ACR PLT DEVIATES FROM LOC.

Narrative

WE WERE BEING VECTORED FOR AN ILS RWY 30L AT SJC. THE WX THAT MORNING WAS RPTED AS 21 BROKEN; 40 OVCST; AND 10 MI VISIBILITY. ARRS COULD EXPECT AN ILS RWY 30L TO A VISUAL SINCE THE CLOUD LAYER WAS SO HIGH. THE FO WAS THE PF AND I; THE CAPT; WAS THE PNF. OUR ARR WAS FROM THE N; AND SINCE WE CROSS OVER THE TOP OF SAN FRANCISCO; BAY APCH HAD KEPT US HIGH. WE WERE AT APPROX 6000 FT MSL DSNDING WHEN WE GOT THE CLRNC TO INTERCEPT THE LOC ON A 320 DEG HDG AND MAINTAIN 3000 FT MSL UNTIL ESTABLISHED; CLRED FOR THE APCH. THIS VECTOR PUT US ON APPROX A 10 MI FINAL. THE GS INTERCEPT ALT FOR THAT SEGMENT IS 2700 FT MSL. NEEDLESS TO SAY; WE WERE VERY HIGH AND TRYING TO SLOW DOWN AND GO DOWN AT THE SAME TIME. THE FO WAS TUNED IN TO THE ILS WHILE I WAS TUNED IN TO THE SJC VOR. THIS IS A COMMON PRACTICE SINCE THE ILS DOES NOT HAVE DME. LOOKING ACROSS THE COCKPIT; I SAW THE FO INTERCEPT THE LOC; SO I DIVERTED MY ATTN TO CONFIGURING THE ACFT AS WELL AS GETTING THE BEFORE LNDG CHKLIST COMPLETED. WHEN I HAD FINISHED COMPLETING THE CHKLIST; THE FO TOLD ME THAT HE WAS GETTING INTERMITTENT GS FLAGS; SO I DECIDED TO JOIN HIM ON THE ILS FREQ ON THE #1 NAV. WHEN IT WAS IDENTED; I NOTICED THE FO HAD DRIFTED OFF COURSE TO THE L; APPROX 1 1/2 DOTS ON THE CDI. I TOLD HIM TO TURN R AND CTR THE NEEDLE. IN HIS PREOCCUPATION OF TRYING TO CATCH UP WITH THE GS; HE HAD DRIFTED TO THE L OF COURSE. SINCE I WAS NOT ON THE ILS FREQ YET; I WAS UNABLE TO CATCH HIS ERROR IMMEDIATELY. WE ENDED UP GETTING BACK ON COURSE AND MADE A NORMAL APCH AND LNDG. I THINK INITIALLY WHAT CAUSED THE PROB WAS BAY APCH VECTORING US TO INTERCEPT THE ILS AT TOO HIGH OF AN ALT. THE SECOND PROB I SEE IS HAVING EACH PLT ON DIFFERENT FREQS. ALTHOUGH DME IS NOT REQUIRED FOR THE APCH; IT IS VERY NICE TO HAVE TO GAUGE WHETHER YOU ARE TOO HIGH UNTIL INTERCEPTING THE GS. IF I HAD BEEN ON THE SAME FREQ AS MY FO; I WOULD HAVE IMMEDIATELY SEEN THE INITIAL DEV. BUT SINCE I HAD TO TRY TO MONITOR THE APCH BY LOOKING ACROSS THE COCKPIT; I COULD NOT INITIALLY CATCH THE MISTAKE.