Formation Airdrop Scaling Effects on Aircraft Wake Vortex Formation and Interaction

A parametric model for location and strength of aircraft wake vortices is used to determine the potential for hazardous wake vortex/personnel interaction for different operational, environmental, and formation geometry parameters across two scaling studies. In the first study, 729 variations of a four-aircraft formation resulted in 39 geometries with potential for adverse jumper-wake vortex interactions. A second six-aircraft study, with finer variations in element-to-element spacing, indicated adverse interactions in 575 of the 1,224 variations considered. In both experiments, the formations with adverse interactions included nontrival yet predictable combinations of lateral and longitudinal spacing, airspeed, and crosswind, with a noticeable lack of sensitivity to aircraft weight. These results can lead to more flexible formation airdrop planning guidelines by identifying the combinations of conditions that lead to adverse wake vortex encounters.