INCORRECT WAYPOINT ENTRY CAUSES GROSS NAV ERROR OVER NORTH PACIFIC.

Narrative

5 MINS BEFORE ENG START ATC INFORMED US THAT IT WOULD BE MORE THAN A 1 HR DELAY TO RECEIVE CLRNC ON OUR PLANNED RTE A590 FROM NRT TO ANC. ATC OFFERED NO DELAY ON R580. WE ACCEPTED AND RELOADED THE PMS WITH THE FIRST 8 WAYPOINTS ON R580 USING STANDARD COMPANY PROCS EXCEPT FOR DISTANCE CHKS DUE TO THE TIME CONSUMING EFFORT NECESSARY UTILIZING THE NORTH PACIFIC CHART. AFTER REACHING FL300 CRUISING ALT THE REMAINING WAYPOINTS TO ANC WERE ENTERED AGAIN USING STANDARD TECHNIQUES OF PNF READING LATITUDE/LONGITUDE FROM THE CHART AND PF TYPING INTO PMS AND SUBSEQUENTLY RECHKING ON THE #3 INS WITH PNF READING FROM CHART AND PF NOTING INS READOUT. TIME DISTANCE ESTIMATES WERE TRACKED USING #3 INS FOR ENSUING POS RPTS. A MISTAKE WAS MADE ENTERING THE LATITUDE/LONGITUDE FOR OFORD INTXN USING E DEGS INSTEAD OF W DEGS. AFTER ONEIL INTXN THE ACFT DIVERGED FROM CLRED TRACK. APCHING OGGOE INTXN ATC INFORMED THE FLT THAT IT WAS 20 NM N OF COURSE AND CORRECTING. AFTER SOME INVESTIGATION THE FLC DISCOVERED THE ERROR AND WAS GIVEN DIRECT TO AMOTT INTXN. MANY FACTORS ENTERED INTO THIS INEXCUSABLE EXCURSION; HOWEVER; PROBABLY A SIGNIFICANT AID WOULD BE BLANK OR GENERIC FLT PLAN FORMS MAKING IT LESS CONFUSING; REWRITING AND XING OUT THE PREVIOUS WAYPOINTS.