Narrative:

Takeoff minimum WX. At the gate prior to departure, ATIS reported low ceilings and 1 SM visibility with all runways in use. The book showed runway 24 as primary, along with data for runway 6. We briefed a runway 24 takeoff with RVR touchdown 6, mid RVR 6, rollout RVR 6 as minimums. We then briefed our plan for a return to the airport, if necessary, and set the radios for the ILS runway 6, which provided lowest minimums. Prior to our call for taxi, an aircraft ahead of us requested runway 6. Our book showed a higher runway limited weight for runway 6 (a better safety margin), so when ATC asked for our runway preference, we requested and were cleared to runway 6. We did not check runway 6 takeoff minimums. There was patchy fog on the airport, but both taxiway visibility and runway visibility were very good. While taxiing, I recall hearing ATC broadcast some fairly high RVR's without a request for an acknowledgement. At the time, I recalled the RVR touchdown 6, mid RVR 6, rollout RVR 6 RVR we had briefed for runway 24, and with our present good visibility, pressed on, making an uneventful takeoff and departure. It was not until some 5 hours and 2 legs after when preparing for another departure that the thought occurred to me that we never specifically checked bhm runway 6 departure minimums. When I checked, I found a requirement for an RVR of 50 or 1 SM visibility. We had an ATIS reported visibility of 1 SM, but since I cannot recall the specific RVR reported during taxi out, we may have departed runway 6 with less than minimum visibility.

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Original NASA ASRS Text

Title: FK10 CREW MAY HAVE TAKEN OFF BELOW MINIMUMS.

Narrative: TKOF MINIMUM WX. AT THE GATE PRIOR TO DEP, ATIS RPTED LOW CEILINGS AND 1 SM VISIBILITY WITH ALL RWYS IN USE. THE BOOK SHOWED RWY 24 AS PRIMARY, ALONG WITH DATA FOR RWY 6. WE BRIEFED A RWY 24 TKOF WITH RVR TOUCHDOWN 6, MID RVR 6, ROLLOUT RVR 6 AS MINIMUMS. WE THEN BRIEFED OUR PLAN FOR A RETURN TO THE ARPT, IF NECESSARY, AND SET THE RADIOS FOR THE ILS RWY 6, WHICH PROVIDED LOWEST MINIMUMS. PRIOR TO OUR CALL FOR TAXI, AN ACFT AHEAD OF US REQUESTED RWY 6. OUR BOOK SHOWED A HIGHER RWY LIMITED WT FOR RWY 6 (A BETTER SAFETY MARGIN), SO WHEN ATC ASKED FOR OUR RWY PREFERENCE, WE REQUESTED AND WERE CLRED TO RWY 6. WE DID NOT CHK RWY 6 TKOF MINIMUMS. THERE WAS PATCHY FOG ON THE ARPT, BUT BOTH TXWY VISIBILITY AND RWY VISIBILITY WERE VERY GOOD. WHILE TAXIING, I RECALL HEARING ATC BROADCAST SOME FAIRLY HIGH RVR'S WITHOUT A REQUEST FOR AN ACKNOWLEDGEMENT. AT THE TIME, I RECALLED THE RVR TOUCHDOWN 6, MID RVR 6, ROLLOUT RVR 6 RVR WE HAD BRIEFED FOR RWY 24, AND WITH OUR PRESENT GOOD VISIBILITY, PRESSED ON, MAKING AN UNEVENTFUL TKOF AND DEP. IT WAS NOT UNTIL SOME 5 HRS AND 2 LEGS AFTER WHEN PREPARING FOR ANOTHER DEP THAT THE THOUGHT OCCURRED TO ME THAT WE NEVER SPECIFICALLY CHKED BHM RWY 6 DEP MINIMUMS. WHEN I CHKED, I FOUND A REQUIREMENT FOR AN RVR OF 50 OR 1 SM VISIBILITY. WE HAD AN ATIS RPTED VISIBILITY OF 1 SM, BUT SINCE I CANNOT RECALL THE SPECIFIC RVR RPTED DURING TAXI OUT, WE MAY HAVE DEPARTED RWY 6 WITH LESS THAN MINIMUM VISIBILITY.

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.