B727 WINGTIP AND FLAP DAMAGE RESULTED DURING LNDG FROM AN APCH THAT WAS CONTINUED AFTER ATC RPTED VISIBILITY LESS THAN WHAT WAS LEGALLY REQUIRED. DAMAGE WAS DISCOVERED BY OUTBOUND FLC MEMBER'S PREFLT.

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NORMAL FLT FROM SLC TO BOI. BOI APCH CTL INDICATED RVR FOR RWY 10R WAS 2800 FT. I SET UP AND BRIEFED A CAT I ILS TO RWY 10R; AND COUPLED THE AUTOPLT. ONCE INSIDE THE FAF; TWR RPTED THE RVR HAD DECREASED TO 2000 FT. SINCE WE WERE INSIDE THE FAF; I KNEW THAT WE WERE LEGAL TO CONTINUE THE APCH AND I VERBALIZED THIS WITH MY CREW. ANTICIPATING A POSSIBLE MAP; I ONCE AGAIN REVIEWED THE ILS RWY 10R MAP PROCS WITH THE CREW. THE AUTOPLT COUPLED APCH SEEMED NORMAL; WITH THE FLT DIRECTOR AND RAW DATA IN AGREEMENT. AT MORE THAN 100 FT ABOVE MINIMUMS I COULD SEE THE SEQUENCED FLASHERS. AT 50 FT ABOVE MINIMUMS; I HAD THE THRESHOLD LIGHTS; RWY EDGE LIGHTS AND RWY IN SIGHT. AT ABOUT 60 FT ABOVE THE RWY; I DISENGAGED THE AUTOPLT IN PREPARATION FOR LNDG. THE SIGHT PICTURE LOOKED GOOD WITH THE ACFT ALIGNED DOWN THE CTR OF THE RWY. LNDG WAS ON SPD IN THE TOUCHDOWN ZONE. JUST AS THE L MAIN GEAR TOUCHED DOWN I IMMEDIATELY SAW A RAPID DRIFT TO THE R TOWARD THE RWY EDGE LIGHTS. THE FO LATER SAID THAT HE THOUGHT HE FELT THE ACFT START TO SLIP TO THE R ABOUT THE TIME OF AUTOPLT DISENGAGEMENT; BUT NEITHER CREW MEMBER VISUALLY DETECTED ANY MOVEMENT. WHEN I NOTICED THE RATE OF THE ACFT SLIDING TO THE R; IT WAS OBVIOUS THAT SUBSTANTIAL CTL INPUTS WOULD BE NEEDED TO STAY ON THE RWY. FROM THAT POINT; IT WAS PURE PLT REACTION WITH RUDDER AND AILERON CTLS BEING USED. AFTER CTLING THE ACFT TO CTRLINE AND WHILE COMPLETING ROLLOUT; THE ANTI-SKID WAS CYCLING; PROBABLY DUE TO THE RWY BEING WET DUE TO PREVIOUS PRECIPITATION AND A SURFACE TEMP OF 27 DEGS. AFTER COMPLETING THE LNDG AND TAXI TO THE GATE; A RPT BY THE OUTBOUND SO AND SUBSEQUENT INSPECTION REVEALED DAMAGE TO THE L WINGTIP AREA AND FLAPS. DURING THIS INSPECTION THE RAMP AREA WAS ICY AND SLIPPERY. LOGBOOK ENTRIES WERE MADE AND THE ACFT TURNED OVER TO MAINT. I THEN CONTACTED THE DISPATCHER AND BOI STATION MGR TO CONTINUE MY RPTING REQUIREMENTS. I BELIEVE THAT AN AUTOPLT INDUCED L TO R CORRECTION JUST BEFORE DISENGAGEMENT; PLUS A QUARTERING TAILWIND OF 310 DEGS AT 6 KTS AND AN UNRPTED ICY RWY; ALL CONTRIBUTED TO THIS INCIDENT. BETTER ILS SIGNAL PROTECTION WOULD LESSEN AUTOPLT CORRECTIONS; UNLESS THIS CORRECTION WAS CAUSED BY A LOW ALT WIND CHANGE. A RWY CONDITION RPT ABOUT THE ICY RWY WOULD HAVE HELPED; I WOULD HAVE ABANDONED THE APCH UNLESS I ALSO HAD A BRAKING ACTION RPT. SUPPLEMENTAL INFO FROM ACN 323074: ACFT TOUCHED DOWN APPROX 1200 FT DOWN RWY IN TOUCHDOWN ZONE; ON L MAIN GEAR; AND SLIGHTLY R OF CTRLINE. ACFT PICKED UP A R DRIFT AND CAPT (FLYING) SIMULTANEOUSLY PUT IN L AILERON AND RUDDER WHILE LOWERING OTHER MAIN AND NOSE GEAR. ON POSTFLT WALKAROUND FOUND DAMAGE TO L WINGTIP; L LEADING EDGE AND TRAILING EDGE FLAP. WE FOUND IT HAPPENED ON TOUCHDOWN WHEN CORRECTING FOR R DRIFT. DAMAGE WAS MOSTLY COSMETIC AS ACFT WAS FLOWN TO MAINT BASE THE NEXT DAY. SUPPLEMENTAL INFO FROM ACN 322929: DURING TOUCHDOWN; I DETECTED A SLIGHT SLIPPING SENSATION AND THE ACFT APPEARED TO DRIFT TO THE R; BUT I SAW THAT THE CAPT ALREADY HAD A L BANK IN; AND THE ACFT CORRECTED BACK TO CTRLINE.