Forward Scatter Meter Measurements of Slant Visual Range.
Air Force surveys in geophysics,
AIR FORCE GEOPHYSICS LAB HANSCOM AFB MASS
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The potential for remote tower measurements of point visibility in the determination of slant range visibility for aircraft landing operations was explored through analysis of data collected at the Air Force Geophysics Laboratory Weather Test Facility at Otis AFB, Massachusetts. This report described initial experiments that deal with an analysis of the small scale variability of extinction coefficient in time and space. Data from two instrumented towers spaced 1500 ft apart were classified for investigation of the horizontal variability of visibility at elevations up to 100 ft and space-time variability for lag periods from 0 to 10 minutes. The preliminary tests give additional evidence that the runway visual range RVR measurements alone often are not representative of pilot visibility during approach and touchdown. Remote measurements of visibility using either a 50-ft or 100-ft instrumented tower would add significantly to the real safety of see-to-land operations under conditions of Categories I, II, and IIIa through an improved description of conditions related to airfield visibility. Author