# Modeling and Analysis of Noise Emission Using Data from Flight Simulators
## 4 Conclusions  
An analysis was conducted to assess the impact of selected factors on noise and gaseous emissions in currently adapted noise-abatement procedures.  
Noise measured in aviation can be expressed using various metrics, which can be classified as maximum-based, exposure-based, and an overall cumulative indicator. For the purpose of this research, the analysis focused primarily on the Sound Exposure Level (SEL) indicator, which takes into account both the maximum sound intensity level, as well as the duration of noise exposure during a single aircraft event, such as a single aircraft overflight. For the purpose of this study, SEL is a sufficiently advanced indicator of noise exposure; however, in practical applications, more complex indicators shall be considered.  
The presented MATLAB environment for the noise and gaseous emissions calculation is of a simplified nature, although it was created in accordance with recommendations for real noise modeling software provided in ECAC.CEAC Doc 29. The main novelty and advantage over commonly used noise engines is the use of flight trajectory data acquired from flight simulators instead of trajectories from Flight Data Recorders, which can be costly, or trajectories synthesized using procedural steps and motion equations.  
Section 3 provides a broad description of some of the parameters that can be implemented in the software, which can aid in assessing the capabilities of noise-abatement procedures in given conditions or in comparative analysis of various solutions. The parameters were described using an example of a reduced take-off thrust scenario; however, the analysis was performed for all the examined factors.  
This enabled the global and local trade-off analysis between the noise and gaseous emissions reduction to be performed with the aid of trade-off charts. The charts presented as Figures 9 and 10 provide a holistic overview and indicate which factors influence the emissions in the most beneficial way, as well as which of the two procedures (NADP1 or NADP2) is more effective at noise reduction, as well as \(CO_{2}\) emissions reductions.  
The main finding from the trade-off analysis is that aerodrome operators may benefit from the locally oriented approach in assessing the best noise-abatement procedure having given the location of the most noise-sensitive areas. It is however important to note that usually Standard Instrument Departures (SIDs) are equally significant for efficient noise reduction by means of laterally vectoring aircraft alongside the track that minimizes the time or the ground run over noise-sensitive areas.  
Considering the fact that the global trade-off chart indicates that neither NADP1 nor NADP2 can minimize both noise and gaseous emissions regardless of the analyzed scenario, it implies that an optimal noise-abatement procedure exists, which can maximize the possible emissions reduction. Further research into the issue of aircraft's emissions might include the noise-abatement procedure optimization or developing the existing noise model to integrate the effect of the terrain surrounding the airfield or flying with a non-zero bank angle along a curved trajectory. Additionally, the possibility of modeling with more complex noise indicators may be examined. This should require abundant data of simulated flight trajectories, which would allow for a calculation of time-averaged cumulative noise metrics that are more common in real applications of airport noise mapping.  
Conceptualization, F.T.; methodology, F.T.; software, F.T.; validation, F.T.; formal analysis, F.T. and P.R.; investigation, F.T.; resources, F.T. and P.R.; data curation, F.T.; writing--original draft preparation, F.T.; writing--review and editing, P.R.; visualization, F.T.; supervision, P.R.; project administration, P.R.; funding acquisition, P.R. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.