Establishment Criteria for Visual Approach Slope Indicator (VASI).

This report develops revised establishment and discontinuance criteria for Visual Approach Slope Indicator VASI which provide Visual Flight Rules VFR guidance only. Criteria are based upon detailed benefitcost methodology. This approach takes into account the number of aircraft landings by user class with variations depending upon whether or not the runway is equipped with an Instrument Landing System. Benefits derived from a VASI were principally in the area of safety which are obtained by improved guidance during final VFR approaches. Revised criteria require that a ratio value be computed for each of the three types of operations air carrier, air taxi, and general aviation including military. The three ratios are then added to obtain a total ratio value, and this is multiplied by the runway utilization to obtain a net ratio value. If this net ratio value is equal to 1 or greater, then the runway is a candidate for a VASI. In the short term, it is estimated that 590 runways now without a VASI will qualify. Over the next ten years, an additional 388 runways are expected to qualify for a VASI. Author