Narrative:

The first officer was flying. The WX cavu except for a fog patch over the airport. As we turned onto the localizer, the approach lights and the approach end of the runway were clearly visible and remained so throughout the approach (ILS). Inside the outer marker while we were proceeding down the glide slope the tower called the RVV as 1/8 of a mi. I acknowledged and continued the approach thinking the visibility may be at or above minimums at the decision height. I then concentrated on the approach and landing by the first officer. Neither I nor the first officer made comment about the visibility nor initiated or called for a missed approach. The landing was completed well within the operational limits and capabilities of the aircraft and within my own capabilities. We taxied to the ramp and departed 20 mins later (the visibility was now VFR). It wasn't until the end of the day that I realized we had landed below minimum visibility, which I now recall was about 1/4 mi at its worst. In the future, instead of simply stating (among other items) the decision height, minimum visibility and the missed approach procedure, I will also include in the approach briefing 'a missed approach will be executed if visibility at decision height is less than minimum'. The oversight of the visibility was due to rapidity of visibility change (an error in not anticipating this possibility), the inexperience of the first officer who was concentrating on the ILS so much so that he didn't think about a missed approach when the visibility dropped, and that the visibility lowered in the flare. An emphasis on what to expect and specific actions under specific circumstances during the approach briefing perhaps may have precluded this occurrence by raising it to the fore of thought, during a busy phase of flight. Ps note: the first officer had 1700 hours total time. This was his second day out of training. I have 120 hours PIC in the aircraft.

Related reports:

Google
 

Original NASA ASRS Text

Title: COMMUTER LTT CONTINUED APCH FROM INSIDE THE OUTER MARKER AFTER TWR REPORTED VISIBILITY BELOW ARPT MINIMUMS FOR LNDG.

Narrative: THE F/O WAS FLYING. THE WX CAVU EXCEPT FOR A FOG PATCH OVER THE ARPT. AS WE TURNED ONTO THE LOC, THE APCH LIGHTS AND THE APCH END OF THE RWY WERE CLEARLY VISIBLE AND REMAINED SO THROUGHOUT THE APCH (ILS). INSIDE THE OUTER MARKER WHILE WE WERE PROCEEDING DOWN THE GLIDE SLOPE THE TWR CALLED THE RVV AS 1/8 OF A MI. I ACKNOWLEDGED AND CONTINUED THE APCH THINKING THE VISIBILITY MAY BE AT OR ABOVE MINIMUMS AT THE DECISION HEIGHT. I THEN CONCENTRATED ON THE APCH AND LNDG BY THE F/O. NEITHER I NOR THE F/O MADE COMMENT ABOUT THE VISIBILITY NOR INITIATED OR CALLED FOR A MISSED APCH. THE LNDG WAS COMPLETED WELL WITHIN THE OPERATIONAL LIMITS AND CAPABILITIES OF THE ACFT AND WITHIN MY OWN CAPABILITIES. WE TAXIED TO THE RAMP AND DEPARTED 20 MINS LATER (THE VISIBILITY WAS NOW VFR). IT WASN'T UNTIL THE END OF THE DAY THAT I REALIZED WE HAD LANDED BELOW MINIMUM VISIBILITY, WHICH I NOW RECALL WAS ABOUT 1/4 MI AT ITS WORST. IN THE FUTURE, INSTEAD OF SIMPLY STATING (AMONG OTHER ITEMS) THE DECISION HEIGHT, MINIMUM VISIBILITY AND THE MISSED APCH PROC, I WILL ALSO INCLUDE IN THE APCH BRIEFING 'A MISSED APCH WILL BE EXECUTED IF VISIBILITY AT DECISION HEIGHT IS LESS THAN MINIMUM'. THE OVERSIGHT OF THE VISIBILITY WAS DUE TO RAPIDITY OF VISIBILITY CHANGE (AN ERROR IN NOT ANTICIPATING THIS POSSIBILITY), THE INEXPERIENCE OF THE F/O WHO WAS CONCENTRATING ON THE ILS SO MUCH SO THAT HE DIDN'T THINK ABOUT A MISSED APCH WHEN THE VISIBILITY DROPPED, AND THAT THE VISIBILITY LOWERED IN THE FLARE. AN EMPHASIS ON WHAT TO EXPECT AND SPECIFIC ACTIONS UNDER SPECIFIC CIRCUMSTANCES DURING THE APCH BRIEFING PERHAPS MAY HAVE PRECLUDED THIS OCCURRENCE BY RAISING IT TO THE FORE OF THOUGHT, DURING A BUSY PHASE OF FLT. PS NOTE: THE F/O HAD 1700 HRS TOTAL TIME. THIS WAS HIS SECOND DAY OUT OF TRAINING. I HAVE 120 HRS PIC IN THE ACFT.

Data retrieved from NASA's ASRS site as of August 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.