Narrative:

While being vectored for a night instrument approach at roc, the approach controller advised us that a PIREP from a flight that had just landed indicated that the prevailing visibility was actually greater than that being reported, so much so that the crew questioned the accuracy of the RVR equipment (minimums ILS runway 22 are RVR 2400 ft or 1/2 mi). As we continued on vectors, the controller updated the ATIS to include visibility of 3/4 mi (no RVR given at that time). He also gave us a second PIREP from another air carrier that concurred with the first report. We accepted the approach clearance with visibility greater than 1/2 mi and (what we considered unreliable) RVR of less than 2400 ft. After we had passed the FAF inbound, the tower updated the RVR to 2000 ft and then 2200 ft. Approaching 1000 ft MSL (decision altitude 760 ft), we picked up the approach lights and runway, as expected, and landed uneventfully. During taxi, we relayed our observation that affirmed the estimated visibility of 3/4 - 1 mi. The issue here is one of legality more than anything. Our operating specifications allow us to continue an approach inside the FAF with less than required RVR, as long as we get the RVR and the visual cues necessary to complete a stabilized approach to landing by the time we reach the cati decision altitude. In this case, we had more than the required prevailing visibility, but not the RVR. The contributing factors here were the 2 PIREPS and uncertainty whether RVR was still controling in this situation. (Although it was certainly suspect, the RVR system was still considered operational by ATC.) a secondary factor for me personally could have been fatigue in that I had awoken that morning at XA00. Combined, these factors affected the decision-making process.

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Original NASA ASRS Text

Title: A320 CREW QUESTIONS WHETHER THEY HAD LEGAL LNDG MINIMUMS AT ROC.

Narrative: WHILE BEING VECTORED FOR A NIGHT INST APCH AT ROC, THE APCH CTLR ADVISED US THAT A PIREP FROM A FLT THAT HAD JUST LANDED INDICATED THAT THE PREVAILING VISIBILITY WAS ACTUALLY GREATER THAN THAT BEING RPTED, SO MUCH SO THAT THE CREW QUESTIONED THE ACCURACY OF THE RVR EQUIP (MINIMUMS ILS RWY 22 ARE RVR 2400 FT OR 1/2 MI). AS WE CONTINUED ON VECTORS, THE CTLR UPDATED THE ATIS TO INCLUDE VISIBILITY OF 3/4 MI (NO RVR GIVEN AT THAT TIME). HE ALSO GAVE US A SECOND PIREP FROM ANOTHER ACR THAT CONCURRED WITH THE FIRST RPT. WE ACCEPTED THE APCH CLRNC WITH VISIBILITY GREATER THAN 1/2 MI AND (WHAT WE CONSIDERED UNRELIABLE) RVR OF LESS THAN 2400 FT. AFTER WE HAD PASSED THE FAF INBOUND, THE TWR UPDATED THE RVR TO 2000 FT AND THEN 2200 FT. APCHING 1000 FT MSL (DECISION ALT 760 FT), WE PICKED UP THE APCH LIGHTS AND RWY, AS EXPECTED, AND LANDED UNEVENTFULLY. DURING TAXI, WE RELAYED OUR OBSERVATION THAT AFFIRMED THE ESTIMATED VISIBILITY OF 3/4 - 1 MI. THE ISSUE HERE IS ONE OF LEGALITY MORE THAN ANYTHING. OUR OPERATING SPECS ALLOW US TO CONTINUE AN APCH INSIDE THE FAF WITH LESS THAN REQUIRED RVR, AS LONG AS WE GET THE RVR AND THE VISUAL CUES NECESSARY TO COMPLETE A STABILIZED APCH TO LNDG BY THE TIME WE REACH THE CATI DECISION ALT. IN THIS CASE, WE HAD MORE THAN THE REQUIRED PREVAILING VISIBILITY, BUT NOT THE RVR. THE CONTRIBUTING FACTORS HERE WERE THE 2 PIREPS AND UNCERTAINTY WHETHER RVR WAS STILL CTLING IN THIS SIT. (ALTHOUGH IT WAS CERTAINLY SUSPECT, THE RVR SYS WAS STILL CONSIDERED OPERATIONAL BY ATC.) A SECONDARY FACTOR FOR ME PERSONALLY COULD HAVE BEEN FATIGUE IN THAT I HAD AWOKEN THAT MORNING AT XA00. COMBINED, THESE FACTORS AFFECTED THE DECISION-MAKING PROCESS.

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.