Narrative:

Aircraft cleared FM 54 north 20 west to 55 north 10 west incorrect waypoints loaded into INS, 54 north 10 west was loaded, aircraft 30-35 mi right of course when second officer plotted mistake and we corrected back on course. Three crew members checked INS latitude and long loading and the error was not found. Three major mistakes. First error, first officer loaded first set of waypoints (1-9), captain and first officer used new fom procedures and all latitude and long and distances checked. (Captain read latitude and long off F/P, first officer checked INS). After second set was loaded by first officer, captain and first officer checked waypoints. Captain read and first officer checked coords from flight plan not INS. I mixed up the new fom procedures and the old fom procedures. Second mistake, both captain and first officer noticed mileage difference (flight plan to INS), checked latitude and long instead of 55 north which was correct (see attached flight plan). Both of us thought the 5 mi difference was a flight plan error (we had found previous errors). Third mistake. Second officer checked first set of latitude and longs but did not check second set on third INS. But second officer was doing plotting chart and saw our deviation at 15 west where we returned to on course. I was doing everything by the book, but I mixed up my books. 23 yrs, 15000 plus hours and many xings you can still make mistakes.

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Original NASA ASRS Text

Title: MLG TRACK HEADING DEVIATION ON ATLANTIC ROUTE. FLT CREW HAD ENTERED THE WRONG LAT IN THE INS.

Narrative: ACFT CLRED FM 54 N 20 W TO 55 N 10 W INCORRECT WAYPOINTS LOADED INTO INS, 54 N 10 W WAS LOADED, ACFT 30-35 MI R OF COURSE WHEN S/O PLOTTED MISTAKE AND WE CORRECTED BACK ON COURSE. THREE CREW MEMBERS CHKED INS LAT AND LONG LOADING AND THE ERROR WAS NOT FOUND. THREE MAJOR MISTAKES. FIRST ERROR, F/O LOADED FIRST SET OF WAYPOINTS (1-9), CAPT AND F/O USED NEW FOM PROCS AND ALL LAT AND LONG AND DISTANCES CHKED. (CAPT READ LAT AND LONG OFF F/P, F/O CHKED INS). AFTER SEC SET WAS LOADED BY F/O, CAPT AND F/O CHKED WAYPOINTS. CAPT READ AND F/O CHKED COORDS FROM FLT PLAN NOT INS. I MIXED UP THE NEW FOM PROCS AND THE OLD FOM PROCS. SEC MISTAKE, BOTH CAPT AND F/O NOTICED MILEAGE DIFFERENCE (FLT PLAN TO INS), CHKED LAT AND LONG INSTEAD OF 55 N WHICH WAS CORRECT (SEE ATTACHED FLT PLAN). BOTH OF US THOUGHT THE 5 MI DIFFERENCE WAS A FLT PLAN ERROR (WE HAD FOUND PREVIOUS ERRORS). THIRD MISTAKE. S/O CHKED FIRST SET OF LAT AND LONGS BUT DID NOT CHK SEC SET ON THIRD INS. BUT S/O WAS DOING PLOTTING CHART AND SAW OUR DEV AT 15 W WHERE WE RETURNED TO ON COURSE. I WAS DOING EVERYTHING BY THE BOOK, BUT I MIXED UP MY BOOKS. 23 YRS, 15000 PLUS HRS AND MANY XINGS YOU CAN STILL MAKE MISTAKES.

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.