Narrative:

When we received our oceanic clearance, an additional reporting point (58N, 60W) which was not on our preprinted flight plan had been inserted between 62N 50W and nain radio beacon. I inserted these positions and the captain checked them. Shortly after passing 62N, 50W, I began to tune in and copy the WX which distracted me from double checking the next position. Shortly after I began to copy the WX, the captain brought to my attention an apparent malfunction in all 3 INS's in that the longitude seemed to be frozen at 50W. In that I had just returned to the cockpit, it took me a few moments to orient myself and take a few radio bearings. Believing that we were south of course because of these bearings, we initiated a sharp right turn and notified ATC that our position was questionable and that we believed we were as much as 80 mi south of course. After checking the coordinates in waypoint position #4 and finding them to be 58N, 50W, we made the correction and ATC cleared us direct to nain. We had both been on duty for 10 hours and were very tired not having slept well the previous night in moscow due to the time change. We both saw what we expected to see.

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Original NASA ASRS Text

Title: ACR WDB GROSS NAVIGATIONAL ERROR BETWEEN GREENLAND AND NF.

Narrative: WHEN WE RECEIVED OUR OCEANIC CLRNC, AN ADDITIONAL RPTING POINT (58N, 60W) WHICH WAS NOT ON OUR PREPRINTED FLT PLAN HAD BEEN INSERTED BTWN 62N 50W AND NAIN RADIO BEACON. I INSERTED THESE POSITIONS AND THE CAPT CHKED THEM. SHORTLY AFTER PASSING 62N, 50W, I BEGAN TO TUNE IN AND COPY THE WX WHICH DISTRACTED ME FROM DOUBLE CHKING THE NEXT POS. SHORTLY AFTER I BEGAN TO COPY THE WX, THE CAPT BROUGHT TO MY ATTN AN APPARENT MALFUNCTION IN ALL 3 INS'S IN THAT THE LONGITUDE SEEMED TO BE FROZEN AT 50W. IN THAT I HAD JUST RETURNED TO THE COCKPIT, IT TOOK ME A FEW MOMENTS TO ORIENT MYSELF AND TAKE A FEW RADIO BEARINGS. BELIEVING THAT WE WERE S OF COURSE BECAUSE OF THESE BEARINGS, WE INITIATED A SHARP RIGHT TURN AND NOTIFIED ATC THAT OUR POS WAS QUESTIONABLE AND THAT WE BELIEVED WE WERE AS MUCH AS 80 MI S OF COURSE. AFTER CHKING THE COORDINATES IN WAYPOINT POS #4 AND FINDING THEM TO BE 58N, 50W, WE MADE THE CORRECTION AND ATC CLRED US DIRECT TO NAIN. WE HAD BOTH BEEN ON DUTY FOR 10 HRS AND WERE VERY TIRED NOT HAVING SLEPT WELL THE PREVIOUS NIGHT IN MOSCOW DUE TO THE TIME CHANGE. WE BOTH SAW WHAT WE EXPECTED TO SEE.

Data retrieved from NASA's ASRS site as of August 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.