Narrative:

While climbing out fll en route to bdl, after being handed off to center, ATC cleared us to 'turn left 030 degrees and intercept AR7.' we glanced at our FMC map display while we turned and I said to the captain, 'we won't intercept AR7 on this heading.' that incorrect observation on my part was the root cause of the problem, because the captain then interpreted the situation as I had stated it. In actuality, 030 degree heading was a good heading and would have taken us to AR7. What we were looking at on our CRT map was a direct line from fll to our first filed/cleared waypoint of beean (see diagram next page). At that point, I pulled out my high 6 chart to confirm my interpretation of the CRT map. While I was looking in the chart, the captain selected LNAV, thinking we had already crossed AR7. The aircraft responded by turning back to the right (to a heading very close to an original heading) to intercept the CRT map course line (that we thought was AR7). Because I was busy referencing my chart, I was not aware we had turned back to the right. (However, I would have concurred, had I known.) once I referenced the chart, I realized our error and began to give the captain the data to enter into the FMC in order to correctly display AR7. At that point, center called and scolded us for 'not turning to 030 degrees, as told,' and said, 'turn immediately--you have widebody transport traffic ahead.' we complied and were subsequently cleared direct to a fix further down AR7. No other comments were made by center about the incident.

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Original NASA ASRS Text

Title: ACR LGT TRACK HEADING DEVIATION.

Narrative: WHILE CLBING OUT FLL ENRTE TO BDL, AFTER BEING HANDED OFF TO CENTER, ATC CLRED US TO 'TURN LEFT 030 DEGS AND INTERCEPT AR7.' WE GLANCED AT OUR FMC MAP DISPLAY WHILE WE TURNED AND I SAID TO THE CAPT, 'WE WON'T INTERCEPT AR7 ON THIS HDG.' THAT INCORRECT OBSERVATION ON MY PART WAS THE ROOT CAUSE OF THE PROB, BECAUSE THE CAPT THEN INTERPRETED THE SITUATION AS I HAD STATED IT. IN ACTUALITY, 030 DEG HDG WAS A GOOD HDG AND WOULD HAVE TAKEN US TO AR7. WHAT WE WERE LOOKING AT ON OUR CRT MAP WAS A DIRECT LINE FROM FLL TO OUR FIRST FILED/CLRED WAYPOINT OF BEEAN (SEE DIAGRAM NEXT PAGE). AT THAT POINT, I PULLED OUT MY HIGH 6 CHART TO CONFIRM MY INTERP OF THE CRT MAP. WHILE I WAS LOOKING IN THE CHART, THE CAPT SELECTED LNAV, THINKING WE HAD ALREADY CROSSED AR7. THE ACFT RESPONDED BY TURNING BACK TO THE RIGHT (TO A HDG VERY CLOSE TO AN ORIGINAL HDG) TO INTERCEPT THE CRT MAP COURSE LINE (THAT WE THOUGHT WAS AR7). BECAUSE I WAS BUSY REFERENCING MY CHART, I WAS NOT AWARE WE HAD TURNED BACK TO THE RIGHT. (HOWEVER, I WOULD HAVE CONCURRED, HAD I KNOWN.) ONCE I REFERENCED THE CHART, I REALIZED OUR ERROR AND BEGAN TO GIVE THE CAPT THE DATA TO ENTER INTO THE FMC IN ORDER TO CORRECTLY DISPLAY AR7. AT THAT POINT, CENTER CALLED AND SCOLDED US FOR 'NOT TURNING TO 030 DEGS, AS TOLD,' AND SAID, 'TURN IMMEDIATELY--YOU HAVE WDB TFC AHEAD.' WE COMPLIED AND WERE SUBSEQUENTLY CLRED DIRECT TO A FIX FURTHER DOWN AR7. NO OTHER COMMENTS WERE MADE BY CENTER ABOUT THE INCIDENT.

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.