B737-800
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 261
Confusion; Human-Machine Interface
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Company Policy; Human Factors
We met the aircraft early on the first leg of the last day of the pairing. There was plenty of time to complete our duties. While the First Officer was conducting the exterior inspection; I (Captain) began to program the FMC for the flight from BOS. The route was a non-standard route and I programmed the route according to procedure. The First Officer returned to the flight deck shortly thereafter and we completed the rest of our preflight duties; briefings; and checklists. The taxi out and initial climb were uneventful. At FL230 and passing HYLND intersection; we requested a right (north) deviation around weather. The controller informed us that our route should have kept us north of the weather. He said we appeared to be heading direct METRO intersection instead of MERTO intersection. MERTO was indeed on our flight plan but METRO was programmed into the FMC. I had transposed the spelling and put the wrong intersection into the FMC during preflight. The controller cleared us direct MERTO intersection and flight plan route. He was very professional regarding the matter and alluded to the fact this had happened to other aircraft. We were fortunate we had just made the turn and the navigational error was minimal and caused no disruption in air traffic flow.I was the one who programmed the FMC. It was/is my responsibility to ensure the flight plan is properly input. As a crew; we should have caught the error. Both of us overlooked the spelling of the intersection in this event. We were not rushed and conducted briefings according to company procedure. I will be more vigilant in ensuring the route is properly programmed into the FMC; paying close attention to those intersections with similar spellings. I will also continue to encourage my co-workers to check my work and review the flight plan programmed into the FMC--regardless of who made the inputs.
B737-800 Captain experienced a track deviation as a result of miss programing the FMC with METRO instead of MERTO. The two waypoints are several hundred miles apart and not in line.