A G IV Captain reported a track deviation at 180W during a trans Pacific flight to Oahu. The 180W coordinate was inadvertently omitted from the FMC flight plan. The aircraft flew direct from the 170E fix to the 170W fix and crossed 180W 19 NM north of the filed route.

Narrative

While flying a trans-Pacific crossing from Japan to Oahu; flight crossed 180W longitude 19 miles north of point filed on flight plan/cleared by ATC. After noting error; ATC re cleared flight back to filed route. Flight continued to destination without incident. Post flight analysis revealed cause of event to be pilot error. Flight was initially planned using commercial flight planning software. This program generates a route of flight and automatically incorporates into filed flight plan. Aircraft commander (who was training a new copilot) elected to demonstrate the use of military flight planning software utilizing the route of flight generated and filed by the commercial program by reentering the route into the military software. While copying the route of flight directly from the filed flight plan; pilot inadvertently omitted the point at 180W. As a result; when the military fuel plan was generated the route generated between 170E and 170W crossed 180W 19 minutes north of the filed plan. Normal pre-flight procedures were followed; with the route of flight entered directly from the fuel plan and points along the route verified by both pilots. Unfortunately; because the fuel plan and the flight plan had one point that differed; the document used to verify the route entered into the FMS did not match the filed flight plan. This was not noticed until after the point was reported to ATC and they questioned the error. During the flight plotting procedures were followed but the ten minute position plotted after 170E did not indicate enough of a deviation to be noticed by pilots (probably because of the distance between points and the fact that 19 minutes longitude did not produce much deviation from that distance). Lesson learned: if different products are used to plan and file a route of flight; FMS-entered route should be verified directly off the filed flight plan NOT the fuel plan. This ensures that the route ATC has matches the FMS.