A psychophysical evaluation of the accuracy of shape discrimination as an aircraft landing aid.

Abstract

Pilots flying into unfamiliar airports may find it difficult to judge correctly the proper glide angle when landing. Several types of landing aids are now in use to eliminate this problem; however, they are typically expensive to install and maintain. A possible solution to this problem is the replacement of runway centerline striping with painted diamonds. Changes in the projected shape of the diamonds could provide glide angle information. It was the purpose of this study to evaluate the accuracy possible in detecting glide angle using this method. The just-noticeable difference between a square and a diamond shape was determined. This ratio was found to be 1.049/1.00 for the upper just noticeable difference and .945/1.00 for the lower just noticeable difference. This finding indicates that, if discrimination in the real world approaches this accuracy, deviations of approximately .17° above or below glide slope are detectable.