B737 FLT CREW DEVIATES FROM PUBLISHED VISUAL APCH COURSE INTO SEA.

Narrative

WE WERE VECTORED FROM THE E FOR THE 'MALL VISUAL' TO RWY 34L AT SEATTLE. IT WAS EARLY MORNING WITH THE SUN AT A LOW ANGLE AND A BIT HAZY. WE WERE AT 5000 FT HEADING W TOWARD THE MALL AREA WHEN THE CTLR ASKED US TO RPT THE MALL IN SIGHT. I HAD THE ILS TO RWY 34L SET IN; AND SET A POINT IN THE LNAV 8 MI OUT (LOCATION OF THE MALL). WE HAD PLENTY OF INFO TO BACK UP OUR POS. SHORTLY; WE SAW SOME ROOF TOPS AHEAD; IN THE LIGHT HAZE; THAT WE WERE BOTH SURE WAS THE MALL. I BECAME FIXATED ON THIS POINT SO THAT I COULD TURN FINAL JUST S OF THIS POS. AS WE APCHED THE AREA; I WAS AT THE RECOMMENDED 3000 FT. AS I GOT CLOSER; I STARTED A SLIGHT DSCNT TO FOLLOW THE GS AND BEGAN A TURN TOWARD THE RADIAL. APCH CORRECTED US BY SAYING WE SHOULD BE AT 3000 FT TILL THE MALL AND WE NEEDED TO TURN L. THAT WAS THE FIRST TIME WE REALIZED THAT WE WEREN'T LOOKING AT THE MALL; BUT SOME LARGE WHITE ROOFED COMMERCIAL BUILDINGS E OF THE MALL. THE GS WAS ACTUALLY A FALSE GS SEVERAL DEGS E OF THE ACTUAL DESIRED COURSE. WE CORRECTED AND FINISHED THE APCH UNEVENTFULLY. I HAD MORE THAN ENOUGH EQUIP TO HELP ME FIND THE CORRECT COURSE GUIDANCE. THERE WERE ACFT AHEAD OF ME THAT DID THE APCH FINE. WE BOTH GOT FIXATED ON THE WRONG POINT. THE HAZE IMPAIRED VISIBILITY AS THE SUN WAS AT A LOW ANGLE IN THE SKY; BUT IT DIDN'T TRIGGER ANY ALARM BECAUSE WE WERE SO SURE WE WERE LOOKING AT THE RIGHT POINT. THE ONLY THING THAT COULD HAVE PREVENTED THIS WOULD HAVE BEEN TO RELY ON MY INSTS MORE. HOWEVER; THIS WAS A VISUAL APCH AND WE WERE BELIEVING OUR EYES. WHEN THE VISIBILITY IS GOOD ENOUGH FOR THE MALL VISUAL; BUT LESS THAN PERFECT; THERE IS A LARGE GROUP OF BUILDINGS E OF THE MALL THAT IS VERY EASY TO CONFUSE.