Narrative:

Ord forecast for our arrival time is 6000 broken 9000 broken 5 mi visibility chance of 3 light snow. When receiving ord ATIS, WX was sky obscured 800 overcast 1 mi light snow. Shortly thereafter, we received a message from dispatch that runway 32L RVR was 2200 ft and 32R was 3200 ft. After leaving a holding pattern about 35 mi from ord, we are cleared to intercept the 32L localizer. RVR as reported by ord approach was 1600 ft. Minimums for runway 32L are 1800 RVR. Approach controller announced 'what we're doing is letting people shoot the approach, and make their decision upon reaching the decision ht.' we knew that statement was contrary to our company policy, and the FARS. WX as reported by approach control now is RVR 1800 ft, and at 7000 ft MSL we are cleared for the 32L ILS and begin down the GS. At this point, we believe we are legal to make the approach because we had 1800 ft RVR upon beginning down the GS. At about 5000 ft MSL, we are told the RVR is now 1400 ft. Then, at approximately 4000 ft we are told the RVR is 1000 ft. We were aware and had discussed the fact that there was a point on the approach, that if the RVR went below 1800 ft, that we could legally continue. We believed that point to be GS intercept. After landing we looked up the regulations, and to our amazement, found out that the point at which you can continue the approach when the RVR is less than 1800 ft is 'GS intercept as depicted on the profile.' that would have been 2500 ft. I believe we may have not been legal to continue below 2500 ft.

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Original NASA ASRS Text

Title: AN ACR MLG MADE AN INST APCH TO BELOW MINIMUMS.

Narrative: ORD FORECAST FOR OUR ARR TIME IS 6000 BROKEN 9000 BROKEN 5 MI VISIBILITY CHANCE OF 3 LIGHT SNOW. WHEN RECEIVING ORD ATIS, WX WAS SKY OBSCURED 800 OVCST 1 MI LIGHT SNOW. SHORTLY THEREAFTER, WE RECEIVED A MESSAGE FROM DISPATCH THAT RWY 32L RVR WAS 2200 FT AND 32R WAS 3200 FT. AFTER LEAVING A HOLDING PATTERN ABOUT 35 MI FROM ORD, WE ARE CLRED TO INTERCEPT THE 32L LOC. RVR AS RPTED BY ORD APCH WAS 1600 FT. MINIMUMS FOR RWY 32L ARE 1800 RVR. APCH CTLR ANNOUNCED 'WHAT WE'RE DOING IS LETTING PEOPLE SHOOT THE APCH, AND MAKE THEIR DECISION UPON REACHING THE DECISION HT.' WE KNEW THAT STATEMENT WAS CONTRARY TO OUR COMPANY POLICY, AND THE FARS. WX AS RPTED BY APCH CTL NOW IS RVR 1800 FT, AND AT 7000 FT MSL WE ARE CLRED FOR THE 32L ILS AND BEGIN DOWN THE GS. AT THIS POINT, WE BELIEVE WE ARE LEGAL TO MAKE THE APCH BECAUSE WE HAD 1800 FT RVR UPON BEGINNING DOWN THE GS. AT ABOUT 5000 FT MSL, WE ARE TOLD THE RVR IS NOW 1400 FT. THEN, AT APPROX 4000 FT WE ARE TOLD THE RVR IS 1000 FT. WE WERE AWARE AND HAD DISCUSSED THE FACT THAT THERE WAS A POINT ON THE APCH, THAT IF THE RVR WENT BELOW 1800 FT, THAT WE COULD LEGALLY CONTINUE. WE BELIEVED THAT POINT TO BE GS INTERCEPT. AFTER LNDG WE LOOKED UP THE REGS, AND TO OUR AMAZEMENT, FOUND OUT THAT THE POINT AT WHICH YOU CAN CONTINUE THE APCH WHEN THE RVR IS LESS THAN 1800 FT IS 'GS INTERCEPT AS DEPICTED ON THE PROFILE.' THAT WOULD HAVE BEEN 2500 FT. I BELIEVE WE MAY HAVE NOT BEEN LEGAL TO CONTINUE BELOW 2500 FT.

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.