Narrative:

We departed stansted england. My first officer was flying and I was handling the radios and navigation. We were climbing above 18000 ft to FL350 en route to lands end VOR. Since we were going to coast out soon, I told my first officer I would get the oceanic clearance and the flight engineer would back me up on the clearance and for him (first officer) to fly the aircraft and monitor london ATC. Our flight plan called for an oceanic crossing of 49n15w 49n20w 49n30w 49n50w yqy (gander), but the oceanic clearance was different to 49n15w 49n20w 49n30w 49n40w 48n50w yyt (torbay). On the master flight plan I crossed out yqy (gander) and wrote in yyt (torbay) and entered the coordinates into my INS. But I didn't cross out 49n50w to 48n50w, so I didn't change the coordinates in my INS. My first officer asked me what the clearance was and I told him cleared as filed except they changed yqy (gander) to yyt (torbay) so my first officer entered the coordinates into his INS. We compared coordinates and the routing between the 2 INS's. Since I didn't change the coordinates from 49n502 to 48n50w, the discrepancy wasn't found. I then filled out the airep form to make our position reports. I filled out the coordinates of the scratch pad where I had written down the ATC oceanic clearance where the correct coordinate of 48n50w was written down. All the way across the atlantic I checked the waypoint coordinates against the computerized flight plan. When I checked the waypoint 49n50w on the flight plan, it matched the INS. At about 10 NM from 49n50w, I saw on my scratch pad where I had written the oceanic clearance 48n50w direct yyt (torbay). Since we weren't in radar contact, I immediately informed gander center that we were proceeding direct 49n50w instead of 48n50w. Gander said proceed direct 48n50w squawk XXXX. I feel my biggest mistake was I should have written the oceanic clearance on the computer flight plan where I would have picked up the mistake of not crossing out the coordinates of 49n50w for 48n50w. Thinking back over this trip, nowhere during the oceanic crossing did my first officer pick up the computer flight plan or the airep form to check for any mistakes. I feel I am responsible for the navigation error. But, if my first officer had looked at the airep form, my mistake might have been found long before it would have become a navigation error.

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Original NASA ASRS Text

Title: A HVT ACR FREIGHTER ACFT HAD A GROSS NAV ERROR OVER THE ATLANTIC.

Narrative: WE DEPARTED STANSTED ENGLAND. MY FO WAS FLYING AND I WAS HANDLING THE RADIOS AND NAV. WE WERE CLBING ABOVE 18000 FT TO FL350 ENRTE TO LANDS END VOR. SINCE WE WERE GOING TO COAST OUT SOON, I TOLD MY FO I WOULD GET THE OCEANIC CLRNC AND THE FE WOULD BACK ME UP ON THE CLRNC AND FOR HIM (FO) TO FLY THE ACFT AND MONITOR LONDON ATC. OUR FLT PLAN CALLED FOR AN OCEANIC XING OF 49N15W 49N20W 49N30W 49N50W YQY (GANDER), BUT THE OCEANIC CLRNC WAS DIFFERENT TO 49N15W 49N20W 49N30W 49N40W 48N50W YYT (TORBAY). ON THE MASTER FLT PLAN I CROSSED OUT YQY (GANDER) AND WROTE IN YYT (TORBAY) AND ENTERED THE COORDINATES INTO MY INS. BUT I DIDN'T CROSS OUT 49N50W TO 48N50W, SO I DIDN'T CHANGE THE COORDINATES IN MY INS. MY FO ASKED ME WHAT THE CLRNC WAS AND I TOLD HIM CLRED AS FILED EXCEPT THEY CHANGED YQY (GANDER) TO YYT (TORBAY) SO MY FO ENTERED THE COORDINATES INTO HIS INS. WE COMPARED COORDINATES AND THE RTING BTWN THE 2 INS'S. SINCE I DIDN'T CHANGE THE COORDINATES FROM 49N502 TO 48N50W, THE DISCREPANCY WASN'T FOUND. I THEN FILLED OUT THE AIREP FORM TO MAKE OUR POS RPTS. I FILLED OUT THE COORDINATES OF THE SCRATCH PAD WHERE I HAD WRITTEN DOWN THE ATC OCEANIC CLRNC WHERE THE CORRECT COORDINATE OF 48N50W WAS WRITTEN DOWN. ALL THE WAY ACROSS THE ATLANTIC I CHKED THE WAYPOINT COORDINATES AGAINST THE COMPUTERIZED FLT PLAN. WHEN I CHKED THE WAYPOINT 49N50W ON THE FLT PLAN, IT MATCHED THE INS. AT ABOUT 10 NM FROM 49N50W, I SAW ON MY SCRATCH PAD WHERE I HAD WRITTEN THE OCEANIC CLRNC 48N50W DIRECT YYT (TORBAY). SINCE WE WEREN'T IN RADAR CONTACT, I IMMEDIATELY INFORMED GANDER CTR THAT WE WERE PROCEEDING DIRECT 49N50W INSTEAD OF 48N50W. GANDER SAID PROCEED DIRECT 48N50W SQUAWK XXXX. I FEEL MY BIGGEST MISTAKE WAS I SHOULD HAVE WRITTEN THE OCEANIC CLRNC ON THE COMPUTER FLT PLAN WHERE I WOULD HAVE PICKED UP THE MISTAKE OF NOT XING OUT THE COORDINATES OF 49N50W FOR 48N50W. THINKING BACK OVER THIS TRIP, NOWHERE DURING THE OCEANIC XING DID MY FO PICK UP THE COMPUTER FLT PLAN OR THE AIREP FORM TO CHK FOR ANY MISTAKES. I FEEL I AM RESPONSIBLE FOR THE NAV ERROR. BUT, IF MY FO HAD LOOKED AT THE AIREP FORM, MY MISTAKE MIGHT HAVE BEEN FOUND LONG BEFORE IT WOULD HAVE BECOME A NAV ERROR.

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.