Narrative:

Made takeoff from runway 5 at tri below takeoff minimums. Runway 23 RVR 1000 ft touchdown zone and 12000 ft rollout. Runway 23 was active. Although only 600 ft was required, I requested runway 5 thinking that visibility would be better. I assumed that runway 5 takeoff minimums were same as runway 23. Got to runway 5 and tower advised that runway 5 RVR now 800 ft touchdown zone and 1000 rollout. Tower cleared us for takeoff. Because of low visibility during taxi, the before takeoff checklist did not flow very smoothly. I was concentrating on taxiing so much the checklist got hurried at end as we reached the runway. When I finally thought to confirm the takeoff minimums for the new runway, tower had already cleared us for takeoff we misread the runway 5 RVR 500 ft as 500 ft and not 5000 ft and we accepted the takeoff clearance. As soon as we were airborne we realized our error. The combination of uncertainty about reduced visual RVR requirements, the hurried checklist, and the concentration necessary to taxi caused a huge error in judgement. While it may seem impossible to interpret runway 5 to minimum 500 ft as 500 ft and not 5000 ft when we all know the lowest RVR anywhere is 600 ft. That is exactly what we did. We saw 500 ft -- 1 1/4 and we believed 500 ft is what we needed. Next time I'll slow down and think before I act.

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Original NASA ASRS Text

Title: FLC OF AN LTT TOOK OFF BELOW PUBLISHED MINIMUMS.

Narrative: MADE TKOF FROM RWY 5 AT TRI BELOW TKOF MINIMUMS. RWY 23 RVR 1000 FT TOUCHDOWN ZONE AND 12000 FT ROLLOUT. RWY 23 WAS ACTIVE. ALTHOUGH ONLY 600 FT WAS REQUIRED, I REQUESTED RWY 5 THINKING THAT VISIBILITY WOULD BE BETTER. I ASSUMED THAT RWY 5 TKOF MINIMUMS WERE SAME AS RWY 23. GOT TO RWY 5 AND TWR ADVISED THAT RWY 5 RVR NOW 800 FT TOUCHDOWN ZONE AND 1000 ROLLOUT. TWR CLRED US FOR TKOF. BECAUSE OF LOW VISIBILITY DURING TAXI, THE BEFORE TKOF CHKLIST DID NOT FLOW VERY SMOOTHLY. I WAS CONCENTRATING ON TAXIING SO MUCH THE CHKLIST GOT HURRIED AT END AS WE REACHED THE RWY. WHEN I FINALLY THOUGHT TO CONFIRM THE TKOF MINIMUMS FOR THE NEW RWY, TWR HAD ALREADY CLRED US FOR TKOF WE MISREAD THE RWY 5 RVR 500 FT AS 500 FT AND NOT 5000 FT AND WE ACCEPTED THE TKOF CLRNC. AS SOON AS WE WERE AIRBORNE WE REALIZED OUR ERROR. THE COMBINATION OF UNCERTAINTY ABOUT REDUCED VISUAL RVR REQUIREMENTS, THE HURRIED CHKLIST, AND THE CONCENTRATION NECESSARY TO TAXI CAUSED A HUGE ERROR IN JUDGEMENT. WHILE IT MAY SEEM IMPOSSIBLE TO INTERPRET RWY 5 TO MINIMUM 500 FT AS 500 FT AND NOT 5000 FT WHEN WE ALL KNOW THE LOWEST RVR ANYWHERE IS 600 FT. THAT IS EXACTLY WHAT WE DID. WE SAW 500 FT -- 1 1/4 AND WE BELIEVED 500 FT IS WHAT WE NEEDED. NEXT TIME I'LL SLOW DOWN AND THINK BEFORE I ACT.

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.