## 6 Conclusions and Future Work  
The study investigates the efficiency of the noise control approach for a notional supersonic civil aircraft at takeoff, based on the implementation of VNRS with thrust control. Noise levels are computed with a decoupling approach, wherein the engine noise data and the flight trajectory are calculated independently. For the purposes of this study, experimental data of static noise tests (one-third octave spectra over a range of azimuthal angles for different thrusts of the subsonic donor engine) were used to obtain the powerplant noise levels of the aircraft at all points of its takeoff trajectory. However, the data can be obtained numerically as well, based on the semi-empirical models of different engine noise sources (jet noise, fan noise, core noise, etc.) An in-house code for optimization of high-lift device deflection angles to minimize the certification noise levels of subsonic aircraft was modified to allow for automatic thrust control. The modified code was used to compute the standard and advanced (i.e., with variable thrust) takeoff procedures and for optimization of thrust control for the certification noise at the lateral and flyover measurement points. It is shown that implementation of such a VNRS for supersonic civil aircraft could lead to the reduction in the certification noise levels at the lateral (on the sideline at 450 m) and flyover measurement points by about four EPNdB. This noise reduction is a result of an intricate balance between noise reduction at the lateral point due to lateral attenuation and noise increase at the flyover point due to a decrease in flight altitude over that point. The effect of VNRS on noise levels for the other allowable position of the lateral certification point (on the extended runway centerline) is considered for the first time. Its consideration in the context of SST noise studies is motivated by the concept of SST with turboprop buster engines [4]. However, it is also expected that the efforts on VNRS development for supersonic aircraft, such as the automatic control of high-lift devices, will lead to wider implementation of VNRS for subsonic aircraft as well, including propeller-driven aircraft. It is highlighted that additional clarity from regulatory authorities on the definition of the lateral certification point on the extended runway centerline may be needed. It is obtained that the reduction in the cumulative certification noise at the flyover and lateral point due to the VNRS is larger by 0.8 EPNdB for the position of the lateral certification point on the sideline than for the position on the extended runway centerline. It is likely that the difference is caused by the effect of lateral attenuation for the former case. However, the thrust control used for noise calculation at the advanced takeoff procedure was the same for both positions of the lateral certification points, and thus it was not optimized for noise abatement at the lateral point along the extended runway centerline. Optimization of the advanced takeoff procedure for this position will lead to further noise reduction at the point, so that the cumulative noise reduction for optimized trajectories will be similar for both positions of the lateral certification point. Such a study can be performed when more regulatory certainty on the certification point in the context of VNRS implementation becomes available. The current status of the results of the study lead to the tentative conclusion that position K\({}_{2}\) for the lateral certification point provides lesser certification noise levels for SST. Conceptualization, V.K. ; methodology, I.B. and S.V. ; software, S.V. ; validation, S.V. ; formal analysis, V.K. ; investigation, I.B. ; resources, V.K. ; data curation, I.B. and V.K. ; writing--original draft preparation, I.B. ; supervision, V.K. ; project administration, V.K. ; funding acquisition, V.K. All authors have read and agreed to the published version of the manuscript. This study was partially supported by the Russian Science Foundation (Grant no.