Abstract

Wind shear, the sudden and violent change of wind direction near the ground has been a contributing factor in at least 28 aviation accidents and incidents involving commercial aircraft since 1964, including more than 600 fatalities. The hazard due to wind shear on a flying aircraft is characterized by the F-factor hazard index.¹ As part of the NASA/FAA Integrated Wind Shear Program, and NASA'S Terminal Area Productivity Program Lockheed designed and built in cooperation with NASA Langley Research Center (along with subcontractors United Technology Optical Systems, Coherent Technologies, Inc., and Lassen Research) two Coherent Lidar Airborne Shear Sensors. These systems have the capability to look ahead of an aircraft 2 to 4 km in clear weather and measure the line-of-sight wind velocity with an accuracy of 1 m/s.

© 1995 Optical Society of America