Flight Demonstration of an Airborne Turbulence Detection System

Abstract

Air turbulence is the most significant cause of aviation accidents. As a way to reduce the number of such accidents, JAXA has developed the onboard air turbulence detection system based on Coherent Doppler LIDAR (CDL). The flight experiment with a small jet plane measured and compared how the aerosol particle number concentrations responded to backscatter coefficient and the maximum observation range according to altitude. The flight experiment with a large jet plane measured the maximum observation range and the airspeed measurement accuracy at various altitudes. Although we were able to verify that the observation distance was sufficient to provide information for go-around judgement to the pilot during landing approach, the effectiveness of the turbulence induced accident prevention is likely to be limited because of mostly short observation distances at high altitudes. However, the results indicated the errors between the airspeeds measured by CDL, by the Pitot tube and by the speed-course method were quite small. This suggests the airspeed measurement by the CDL can be used as the true airspeed sensor and remote sensor for the gust alleviation control.