IAP LOC APCH TO BELOW MINS.

Narrative

APCH HAD TOLD US TO EXPECT A DME LOC BACK COURSE TO RWY 27L; SO WE SET THE INSTS FOR THAT APCH. AT ABOUT 15 MI FROM THE ARPT; DETROIT SAID THE WX CONDITIONS WERE GOING DOWN AND TO NOW INTERCEPT THE LOC FOR RWY 9R. AT THIS POINT; WE WERE RUSHING TO SET UP FOR THE NEW APCH. THE 9R APCH AT PTK IS NORMALLY AN ILS; HOWEVER; THE GS WAS OTS. I REVIEWED THE APCH PLATE AND READ WHAT I THOUGHT WERE THE LOC 9R MINS. AFTER THE REVIEW; WE WERE CLRED FOR THE LOC 9R APCH. AFTER PASSING THE OM I STARTED OUR TIME AND USED OUR LORAN AS A XCHK FOR DISTANCE TO THE ARPT. THE COPLT STARTED HIS DSCNT TO 1230 FT MSL. UPON REACHING 1230 FT WE DID NOT SEE THE RWY OR LIGHTS. WE STILL HAD TIME TO GO; SO WE CONTINUED. AT APPROX 1.5 MI; I ELECTED TO TURN OFF THE LNDG LIGHTS IN AN ATTEMPT TO SEE THE RWY LIGHTS IN THE FOGGY CONDITIONS. VERY SHORTLY THEREAFTER; WE DID SEE THE RWY. I THEN ASKED THE COPLT FOR THE CTLS DUE TO THE LOWER THAN ANTICIPATED VISIBILITY. I MADE THE LNDG WITHOUT INCIDENT. PONTIAC TWR HAD CALLED THE RVR AT 6000 FT; I WOULD ESTIMATE 3000 FT BECAUSE I COULD ONLY SEE HALF OF THE 6200 FT RWY. AFTER TAXIING OFF THE RWY I HAD A FEELING SOMETHING ABOUT THE APCH WAS NOT NORMAL. AFTER SHUTTING THE ACFT DOWN I REREVIEWED THE APCH PLATE AND DISCOVERED THAT I HAD MISREAD THE MINS. I HAD READ THE ILS MINS WITH MM OTS; NOT THE LOC ONLY MIN WHICH IS 1520. IN RETROSPECT; I CAN'T BELIEVE I MADE SUCH A STUPID MISTAKE AND I AM LUCKY TO BE HERE. I THINK THE PROBLEM WAS CAUSED BY BEING RUSHED AND BEING TIRED -- WE HAD ALREADY FLOWN 4 APCHS TO MINS. TURB IN A NIGHT ENVIRONMENT. I THINK A GOOD SOLUTION TO THIS KIND OF PROBLEM IS TO HAVE THE COPLT READ THE APCH PLATE AS WELL AS THE CAPT AND VERIFY WHAT EACH OTHER HAS READ. THEN MAKE SURE THE MINS MAKE SENSE; LIKE 250 AGL FOR A NON PRECISION APCH? I ALSO THINK IT WOULD HAVE BEEN A GOOD IDEA TO HAVE DETROIT REVECTOR US AND GIVE US MORE TIME TO SET UP PROPERLY; ESPECIALLY WHEN WE WERE TIRED. I HAVE REALLY LEARNED A LESSON FROM THIS EXPERIENCE!