NASA Center: Marshall Space Flight Center
Public Release Year: 1979
Reference Number: MSFC-SO-43
Category: Public Safety
Origin: Apollo Program
Plane's movement through air creates at each wing tip a vortex a turbulent wind moving in a circular pattern like an air whirlpool. Large aircraft, such as commercial aircraft produce powerful vortices which can be hazardous to small planes following closely behind. For this reason, the FAA requires a five-mile spacing between large and small aircraft approaching a runway to allow time for vortices to dissipate. With an eye towards reducing spacing requirements while assuring lightplane safety, the Department of Transportation used the Laser Doppler Velocimeter. LDV produces valuable information which enables airport controllers to determine when it is safe to land. LDV has application beyond wake turbulence research. It can be used as a meteorological tool to measure winds aloft with greater accuracy than weather balloons or as a means of measuring smoke stack pollution dispersion patterns.
Page Number in Published book: 57
Manufacturer: DEPARTMENT OF TRANSPORTATION