An aircraft swap prior to departure results in the Dispatcher using a different route on the new release but not filing a new flight plan.
Synopsis
An aircraft swap prior to departure results in the Dispatcher using a different route on the new release but not filing a new flight plan.
Narrative
The original aircraft for the flight had a maintenance issue that required us to swap aircraft. We never looked at the original aircraft dispatch release. Upon receiving clearance we were given 'Cleared to ZZZ via radar vectors; DQN; CVG; IIU then as filed'. Our flight plan that we had on the paperwork was DQN; CVG; PXV; TIIDE; LIT; J180; .... When the FO picked up the clearance I was listening and programmed the FMS; he verified it. Once airborne we were cleared direct to PXV; the controller then changed it to direct IIU and said PXV was not on our flight plan. We then queried him; and got clarification on the actual route that they showed for us. He explained; DQN; CVG; IIU; J39; BNA; JAN; AEX; ... We then entered the correct flight plan in the FMS; then contacted Dispatch to verify that we would have enough fuel to take that route (and we did). After I got fuel burn from Dispatch I asked him what could have gone wrong. He explained that he did not refile the flight plan after the plane swap. We continued the flight; were asked to contact Indy Center upon landing. I contacted them and Dispatch to clarify. There were two main issues here. When we were given the clearance we simply added IIU after CVG. We both failed to realize that IIU was not on the original route. We simply added IIU in between the two fixes we originally had. If we had not done this we would have discovered the next issue. The second issue was the fact that after a change in planes the Dispatcher put a different route on the paperwork than what he had filed with ATC. This brings up obvious issues. Even though all of this occurred we never flew off course; we just had a communication issue; and the issue was resolved with no incident.
Second reporter narrative
During the preflight we encountered a maintenance discrepancy that required a plane swap to a new aircraft. After moving to the next aircraft we began getting ready for the flight. At this point I called Clearance to get our clearance for the flight. The controller gave the clearance as; 'Cleared to ZZZ via Radar Vectors to DQN; Direct CVG; Direct IIU; As Filed; Initial Climb to 5 Thousand; Expect Flight Level 360 in ten. Departure frequency XXX.XX and Squawk XXXX.' I then read back the Clearance and the Controller responded with 'Read back Correct.' While I was reading back the clearance the Captain was putting the flight plan into the FMS. When he was finished I verified what he had put in then FMS and then continued on with the rest of my duties. From there the flight continued normally until we were in the climb out of Columbus. At that point we were on the departure heading given by Columbus Departure. The Indianapolis Center Controller cleared us direct to PXV and then corrected himself saying that was not on our flight plan and cleared us to IIU. The Captain responded that it was on our flight plan; but the Center Controller disagreed and then continued to read us a new clearance; one different than what was on our flight plan. The Captain put that into the FMS and then called our Dispatcher to confer with him about where the differences came from in the filed flight plan. We continued thinking no problem was caused until about an hour later when a new Center Controller gave us a phone number for Indy Center to call when we landed. The Captain called the number and explained the confusion was due to our Dispatcher filing two different routes; one for each of the aircraft we were supposed to fly and that the clearance we got from Clearance Delivery was different from the one that we had on our release. We didn't notice the difference because the clearance was read back with 'As filed' which did not include the clearance as we had on our flight plan. We did not notice that IIU was not included in our originally filed flight plan and should have picked up on the difference.A suggestion to fix this issue is to find a way to not allow a flight plan to be filed with ATC with 2 different tail numbers and 2 different routes unless the flight number for the flight is changed in some way. There shouldn't be a way for a specific flight number to have 2 different routes; and 2 different tail numbers.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.