Multi-parametric evaluation method of aircraft wake vortex encounter safety in cruise phase

The response mechanism of aircraft after encountering wake vortices was analyzed. Considering the factors such as roll damping characteristics and handling qualities of aircraft, the calculation model for the roll angular acceleration of aircraft was constructed. Due to the change in the flight path and attitude after wake vortex encounters, several disturbance parameters were selected to evaluate the safety of wake vortex encounters, and the calculation model for aircraft dynamics parameters was built. For the determination of the acceptable safety level of wake vortex encounters, the computation data of the disturbance parameters for wake vortex encounters of aircraft combinations at medium and low altitudes were obtained on the basis of the current domestic standard of wake separation. The evolutionary characteristics of the flow fields of wake vortices at high altitudes were analyzed, the wake safety separation at high altitudes was studied, and the influence of different factors on flight safety was analyzed. Research results show that compared with the results at medium and low altitudes, the flow fields of wake vortices at high altitudes are characterized by larger initial strength and duration. Beyond the flight altitude of 9 000 m, the speed of wake vortex dissipation increases with the rise in height. When the leading aircraft is a super heavy aircraft or heavy aircraft, flight safety cannot be guaranteed by current wake separation, and the safety separation should increase by 1.4-2.1 km. When the flight altitude is beyond 13 800 and 14 400 m, the severity of wake vortex encounters reduces. When the leading aircraft is a general heavy aircraft, the wake safety separation can reduces by 1.5 km to improve airspace utilization efficiency. In the case of a medium-size leading aircraft, the safety of wake vortex encounters is high, but due to the limitation of the minimum radar separation, the distance between the leading and following aircraft cannot further reduce. A lower flight speed of the following aircraft is accompanied by more serious wake vortex encounters. When the initial roll bank angle of the following aircraft raises from 0 to 10°, the safety separation of wake vortices raises by 1.3 km, an increase of about 8.61%. It can be seen that the use of multiple disturbance parameters is effective in evaluating the severity of high-altitude wake vortex encounters. 4 tabs, 15 figs, 30 refs.