Narrative:

We were cleared for a visual approach to runway 34R by seattle approach. Since we were only a few mi from the threshold this required an early turn. We were also instructed not to pass a B757, aircraft Y, that was established for runway 34L. I configured the aircraft for landing and joined the extended centerline for runway 34R. I saw what appeared to be a DC10, aircraft Z, approaching the hold lines of the same runway. Instead of holding short he was given position-and-hold. Seattle tower instructed us to execute a right 360 degrees. As we came about the 270 degree point we realized, aircraft west, a B737, was now established for runway 34L and would thus prevent us from finishing our turn. I rolled out of the turn early, crossed both extended ctrlines and completed the turn as soon as possible, but not before alarming another air carrier flight, aircraft V, for runway 34L. I suspect seattle approach and tower were not coordinating closely enough. Had they held aircraft Z this would not have occurred. I should have executed a go around rather than the right 360 degrees which put my flight into further peril.

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Original NASA ASRS Text

Title: AN ACR ASSIGNED A VISUAL APCH AT SEATTLE IS HANDED OFF TO TWR WHO ASSIGNS A 360 DEG TURN TO ACCOMMODATE TFC THAT HAS BEEN CLRED ON TO THE ASSIGNED RWY. UNABLE TO COMPLETE THE TURN BECAUSE OF TFC CONFLICT THE ACR CROSSES THE FINAL APCH COURSE OF TWO RWYS.

Narrative: WE WERE CLRED FOR A VISUAL APCH TO RWY 34R BY SEATTLE APCH. SINCE WE WERE ONLY A FEW MI FROM THE THRESHOLD THIS REQUIRED AN EARLY TURN. WE WERE ALSO INSTRUCTED NOT TO PASS A B757, ACFT Y, THAT WAS ESTABLISHED FOR RWY 34L. I CONFIGURED THE ACFT FOR LNDG AND JOINED THE EXTENDED CTRLINE FOR RWY 34R. I SAW WHAT APPEARED TO BE A DC10, ACFT Z, APCHING THE HOLD LINES OF THE SAME RWY. INSTEAD OF HOLDING SHORT HE WAS GIVEN POS-AND-HOLD. SEATTLE TWR INSTRUCTED US TO EXECUTE A R 360 DEGS. AS WE CAME ABOUT THE 270 DEG POINT WE REALIZED, ACFT W, A B737, WAS NOW ESTABLISHED FOR RWY 34L AND WOULD THUS PREVENT US FROM FINISHING OUR TURN. I ROLLED OUT OF THE TURN EARLY, CROSSED BOTH EXTENDED CTRLINES AND COMPLETED THE TURN AS SOON AS POSSIBLE, BUT NOT BEFORE ALARMING ANOTHER ACR FLT, ACFT V, FOR RWY 34L. I SUSPECT SEATTLE APCH AND TWR WERE NOT COORDINATING CLOSELY ENOUGH. HAD THEY HELD ACFT Z THIS WOULD NOT HAVE OCCURRED. I SHOULD HAVE EXECUTED A GAR RATHER THAN THE R 360 DEGS WHICH PUT MY FLT INTO FURTHER PERIL.

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.