Narrative:

While on an ILS approach with minimums of 200 ft and RVR of 1800 ft. The WX was reported by ATIS as 800 ft obscured and visibility 1/2 in snow and blowing snow. Approach reported the RVR 1800. After contacting the tower past the final approach fix, the RVR was reported as 1600, rollout 1800. The landing was made with our estimated flight visibility at 1/2 mi. In the above case, a question arose while shooting the approach what the actual flight visibility was for legally making a landing. After reviewing 91.175 concerning flight visibility, it seems the definition on what constitutes the flight visibility should be stated more clearly.

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Original NASA ASRS Text

Title: A CPR LTT JET PLT COMPLAINS ABOUT THE DEFINITIONS CONTAINED IN FAR 91 PT 175 REGARDING FLT VISIBILITY.

Narrative: WHILE ON AN ILS APCH WITH MINIMUMS OF 200 FT AND RVR OF 1800 FT. THE WX WAS RPTED BY ATIS AS 800 FT OBSCURED AND VISIBILITY 1/2 IN SNOW AND BLOWING SNOW. APCH RPTED THE RVR 1800. AFTER CONTACTING THE TWR PAST THE FINAL APCH FIX, THE RVR WAS RPTED AS 1600, ROLLOUT 1800. THE LNDG WAS MADE WITH OUR ESTIMATED FLT VISIBILITY AT 1/2 MI. IN THE ABOVE CASE, A QUESTION AROSE WHILE SHOOTING THE APCH WHAT THE ACTUAL FLT VISIBILITY WAS FOR LEGALLY MAKING A LNDG. AFTER REVIEWING 91.175 CONCERNING FLT VISIBILITY, IT SEEMS THE DEFINITION ON WHAT CONSTITUTES THE FLT VISIBILITY SHOULD BE STATED MORE CLRLY.

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.