Narrative:

First officer was flying on radar vector. He had been on duty since previous late evening, all night, and I had started my day at early morning. While abeam fix on filed routing, first officer started turn toward airway. My lack of attention did not catch this turn until 20 degrees from assigned heading when I brought this to his attention. We had started turn to original heading when ZBW notified us of the deviation and promptly reassigned a new heading. I don't believe a conflict occurred, but when lack of good rest occurred, inattn and lack of discipline becomes very easy and obviously could have been very serious.

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Original NASA ASRS Text

Title: A DC9 FO STARTS A TURN AWAY FROM THE ASSIGNED HDG ISSUED BY ZBW, 15 MI N OF ALB, NY.

Narrative: FO WAS FLYING ON RADAR VECTOR. HE HAD BEEN ON DUTY SINCE PREVIOUS LATE EVENING, ALL NIGHT, AND I HAD STARTED MY DAY AT EARLY MORNING. WHILE ABEAM FIX ON FILED ROUTING, FO STARTED TURN TOWARD AIRWAY. MY LACK OF ATTN DID NOT CATCH THIS TURN UNTIL 20 DEGS FROM ASSIGNED HDG WHEN I BROUGHT THIS TO HIS ATTN. WE HAD STARTED TURN TO ORIGINAL HDG WHEN ZBW NOTIFIED US OF THE DEV AND PROMPTLY REASSIGNED A NEW HDG. I DON'T BELIEVE A CONFLICT OCCURRED, BUT WHEN LACK OF GOOD REST OCCURRED, INATTN AND LACK OF DISCIPLINE BECOMES VERY EASY AND OBVIOUSLY COULD HAVE BEEN VERY SERIOUS.

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.