Narrative:

Field WX decreased from VFR to a low visibility condition due to ground fog. Just prior to taxi with the tower, reported 1/4 mi and RVR runway 4 reported going from +4000 ft to 800 ft/600 ft. As we went into position (with over 1000 ft of visibility in bright sun), we received takeoff clearance. During takeoff roll, another aircraft refused takeoff due to a reported RVR now of 800 ft/500 ft (below our limits). I did not hear or acknowledge any further loss of visibility prior to takeoff. Although the first officer who was doing IOE training with me, and making radio calls, feels as though he might have cut the tower's last report off when he acknowledged the 'cleared for takeoff.'

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Original NASA ASRS Text

Title: MULTIPLE VARIABLE RVR RPTS VERY CLOSE TO THE MINIMUM REQUIRED RAISES THE QUESTION OF WHETHER OR NOT A TKOF WAS MADE BELOW THE AUTH MINIMUM VISIBILITY. A BLOCKED RADIO XMISSION MAY HAVE BEEN AN ISSUE.

Narrative: FIELD WX DECREASED FROM VFR TO A LOW VISIBILITY CONDITION DUE TO GND FOG. JUST PRIOR TO TAXI WITH THE TWR, RPTED 1/4 MI AND RVR RWY 4 RPTED GOING FROM +4000 FT TO 800 FT/600 FT. AS WE WENT INTO POS (WITH OVER 1000 FT OF VISIBILITY IN BRIGHT SUN), WE RECEIVED TKOF CLRNC. DURING TKOF ROLL, ANOTHER ACFT REFUSED TKOF DUE TO A RPTED RVR NOW OF 800 FT/500 FT (BELOW OUR LIMITS). I DID NOT HEAR OR ACKNOWLEDGE ANY FURTHER LOSS OF VISIBILITY PRIOR TO TKOF. ALTHOUGH THE FO WHO WAS DOING IOE TRAINING WITH ME, AND MAKING RADIO CALLS, FEELS AS THOUGH HE MIGHT HAVE CUT THE TWR'S LAST RPT OFF WHEN HE ACKNOWLEDGED THE 'CLRED FOR TKOF.'

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.