EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors; Procedure
After checking-in with Washington Center (it was either Washington or Potomac) we were hearing of many deviations on the PHLBO arrival into EWR due to building storms along the arrival. After a few minutes of being on frequency we were given instructions to fly direct to the BESSE intersection; then direct a fix north of DQO; I believe it was DYLIN. As the controller was issuing the instruction; he spelled the intersection. As he did; I typed it into the FMS scratch pad and confirmed with the Captain that it was the correct fix. He wrote the intersection down as the instruction was issued; and we both agreed it was correct. The BESSE fix took us further west than our original flight plan; but seemed to keep us clear of the weather so we did not question it. We were handed off to; and checked in with Potomac and heard nothing after the check-in for probably ten minutes or so. The controller then asked which fix we were going to; and seemed confused as to why we were going that direction for BESSE. After having us spell the fix; controller discovered that we were going to another BESSE; and that we should have been going to BESSI; much further north. Controller issued us a heading to get on course while we programmed the FMS; and explained no being aware of the existence of a BESSE intersection. After getting on course we were handed off to the next sector and thanked for our help. The flight continued without further issue or complication. In this case the two fixes were spelled the same with the exception of one letter. I believe the Captain did read back the spelling of the fix; so it is hard to tell if the error was detectable. Being that the two fixes were relatively close together (BESSE and BESSI are both in the northeast) it did not trigger a mental flag to question the assignment. In other cases of duplicate fixes; one fix may be on a totally different continent and the FMS will prompt the crew accordingly; but this not being the case made the threat more prominent.
EMB145 First Officer reported a track deviation after being cleared direct to BESSI during arrival to EWR. The crew entered BESSE into the FMC and ATC detected the error.