Narrative:

Clearance: jaaws 9 departure R507 gtk. After takeoff on heading 350 degrees, we were cleared direct to jaaws. While intercepting the 326 degree radial at jaaws, first officer coupled the autoplt and the aircraft experienced continuous yaw oscillations. First officer disengaged the autoplt while maintaining aircraft control, heading 305 degrees, wings level, climbing out of approximately FL200. Captain and flight engineer reviewed checklist for 'autoplt hardover any axis.' (this was the only aom procedure which seemed to apply.) shortly after, ATC asked if we were proceeding to utahs. At this point we had passed through the 326 degree radial and were on the 318 degree radial at 52 NM (approximately 4 NM left of course). We immediately turned to intercept the 326 degree radial. ZSU then cleared us direct to gtk. We informed ATC of our problem and continued the flight. Contributing factors: fatigue associated with an early morning local report time slowed scan and ability to prioritize correctly. Aircraft mechanical problem, particularly with it being a flight control problem, distraction attention away from navigation responsibilities. Supplemental information from acn 432413: fatiguing night flight 7 1/2 hours into a scheduled 12 hour duty day.

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Original NASA ASRS Text

Title: A NIGHTTIME DC8 FREIGHTER CREW IS DISTR BY A YAW DAMPER PROB AND FLIES PAST THE REQUIRED OUTBOUND RADIAL ON THE JAAWS 9 DEP PROC FROM SJU, PR.

Narrative: CLRNC: JAAWS 9 DEP R507 GTK. AFTER TKOF ON HDG 350 DEGS, WE WERE CLRED DIRECT TO JAAWS. WHILE INTERCEPTING THE 326 DEG RADIAL AT JAAWS, FO COUPLED THE AUTOPLT AND THE ACFT EXPERIENCED CONTINUOUS YAW OSCILLATIONS. FO DISENGAGED THE AUTOPLT WHILE MAINTAINING ACFT CTL, HDG 305 DEGS, WINGS LEVEL, CLBING OUT OF APPROX FL200. CAPT AND FE REVIEWED CHKLIST FOR 'AUTOPLT HARDOVER ANY AXIS.' (THIS WAS THE ONLY AOM PROC WHICH SEEMED TO APPLY.) SHORTLY AFTER, ATC ASKED IF WE WERE PROCEEDING TO UTAHS. AT THIS POINT WE HAD PASSED THROUGH THE 326 DEG RADIAL AND WERE ON THE 318 DEG RADIAL AT 52 NM (APPROX 4 NM L OF COURSE). WE IMMEDIATELY TURNED TO INTERCEPT THE 326 DEG RADIAL. ZSU THEN CLRED US DIRECT TO GTK. WE INFORMED ATC OF OUR PROB AND CONTINUED THE FLT. CONTRIBUTING FACTORS: FATIGUE ASSOCIATED WITH AN EARLY MORNING LCL RPT TIME SLOWED SCAN AND ABILITY TO PRIORITIZE CORRECTLY. ACFT MECHANICAL PROB, PARTICULARLY WITH IT BEING A FLT CTL PROB, DISTR ATTN AWAY FROM NAV RESPONSIBILITIES. SUPPLEMENTAL INFO FROM ACN 432413: FATIGUING NIGHT FLT 7 1/2 HRS INTO A SCHEDULED 12 HR DUTY DAY.

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.