Narrative:

WX at sea had been variable for some time - from RVR 1000 variable 1400 to near VFR. It was first officer's leg and sea ATIS reported 1 1/2 mi visibility. Approach requested our RVR requirements, and we responded 700 ft (CAT IIIA). No mention was made at that time of actual runway 16R RVR. ATIS still reported 1 1/2 mi. On downwind approach reported runway 16R RVR as 700-800-1100 for takeoff, mid, and rollout. Shortly thereafter we were turned on base. The workload increased significantly at that point as we shifted PF and PNF responsibilities. The base leg was relatively short. We should have requested vectors to give us more time to set up. We were shifted to tower frequency, and we believe the transfer switch was moved. Either it was moved or it was inadvertently switched back to approach. On short final, I could not remember receiving landing clearance, and at the same time the first officer called approaching minimums' and 'I have the stobes'. I requested landing information. At that point I had good visual on the runway. Tower responded with landing clearance. It simply did not register at the time, but in retrospect, the first officer and I believe the tower had said '...RVR 600....' we are simply not sure if the 600 reading referred to takeoff, mid, or rollout. I might have anticipated the situation better and been better prepared for the varying conditions. While I realize the ATC system is often overloaded, the cockpit of a 2 pilot airplane can quickly become overloaded as well. It is imperative that ATC provide accurate and timely information.

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Original NASA ASRS Text

Title: AN ACR LANDED BELOW MINIMUMS IN RAPIDLY DETERIORATING WX CONDITIONS.

Narrative: WX AT SEA HAD BEEN VARIABLE FOR SOME TIME - FROM RVR 1000 VARIABLE 1400 TO NEAR VFR. IT WAS FO'S LEG AND SEA ATIS RPTED 1 1/2 MI VISIBILITY. APCH REQUESTED OUR RVR REQUIREMENTS, AND WE RESPONDED 700 FT (CAT IIIA). NO MENTION WAS MADE AT THAT TIME OF ACTUAL RWY 16R RVR. ATIS STILL RPTED 1 1/2 MI. ON DOWNWIND APCH RPTED RWY 16R RVR AS 700-800-1100 FOR TKOF, MID, AND ROLLOUT. SHORTLY THEREAFTER WE WERE TURNED ON BASE. THE WORKLOAD INCREASED SIGNIFICANTLY AT THAT POINT AS WE SHIFTED PF AND PNF RESPONSIBILITIES. THE BASE LEG WAS RELATIVELY SHORT. WE SHOULD HAVE REQUESTED VECTORS TO GIVE US MORE TIME TO SET UP. WE WERE SHIFTED TO TWR FREQ, AND WE BELIEVE THE TRANSFER SWITCH WAS MOVED. EITHER IT WAS MOVED OR IT WAS INADVERTENTLY SWITCHED BACK TO APCH. ON SHORT FINAL, I COULD NOT REMEMBER RECEIVING LNDG CLRNC, AND AT THE SAME TIME THE FO CALLED APCHING MINIMUMS' AND 'I HAVE THE STOBES'. I REQUESTED LNDG INFO. AT THAT POINT I HAD GOOD VISUAL ON THE RWY. TWR RESPONDED WITH LNDG CLRNC. IT SIMPLY DID NOT REGISTER AT THE TIME, BUT IN RETROSPECT, THE FO AND I BELIEVE THE TWR HAD SAID '...RVR 600....' WE ARE SIMPLY NOT SURE IF THE 600 READING REFERRED TO TKOF, MID, OR ROLLOUT. I MIGHT HAVE ANTICIPATED THE SIT BETTER AND BEEN BETTER PREPARED FOR THE VARYING CONDITIONS. WHILE I REALIZE THE ATC SYS IS OFTEN OVERLOADED, THE COCKPIT OF A 2 PLT AIRPLANE CAN QUICKLY BECOME OVERLOADED AS WELL. IT IS IMPERATIVE THAT ATC PROVIDE ACCURATE AND TIMELY INFO.

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.