Date: 201505
Local time of day: 1801-2400
Location: ZBW.ARTCC, NH
Flight conditions: IMC
Aircraft: A320
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Cruise
Airspace: Class A ZBW
ATC / advisory: Center ZBW
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Communication Breakdown
Second reporter function: Captain; Pilot Not Flying
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Equipment / Tooling; Human Factors; Procedure
Primary problem: Ambiguous

Narrative: Just past the waypoint GONZZ; ATC asked where we were going. Replying our next fix as HANKK ATC stated that wasn't the routing they had. We read off our routing which was nothing the controller had us filed with. At this point ATC gave us a new routing which we flew and stated they had no issue; no problem. We checked our ACARS Release Verify which stated we were still RLS1. After speaking with Dispatch; he stated that there was a re-route right around our departure; that he re-ran the flight plan; released it and Sabre re-filed but DIDN'T re-release. At this point I figured the issue was either with BOS clearance or our computer system. Then I remembered something had caught my attention about the PDC during preflight. Looking back at the PDC it listed our filed route as the HYLND3.HYLND CAM ...; which RLS1 stated but the Clearance Revision stated HYLND3.HYLND SYR .... What I did immediately after noting that I cannot remember; either last night trying to figure out what happened or today filling out this report. Perhaps I was interrupted... or the fact that many Clearance Revisions state the filed route through the flights first sector with no actual changes and basically adding noise to the preflight. I don't know.We were lucky this time but obviously an aircraft flying a route that's different from ATC is a giant issue. I realize as one of the links in the chain; had I queried about what do I do after SYR on the Revision; then I would have realize I didn't have the routing I was filed with.


Second narrative: As we were navigating on Q29 to HANKK intersection; the controller asked us where we were going; to which I responded; HANKK. He advised that HANKK was not on our route and asked us to verify our filed routing. He then cleared us to HOCKE; which was on the route ATC apparently had us filed on. We checked our papers and confirmed that we were on Release 1 and that the proper route had been loaded into the FMGCs. All looked good to us at that point so we confirmed this routing to the controller. The controller advised us otherwise; and proceeded to issue the remainder of the route we should have been on according to his information. I contacted Dispatch to see what was up and was advised that somewhere near our take off time that he had received a new ATC routing; had run a new plan; refilled us and cancelled the original release. Apparently Sabre did everything he had requested except for re-releasing our flight; which apparently it should have. He advised that he would follow up with a report.After getting on the same page as ATC; I proceeded to review all the documents that we had received and discovered that we had overlooked a small change in the Revised Segment of the PDC. Although the revised segment included our filed SID; (HYLND3.HYLND); I noted that direct to SYR from HYLND had been included. I initially thought the revised segment was a repeat of our cleared routing; which I believed included SYR. I did so based on prior experience with revised segments that were identical to our filed route but never actually contained anything different. Upon closer inspection; I realized I had missed an opportunity to identify a threat had I only inquired about SYR and discovered its significance to our flight. Although we should have investigated why SYR appeared in the revised segment it should be noted that none of the reroute ATC had given to our Dispatch other than SYR appeared there.


Synopsis: A320 flight crew experiences a track deviation when a revised segment on their PDC is overlooked; believing that no change actually exists. Complicating matters the Dispatch computer did not generate a release number two with the new routing and the PDC only contained one fix on the new routing.