MDT ON TRAINING FLT QUESTIONS APCH AND LNDG WITH MINIMUMS LOW.

Narrative

A TRAINING FLT WAS BEING CONDUCTED FOR A FO. NUMEROUS AND MULTIPLE APCHS WERE EXECUTED TO MFD. THE WX WAS UP AND DOWN THROUGHOUT THE AFTERNOON DUE TO PRECIPITATION AND FOG. AN ILS RWY 32 APCH WAS CONDUCTED TO RWY 32 AT MFD ARPT. THE WX WAS RAIN/FOG (RVR 2400 FT) WHEN THE APCH WAS INITIATED. INSIDE THE FINAL APCH FIX (OM; GS INTERCEPT) APCH CTL TOLD US TO CONTACT THE MFD TWR. ON APPROX A 2-3 MI FINAL THE TWR WAS CONTACTED AND A CLRNC FOR THE OPTION TO RWY 32 WAS RECEIVED. THE TWR ALSO STATED THE RVR WAS AT 2000 FT. WHEN 100 FT ABOVE DECISION ALT WAS REACHED THE APCH LIGHTING SYS WAS IN FULL VIEW. WE CONTINUED THE APCH TO THE DECISION ALT; AT WHICH TIME THE RWY ENVIRONMENT (THRESHOLD MARKINGS; TOUCHDOWN ZONE; AND CTRLINE MARKINGS) CAME INTO FULL VIEW. THE ACFT WAS IN A NORMAL POS TO LAND AND THE RWY ENVIRONMENT WAS IN SIGHT. THE FO (PNF) CALLED VISUAL AND WE PROCEEDED BELOW DECISION ALT VISUALLY FOR A FULL STOP LNDG ON RWY 32. IN EVALUATING THE SIT; WE COULD HAVE ABANDONED THE APCH ONCE THE 2000 FT RVR RPT WAS RECEIVED AND WE HAD REACHED THE MISSED APCH POINT. BUT AS WE APCHED 100 FT ABOVE DECISION ALT; WE SAW THE APPROPRIATE ENVIRONMENT (RWY; LIGHTING SYS) AND CONTINUED. WE HAD THE REQUIRED FLT VISIBILITY (FROM COCKPIT) ALTHOUGH THE RPTED RVR WAS 2000 FT AND 2400 FT RVR IS PUBLISHED ON PLATE. THIS HAS ALWAYS SEEMED TO BE A GRAY AREA (PART 91) AND I; UNFORTUNATELY; DO NOT HAVE THE AGE OLD ANSWER.