Date: 201505
Local time of day: 1201-1800
Location: ZDC.ARTCC, VA
Flight conditions: VMC
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B DCA
ATC / advisory: Center ZDC
Aircraft component: FMS/FMC
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Human-Machine Interface; Workload; Confusion; Communication Breakdown; Distraction
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Chart Or Publication; Human Factors; Procedure
Primary problem: Human Factors

Narrative: During preflight we received our ATC clearance for our DCA departure with a revised segment that included the addition of waypoint DIXXE. Reading the clearance I saw and typed into the FMS DIXIE. We completed the route check and then turned our attention to the tailwind on RWY 01 that required 2 new performance documents to be legal for takeoff (T/O). After spending time getting that straight and talking with the gate agent and the #1 as we were getting closed up; we called for push and were given instructions for a new runway and departure. That fixed the tailwind problem and so we made all the appropriate changes and pushed off the gate. Once airborne off of RWY 19; we contacted departure and were given direct 'Dixie' climb to 8000 feet; and; I recall; a frequency change. As the First Officer (FO) selected direct DIXIE on the FMS; I was hand flying using the HUD; and looked cross cockpit to see DIXIE on my FO's PLAN Mode on her Nav Display and said 'That looks good to me.' As we started our turn; my FO was surprised to see it was almost a 120 degree turn to the NE. After checking in with the new controller we were given direct to the waypoint after DIXIE; which was the next sequence waypoint in the FMS. The controller asked if were had been proceeding to the correct 'Dixie'. Not what you want to hear. Controller said there were two 'Dixie's'; one with 2 X's and one spelled with only one X. Grabbing the PDC we discovered that our 'Dixie' was indeed DIXXE not DIXIE which we had loading into the FMS on the ground. Controller informed us that it has been a problem with other flights and made a note of our error for their records. I asked if we had flown through any restricted airspace and Controller told us we had not. Once we were no longer sterile we begin to try to find how we had made this error and didn't catch it. Here are the main points that I recall and we found the reason for our error.1 - I didn't notice the different spelling and then put it in the FMS wrong. 2 - When we checked the route and I read from the box to paper; the FO didn't notice the different spelling either on the PDC as I read the route.3 - So everything appeared normal. Once we were happy with the correct revised segment and the entire route was correct in the FMS; we set off to fix the tailwind T/O issue.4 - We failed to do the legs check.  I cannot recall what stopped me from immediately doing the legs check; like I have done 1000 times before; after I read the route; but I didn't do it. If I had; we would have noticed about a huge NM difference between the FMS distance and the flight plan. We would have figured out something bad was wrong and found it and fixed it right then. So when we got direct to 'Dixie' from departure control; off we went to DIXIE and not DIXXE. It turns out that these two points are 156 NM away from each other. We didn't even get a USING RSV FUEL FMS message after putting it in the FMS incorrectly. That's how close they are geographically. Although it was a left turn of some large degree; since I haven't flown out of DCA in over 10 years and getting sent to a waypoint that wasn't south of DCA didn't seem terribly odd to me. My past recollection of flying out of DCA was that you never got to go where you wanted to on climb out. I just thought it was a nice good left turn. Using the HUD; I wasn't looking at where the pink line was headed; I was just flying the circle on the ball. My FO was very puzzled that it was more that a 30 degree turn or so; and was just about to ask for a clarification when we got direct to the next waypoint. Staying on task and completing prefight checks; even when there are distractions; is a must; and would have corrected this error. Also; maybe if I quit saying waypoints and just spell them phonetically if there is a manual entry change might help as well. That being said; having these two waypoints in such close proximity; one with just ONE letter different in their spelling is going to continue to cause issues. One of these waypoints needs to be renamed yesterday.


Second narrative: At the gate in DCA; we got a revised PDC; - DCT DIXXE COLIN.... We entered DIXIE instead of DIXXE in the Route Page. Neither of us caught the typo. We verified the route; but with several Performance/Runway Change FMC distractions; we didn't verify the waypoints on the Legs page; which would have trapped the error.After takeoff we were cleared direct DIXXE; however we had DIXIE in our route and turned too far to the left. While in the turn; ATC questioned the waypoint we were heading to and the error was discovered. No airspace was violated but the controller said they were collecting data; as this same error has happened in the past.Don't let distractions consume you from finishing a task (Legs check). The ATC Controller indicated there is a history of this particular waypoint error (typo). Perhaps one of the waypoint names should be changed. On time performance pressures from air carriers and the FAA's statistical rating system in itself; creates haste with the potential for errors; especially when dealing with late arriving aircraft and other such delays.


Synopsis: An air carrier crew with DIXXE in the PDC programmed the FMC with DIXIE and did not catch the error during route verification. After takeoff; when cleared direct DIXXE the aircraft turned northeast towards DIXIE instead of southwest and ATC caught the error.