B737 CREW LANDED AT SEA WITHOUT LNDG CLRNC.

Narrative

FLT WAS INBOUND TO SEA AND IN CTL OF SEA APCH CTL. SPRING WX IN AREA INCLUDED RAIN SHOWERS AND HIGH WINDS; RESULTING IN 25-30 KT XWINDS AND GAINS/LOSSES OF 15 KTS AIRSPD RPTED BY PREVIOUS ACFT; AS WELL AS ON THE ATIS RPT. JUST AS WE WERE MAKING THE BASE-TO-FINAL TURN; APCH HANDED US OFF TO SEA TWR AND IN THE SAME XMISSION SAID TO 'MAINTAIN 170 KTS TO BOEING' MEANING BOEING FIELD ARPT ABOUT 2 MI AHEAD. THIS WAS A VERY BUSY MOMENT; AS A TREMENDOUS AMOUNT OF WIND DRIFT WAS BLOWING US ONTO THE FINAL APCH COURSE (PATH). I WAS FOCUSING MY ATTN ON THIS TO ENSURE THE FO WAS GOING TO ROLL OUT ON THE EXTENDED CTRLINE OF RWY 16R; AS ANOTHER ACFT TO OUR L WAS APCHING RWY 16L FROM THE N. MEANWHILE; THE FO WAS TRYING TO SLOW TO THE 170 KTS ADVISED BY THE CTLR; AND BEGAN CALLING FOR FLAP EXTENSIONS AND SETTING SPDS IN THE SPD WINDOW ON THE MCP. IT WAS A LITTLE TURBULENT; AND THE AIRSPD BEGAN THE FLUCTUATIONS OF +/-15 KTS AS ADVERTISED BY ATIS; ETC. WE FINISHED CONFIGURING AND CONTINUED TO THE RWY AND LANDED. IT WAS WHEN WE TURNED OFF ON THE HIGH SPD TURNOFF BTWN RWY 16R&L THAT THE FO GAVE THE ACFT BACK TO ME TO TAXI TO THE GATE. HE LOOKED DOWN TO THE RADIO PANEL AND SAID 'I DON'T THINK WE EVER MADE IT TO TWR.' I HAD THAT SINKING FEELING OF REALIZATION IN MY STOMACH WHEN I REALIZED HE WAS RIGHT! HE CONTACTED GND AND THAT CTLR SAID 'GO BACK TO TWR AND HOLD SHORT OF THE L FOR DEPARTING TFC.' (NO TONE OF ALARM IN HIS VOICE; WHATSOEVER!) TWR WAS CALLED; AND THE TWR CTLR SAID 'CONTINUE HOLDING SHORT.' HE THEN CROSSED US OVER RWY 16L AND WE CONTACTED GND PER HIS INSTRUCTIONS. GND MERELY CLRED US TO OUR GATE WITH NO APPARENT CONCERN OVER THE EVENT; AS FAR AS WE COULD TELL. CLRLY; I MUST DEVELOP A NEW TECHNIQUE TO ENSURE A LNDG CLRNC HAS BEEN OBTAINED; THAT IS IMMUNE TO DISTRS. THE ONE I HAD BEEN USING FOR YRS (NOT TURNING ON THE OUTBOARD LNDG LIGHTS UNTIL CLRED TO LAND) LET ME DOWN TODAY. PERHAPS A MENTAL CHK; AT SAY 1000 FT AGL; WOULD BE BETTER. NOTE: THE ABSENCE OF A LNDG CLRNC WAS NOT DETECTED EITHER BY ME; MY FO; OR BY THE CAPT OF ANOTHER MAJOR ACR IN THE JUMP SEAT! SUPPLEMENTAL INFO FROM ACN 474039: ON THIS PARTICULAR DAY; RAINSHOWERS WERE PASSING THROUGH THE SEATTLE AREA; CREATING SMALL STORM CELLS; AND BROKEN CLOUDS AT 3500 FT WITH 10 MI VISIBILITY. WINDS WERE RPTED 190 DEGS AT 18 KTS GUSTING TO 27 KTS. LLWS ADVISORY WAS IN EFFECT WITH 'GAINS AND LOSSES OF 15 KTS ON FINAL APCH.' OUR FLT WAS 'CLRED FOR A VISUAL APCH TO RWY 16R SEATAC ARPT; CONTACT TWR OVER BOEING FIELD.' THERE WAS A B727 LINE ABREAST OF US MAKING AN APCH TO RWY 16L. WE FOUND THAT THE WIND READOUT ON THE FMC WAS 230 DEGS AT 33 KTS MAGNETIC ON FINAL -- MORE XWIND THAN RPTED. GAINS AND LOSSES WERE AT LEAST 15 KTS. I WAS THE PF; AND WAS CONCERNED WITH CONFIGURING THE ACFT; FLYING A STABILIZED APCH; AND STAYING ON RWY CTRLINE; SO AS NOT TO DRIFT AND CREATE A CONFLICT WITH THE B727 APCHING THE ADJACENT RWY. THE APCH; LNDG AND ROLLOUT WENT FINE; AND I XFERRED CTL TO THE CAPT AFTER ENTERING A HIGHSPD TXWY. AT THAT POINT I LOOKED DOWN AT THE RADIO AND NOTICED THAT WE WERE STILL ON APCH CTL FREQ. WE HAD LANDED WITHOUT CONTACTING THE TWR! I NORMALLY CONFIRM OUR ACFT'S CONFIGN AND THAT WE ARE 'CLRED TO LAND' A COUPLE OF TIME ON FINAL. THIS PARTICULAR DAY; I WAS BUSY AND HADN'T CONFIRMED WE WERE 'CLRED TO LAND' WITH TWR. AFTER THIS OCCURRENCE; I WILL MENTALLY RE-EMPHASIZE THE NECESSITY TO CONFIRM WE ARE 'CLRED TO LAND' AND OUR CONFIGN ON FINAL APCH.