Narrative:

On feb/xx/95, I was the captain on a part 121 commercial flight from corpus christi to dfw. After a reduced rest overnight, I dutied in at AM57 local time having had less than 5 hours sleep. As we taxied for takeoff, the visibility was reported as 1/4 mi and patchy fog with 1000 RVR on runway 13. As we reached the departure end of the runway, the tower said the visibility had dropped to 1/8 mi and 800 RVR, but the controller said a new report would come out in a few min. I elected to hold short of the runway and wait for the report. In the meantime, I double checked the departure minimums on the (commercial) chart which showed 2 parameters of takeoff minimums -- 1 that showed standard 1 mi and the other 1/4 mi or 1600 RVR. I knew that my company's standard practice operations specifications allowed me to reduce minimums from the standard 1 mi with certain qualifying conditions, however, when the new WX report came out showing 1/4 mi visibility and 1000 RVR, I asked for and received clearance for takeoff. I made a normal reduced visibility takeoff and the flight proceeded without incident. I relied on my understanding of my company's operations specifications regarding reduced visibility takeoffs rather than getting the book out and making absolutely sure I was in full legal compliance before taking the runway. I feel that fatigue clouded my judgement and affected my decision-making ability in this situation.

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Original NASA ASRS Text

Title: FLC OF AN MDT TOOK OFF BELOW PUBLISHED WX MINIMUMS. (RVR IS CTLING.)

Narrative: ON FEB/XX/95, I WAS THE CAPT ON A PART 121 COMMERCIAL FLT FROM CORPUS CHRISTI TO DFW. AFTER A REDUCED REST OVERNIGHT, I DUTIED IN AT AM57 LCL TIME HAVING HAD LESS THAN 5 HRS SLEEP. AS WE TAXIED FOR TKOF, THE VISIBILITY WAS RPTED AS 1/4 MI AND PATCHY FOG WITH 1000 RVR ON RWY 13. AS WE REACHED THE DEP END OF THE RWY, THE TWR SAID THE VISIBILITY HAD DROPPED TO 1/8 MI AND 800 RVR, BUT THE CTLR SAID A NEW RPT WOULD COME OUT IN A FEW MIN. I ELECTED TO HOLD SHORT OF THE RWY AND WAIT FOR THE RPT. IN THE MEANTIME, I DOUBLE CHKED THE DEP MINIMUMS ON THE (COMMERCIAL) CHART WHICH SHOWED 2 PARAMETERS OF TKOF MINIMUMS -- 1 THAT SHOWED STANDARD 1 MI AND THE OTHER 1/4 MI OR 1600 RVR. I KNEW THAT MY COMPANY'S STANDARD PRACTICE OPS SPECS ALLOWED ME TO REDUCE MINIMUMS FROM THE STANDARD 1 MI WITH CERTAIN QUALIFYING CONDITIONS, HOWEVER, WHEN THE NEW WX RPT CAME OUT SHOWING 1/4 MI VISIBILITY AND 1000 RVR, I ASKED FOR AND RECEIVED CLRNC FOR TKOF. I MADE A NORMAL REDUCED VISIBILITY TKOF AND THE FLT PROCEEDED WITHOUT INCIDENT. I RELIED ON MY UNDERSTANDING OF MY COMPANY'S OPS SPECS REGARDING REDUCED VISIBILITY TKOFS RATHER THAN GETTING THE BOOK OUT AND MAKING ABSOLUTELY SURE I WAS IN FULL LEGAL COMPLIANCE BEFORE TAKING THE RWY. I FEEL THAT FATIGUE CLOUDED MY JUDGEMENT AND AFFECTED MY DECISION-MAKING ABILITY IN THIS SIT.

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.