Narrative:

During preflight preparation, captain had to manually enter overwater flight coordinates. For the coordinate at 150W, he correctly labeled the waypoint 36N 150W and the coordinates 36.00.0 north, 150.00.0 west into the navigation data base. First officer was asked to string the flight plan which he did using the labeled coordinates from the flight plan. On xchk of computer load against paper computer flight plan/release, 150W coordinate missing. This was signal to crew that something was wrong. In looking at the W150 waypoint in the body of the flight plan, found coordinates for N36, W150 but labeled N38. Computer error in generation of label for waypoint. Potential fatal consequences as flight was filed via 38N but would have flown to 36N, miles off course. Whole chain of safety checks did not work. Computer self-check analysis program failure, failure of flight dispatch to see/correct error. Had crew not meticulously followed company procedures they would not have caught error. This incident has been reported to flight management (flight manager, and flight safety department) and they can be contacted to ascertain how the safety chain broke so bad in this case. They will conduct further investigation. Flight plan and ACARS message attached. Callback conversation with reporter revealed the following information: the computer generated flight plan planned an unusual flight track and varied from the cleared route. It was likely due to current winds associated with the jet stream -- the computer selects a routing (assuming it's a random track vice a north pacific airway) depending on the winds and most efficient routing and altitude. In this case, the winds at 160W were 310 degrees at 120 KTS, a major wind shift occurred by 150W, dropping to 36 KTS. That, in conjunction with an altitude change, coincided with the latitude variation. Flight plan routing showed 38N 150W as next reporting points at both 170W and 160W, but then 36N 150W at the reporting point. Also, the clearance showed 38N 150W. Flight crew saw the discrepancy during the cockpit setup, left it as it was and refiled in the air while en route. Reporter has had no feedback from his company, but he has filed reports with them and expects to hear back. For some reason this particular flight plan was sent and the ensuing communication was difficult, whereas, had the plan come from narita it would have simplified communication.

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Original NASA ASRS Text

Title: ANOMALY IN LATITUDES ON TRANSPACIFIC FLT PLAN CLRNC. ONE SHOWS 150W AT 36N AND ONE SHOWS 150W AT 38N. PROBABLE WIND SHIFT AND ALT CHANGE CONTRIBUTED TO THE ANOMALY.

Narrative: DURING PREFLT PREPARATION, CAPT HAD TO MANUALLY ENTER OVERWATER FLT COORDINATES. FOR THE COORDINATE AT 150W, HE CORRECTLY LABELED THE WAYPOINT 36N 150W AND THE COORDINATES 36.00.0 N, 150.00.0 W INTO THE NAV DATA BASE. FO WAS ASKED TO STRING THE FLT PLAN WHICH HE DID USING THE LABELED COORDINATES FROM THE FLT PLAN. ON XCHK OF COMPUTER LOAD AGAINST PAPER COMPUTER FLT PLAN/RELEASE, 150W COORDINATE MISSING. THIS WAS SIGNAL TO CREW THAT SOMETHING WAS WRONG. IN LOOKING AT THE W150 WAYPOINT IN THE BODY OF THE FLT PLAN, FOUND COORDINATES FOR N36, W150 BUT LABELED N38. COMPUTER ERROR IN GENERATION OF LABEL FOR WAYPOINT. POTENTIAL FATAL CONSEQUENCES AS FLT WAS FILED VIA 38N BUT WOULD HAVE FLOWN TO 36N, MILES OFF COURSE. WHOLE CHAIN OF SAFETY CHKS DID NOT WORK. COMPUTER SELF-CHK ANALYSIS PROGRAM FAILURE, FAILURE OF FLT DISPATCH TO SEE/CORRECT ERROR. HAD CREW NOT METICULOUSLY FOLLOWED COMPANY PROCS THEY WOULD NOT HAVE CAUGHT ERROR. THIS INCIDENT HAS BEEN RPTED TO FLT MGMNT (FLT MGR, AND FLT SAFETY DEPT) AND THEY CAN BE CONTACTED TO ASCERTAIN HOW THE SAFETY CHAIN BROKE SO BAD IN THIS CASE. THEY WILL CONDUCT FURTHER INVESTIGATION. FLT PLAN AND ACARS MESSAGE ATTACHED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE COMPUTER GENERATED FLT PLAN PLANNED AN UNUSUAL FLT TRACK AND VARIED FROM THE CLRED RTE. IT WAS LIKELY DUE TO CURRENT WINDS ASSOCIATED WITH THE JET STREAM -- THE COMPUTER SELECTS A ROUTING (ASSUMING IT'S A RANDOM TRACK VICE A NORTH PACIFIC AIRWAY) DEPENDING ON THE WINDS AND MOST EFFICIENT ROUTING AND ALT. IN THIS CASE, THE WINDS AT 160W WERE 310 DEGS AT 120 KTS, A MAJOR WIND SHIFT OCCURRED BY 150W, DROPPING TO 36 KTS. THAT, IN CONJUNCTION WITH AN ALT CHANGE, COINCIDED WITH THE LATITUDE VARIATION. FLT PLAN ROUTING SHOWED 38N 150W AS NEXT RPTING POINTS AT BOTH 170W AND 160W, BUT THEN 36N 150W AT THE RPTING POINT. ALSO, THE CLRNC SHOWED 38N 150W. FLC SAW THE DISCREPANCY DURING THE COCKPIT SETUP, LEFT IT AS IT WAS AND REFILED IN THE AIR WHILE ENRTE. RPTR HAS HAD NO FEEDBACK FROM HIS COMPANY, BUT HE HAS FILED RPTS WITH THEM AND EXPECTS TO HEAR BACK. FOR SOME REASON THIS PARTICULAR FLT PLAN WAS SENT AND THE ENSUING COM WAS DIFFICULT, WHEREAS, HAD THE PLAN COME FROM NARITA IT WOULD HAVE SIMPLIFIED COM.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.