FLT PLAN FILED OTHER THAN THE ONE RECEIVED FROM ATC. HDG TRACK POS DEV IN CLRNC INTERP INCIDENT. ACFT EQUIP PROB WITH ACR'S; NO PDC PROCS AVAILABLE.

Narrative

THE FO TRIED UNSUCCESSFULLY SEVERAL TIMES TO GET OUR CLRNC FROM PHL TO SFO VIA THE ACARS SYS. WE WERE BOTH SEATED IN THE COCKPIT AT THE TIME. I WAS DISCUSSING ANOTHER PROB WITH THE 'A' FLT ATTENDANT AND A MECH. THE FO THEN RECEIVED OUR CLRNC FROM PHL CLRNC DELIVERY VIA THE VHF RADIO. AFTER HE GOT THE CLRNC HE STATED THAT THE ROUTING WAS 'AS FILED' ON OUR FLT PLAN. IN FACT THE ROUTING HAD BEEN CHANGED. ORIGINALLY WE HAD REQUESTED AN INITIAL ROUTING FROM PHL DIRECT TO MXE THEN VIA MXE 278 TO PENSY J48 EMI V166 RUANE DIRECT MRB J6. THE CLRNC AS GIVEN WAS DIRECT MXE; THEN THE MXE 278 RADIAL TO J6. ALTHOUGH THESE ROUTINGS SEEM VERY SIMILAR THERE IS IN FACT A LARGE BI-PASSING OF THE PENSY EMI RUANE AREA. ONCE AIRBORNE AND HANDED OVER TO ZNY WE WERE TOLD TO FLY DIRECT TO 'FLIRT.' THE FO WAS FLYING THIS LEG AND I WAS DOING THE RADIO WORK. I TOLD THE CTR THAT 'FLIRT' WASN'T ON OUR RTE. WE WERE GIVEN A FREQ CHANGE AND THE NEXT CTLR GAVE US A HDG TO FLY. I ASKED FOR DIRECT MRB. HE SAID UNABLE. I ASKED THE FO AGAIN HOW WE WERE CLRED. HE PULLED OUT HIS COPY OF THE CLRNC. WE BOTH REALIZED THAT THE ROUTING HAD BEEN SUBTLY CHANGED. I IMMEDIATELY INFORMED CTR AND WE WERE CLRED TO INTERCEPT J6. WE WERE VFR AND NO CONFLICT WAS INVOLVED.