Narrative:

Bos ATIS reported 4000 ft broken, 7 mi visibility, ILS to runway 4R. Did not fly ILS precisely expecting visual conditions early in the approach. At 1500-2000 ft AGL, I asked the first officer to ask the tower controller what the current visibility was. The tower controller replied, '7 mi.' we finally saw the approach lights well off to the right just before reaching ILS minimums. I made a quick jog to the right, realigned the aircraft with the runway and landed firmly on runway 4R. A thick fog bank was over the water and the approach lights but the runway and airport was as reported. Obviously, the fog bank was visible from the tower but was not reported. If fog bank had been reported I would have flown the ILS more precisely. In the future I will be more suspect of reported WX conditions (and be especially alert for fog banks over bodies of water near runways) and I will execute a missed approach when displaced that far from the extended runway centerline. Also, observable WX phenomena such as fog banks should be mentioned on ATIS and by tower/approach controllers to help prevent similar occurrences in the future.

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Original NASA ASRS Text

Title: HDG TRACK DEV DURING IAP ILS APCH CREATES NEED FOR PIC, PF, TO MAKE A 'MINI' SIDESTEP MANEUVER IN ORDER TO LAND HIS MLG. RPTR WAS FLYING A 'LOOSE' APCH AS WX WASN'T EXPECTED TO BE POOR AT ARPT.

Narrative: BOS ATIS RPTED 4000 FT BROKEN, 7 MI VISIBILITY, ILS TO RWY 4R. DID NOT FLY ILS PRECISELY EXPECTING VISUAL CONDITIONS EARLY IN THE APCH. AT 1500-2000 FT AGL, I ASKED THE FO TO ASK THE TWR CTLR WHAT THE CURRENT VISIBILITY WAS. THE TWR CTLR REPLIED, '7 MI.' WE FINALLY SAW THE APCH LIGHTS WELL OFF TO THE R JUST BEFORE REACHING ILS MINIMUMS. I MADE A QUICK JOG TO THE R, REALIGNED THE ACFT WITH THE RWY AND LANDED FIRMLY ON RWY 4R. A THICK FOG BANK WAS OVER THE WATER AND THE APCH LIGHTS BUT THE RWY AND ARPT WAS AS RPTED. OBVIOUSLY, THE FOG BANK WAS VISIBLE FROM THE TWR BUT WAS NOT RPTED. IF FOG BANK HAD BEEN RPTED I WOULD HAVE FLOWN THE ILS MORE PRECISELY. IN THE FUTURE I WILL BE MORE SUSPECT OF RPTED WX CONDITIONS (AND BE ESPECIALLY ALERT FOR FOG BANKS OVER BODIES OF WATER NEAR RWYS) AND I WILL EXECUTE A MISSED APCH WHEN DISPLACED THAT FAR FROM THE EXTENDED RWY CTRLINE. ALSO, OBSERVABLE WX PHENOMENA SUCH AS FOG BANKS SHOULD BE MENTIONED ON ATIS AND BY TWR/APCH CTLRS TO HELP PREVENT SIMILAR OCCURRENCES IN THE FUTURE.

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.