Narrative:

ATIS report of west 2X 1/8 F1 tower reported RVR of 1400. Nonstandard takeoff minimums for runway 27 on the airport diagram states a minimum takeoff RVR of 2400, reported. Several other aircraft inquired about the RVR. After a part 135 operator and another scheduled carrier departed with RVR's of 1600, my copilot and I consulted the operations specifications to read that a nonstandard takeoff minimum could be reduced to 1600 RVR. Reference: our airlines operations specifications, 56 C.(1). We elected to proceed with a takeoff when the RVR attained 1800 with the above-mentioned authority. After the 2 previous aircraft departed, the RVR dropped below 1600 RVR, so we waited till something better was confirmed. FAA is inquiring into the situation thus prompting this report. The part 135 carrier stated (unconfirmed) that he needed 1600 RVR to takeoff, due to his operations specifications. Supplemental information from acn 132773: we consulted our general operations manual, and I decided we (the captain and I) could reduce the RVR to 1600' based on the fact that centerline markings for runway 27 were available. When the tower controller informed us the RVR was 1800, we taxied to runway 27 and took off. After landing at O'hare our final destination, we were informed we had departed below takeoff minimums. The captain and I discussed the gom and length before takeoff, and realize that we misinterpreted the rules in the gom. We did not intentionally violate the far's.

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Original NASA ASRS Text

Title: A NUMBER OF COMMUTER ACFT TKOF FROM SBN WHEN THE RVR IS BELOW TKOF MINIMUMS.

Narrative: ATIS REPORT OF W 2X 1/8 F1 TWR REPORTED RVR OF 1400. NONSTANDARD TKOF MINIMUMS FOR RWY 27 ON THE ARPT DIAGRAM STATES A MINIMUM TKOF RVR OF 2400, REPORTED. SEVERAL OTHER ACFT INQUIRED ABOUT THE RVR. AFTER A PART 135 OPERATOR AND ANOTHER SCHEDULED CARRIER DEPARTED WITH RVR'S OF 1600, MY COPLT AND I CONSULTED THE OPS SPECS TO READ THAT A NONSTANDARD TKOF MINIMUM COULD BE REDUCED TO 1600 RVR. REFERENCE: OUR AIRLINES OPS SPECS, 56 C.(1). WE ELECTED TO PROCEED WITH A TKOF WHEN THE RVR ATTAINED 1800 WITH THE ABOVE-MENTIONED AUTHORITY. AFTER THE 2 PREVIOUS ACFT DEPARTED, THE RVR DROPPED BELOW 1600 RVR, SO WE WAITED TILL SOMETHING BETTER WAS CONFIRMED. FAA IS INQUIRING INTO THE SITUATION THUS PROMPTING THIS REPORT. THE PART 135 CARRIER STATED (UNCONFIRMED) THAT HE NEEDED 1600 RVR TO TKOF, DUE TO HIS OPS SPECS. SUPPLEMENTAL INFORMATION FROM ACN 132773: WE CONSULTED OUR GENERAL OPS MANUAL, AND I DECIDED WE (THE CAPT AND I) COULD REDUCE THE RVR TO 1600' BASED ON THE FACT THAT CENTERLINE MARKINGS FOR RWY 27 WERE AVAILABLE. WHEN THE TWR CTLR INFORMED US THE RVR WAS 1800, WE TAXIED TO RWY 27 AND TOOK OFF. AFTER LNDG AT O'HARE OUR FINAL DEST, WE WERE INFORMED WE HAD DEPARTED BELOW TKOF MINIMUMS. THE CAPT AND I DISCUSSED THE GOM AND LENGTH BEFORE TKOF, AND REALIZE THAT WE MISINTERPRETED THE RULES IN THE GOM. WE DID NOT INTENTIONALLY VIOLATE THE FAR'S.

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.