Assessment of the Wake-Vortex Proximity to Landing Aircraft Exploiting Field Measurements

This paper examines possible wake-vortex encounters by analyzing light detection and ranging (LIDAR) field measurements conducted by DLR, German Aerospace Center and NASA at major international airports (Dallas, Denver, Frankfurt, Memphis, and Munich) comprising 8056 aircraft landings. The applied aircraft separations are analyzed, depending on the involved aircraft types and compared to the International Civil Aviation Organization and recategorization separation standards. Furthermore, the distances between the wake generated by the leading aircraft and the follower are evaluated. The results reveal that, in at least 3.7% of the landings in which the measured vortices are generated in an altitude below 50 m, the luff vortex remains within a distance of 50 m to the follower within a temporal buffer of ±10  s of flyby. In only three landings, the encounters exceed a roll-control ratio of 0.2: a limit beneath which encounters are considered acceptable by pilots.