LOADED INTO THE FMC BY THE CREW IN REF TO RELEASE #2. CREW THEN BECAME FURTHER CONCERNED THAT OUR DISPATCH SHOULD KNOW ABOUT THIS CONFUSION. VIA ACARS; CONTACT WAS ESTABLISHED WITH THE DISPATCHER WHO HAD ORIGINALLY FILED THE FLT PLAN FOR US. DURING NEARLY 30 MINS OF CONVERSATION; IT WAS DISCOVERED THAT THE FLT PLAN IN THE COMPANY'S COMPUTER WAS THE SAME AS THE FLT PLAN IN THE ATC COMPUTER. THUS; THIS WAS A FLT PLAN RTE WHICH WAS DECIDEDLY DIFFERENT FROM THE ONE APPEARING ON RELEASE #2! THE DISPATCHER REVEALED TO THE CREW THAT RELEASE #1 HAD BEEN OFFICIALLY CANCELED WITH ATC; THAT A NEW FLT PLAN RTE FILED WITH AND APPROVED BY ATC; AND AFTER THAT A NEW RELEASE; RELEASE #2; HAD BEEN GENERATED AND SENT TO SFO FLT OPS. FOR SOME ABSOLUTELY UNKNOWN REASON; THE CANCELED FLT PLAN RTE APPEARING ON RELEASE #1 ALSO APPEARED ON RELEASE #2; BUT NOT IN THE COMPANY COMPUTER; NOR IN THE ATC COMPUTER. THE PROGRAM USED FOR CANCELLATION WAS REFERRED TO BY THE DISPATCHER AS 'XXXXX' AND IS A FUNCTION OF OUR COMPANY'S COMPUTER SYS. SOMEHOW XXXXX HAD CANCELED THE RELEASE #1 FLT PLAN RTE IN BOTH THE COMPANY'S AND THE ATC COMPUTERS; BUT IT HAD ALLOWED RELEASE #2 TO BE GENERATED WITH THE SAME FLT PLAN RTE WHICH APPEARED TO THE DISPATCHER TO HAVE BEEN CANCELED! THE CREW COULD NOT HAVE KNOWN THIS; FOR IT WAS NEVER AFFORDED THE OPPORTUNITY TO COMPARE RELEASE #1 WITH RELEASE #2 TO OBSERVE THE DIFFERENCES IN THE 2 RTES. IN SUMMARY; AT THIS POINT; OUR DISPATCH DOES NOT HAVE AN ANSWER AS TO WHAT MAY HAVE HAPPENED; NOR HOW THE PROGRAM ALLOWED THIS ERROR TO OCCUR. FURTHER; NO EXCURSION FROM THE FILED RTE EVER TOOK PLACE. HOWEVER; HAD THERE BEEN NO UNSOLICITED ATC CLRNC TO PROCEED DIRECT TO HBU; OUR FLT WOULD IN FACT HAVE DEVIATED FROM THE FILED RTE IMMEDIATELY AFTER PASSING MLF ON J80! IT WOULD HAVE PROCEEDED DOWN TRACK ON J80 TOWARD JNC VICE J28 TOWARD HVE AND HBU (IF THAT WAS THE RTE FILED; FOR THE CREW TO THIS POINT IN TIME DOES NOT HAVE KNOWLEDGE OF EXACTLY WHICH RTE WAS FILED; AND WHICH WAS INTENDED TO HAVE BEEN REFLECTED ON RELEASE #2). RELEASE #2 DOES IN FACT CONTAIN WITHIN ITS BODY A PREVIOUSLY CANCELED FLT PLAN RTE; ONE THAT HAD BEEN CANCELED BY BOTH OUR DISPATCH AND BY ATC. FURTHER; DISPATCH AND ATC HAD APPROVED AND ISSUED A NEW FLT PLAN RTE. RELEASE #2 DOES NOT REFLECT THAT CHANGE. THERE EXISTS; THEREFORE; BY THIS EXAMPLE; AN OPPORTUNITY FOR A FLC TO FLT PLAN; APPROVE; LOAD INTO THE AIRPLANE FLT COMPUTER; RECEIVE FOR ALL PRACTICAL PURPOSES ALL POSSIBLE CONFIRMATION AS TO ITS CURRENCY AND VALIDITY; AND THEM ATTEMPT TO FLY A COMPLETELY INVALID FLT PLAN. THE RAMIFICATIONS OF SUCH AN EVENT; GIVEN MORE URGENT CIRCUMSTANCES; COULD BE VERY UNFAVORABLE. IT APPEARS THAT THERE IS NO VALIDATION CHK IN PLACE WHICH ASSURES A DISPATCHER THAT; WHEN A FLT PLAN RTE CHANGE IS MADE; THAT THE CREW ACTUALLY RECEIVES THAT CHANGE. IT ONLY VALIDATES THAT THE CREW IS AWARE THAT THE SEQUENTIAL NUMBER OF THE CURRENT RELEASE HAS BEEN RECEIVED. IT SEEMS THAT THE XMISSION OF NOMENCLATURE SUCH AS RELEASE #1 OR RELEASE #2 IS NOT ENOUGH TO INSURE THAT THE CREW HAS IN HAND THE PROPER FLT PLAN RTE WHEN RTE CHANGES HAVE BEEN MADE; REGARDLESS OF THE TIME LINE.