1. The process started with a detailed study and a comprehensive examination of the current inventory of measures, noise and objectives and the expected evolution with several scenarios, the assessment of new measures and the conclusions;
2. Considering the acoustical description, modelling and indicators, the study was searching for the benefits of operating restrictions and characterised the global noise in terms of number of people exposed and exposed areas to each Lden and Lnight levels (Figure 2);
![](/fileadmin/_processed_/0/7/csm_3.4.1.5_Barcelona_case_study_1_people_affected_2_881966bc0a.png)
Figure 2. Areas and the number of people affected by aircraft noise
3. In-depth analysis of marginally compliant hour-by-hour operations at Barcelona Airport was performed to characterise the noise from the noisiest aircraft with its influence on general noise;
4. After an in-depth study of the current situation, it was necessary to characterise the future and answer the questions on what would happen to the airport's development in the next 5-7 years, which is the noise action programme, which are the fleets, etc.;
5. The most important part of the study was the assessment of "additional" measures. Firstly, the measures were defined (operational restriction measures) and assessed from an acoustic point of view. Finally, a cost-benefit analysis was carried out;
6. The acoustic assessment of the additional measures was carried out for three different scenarios of implementation, always comparing noise contours with and without marginally compliant aircraft in terms of Ldenand Lnight and areas and people exposed to each level (see one scenario in Figure 3; download the full study for the three scenarios). The results were not enough to implement a particular measure (restriction), and the study was complemented with in-depth analysis in some selected points with more populated areas;
![](/fileadmin/_processed_/9/d/csm_3.4.1.5_Barcelona_case_study_1_scenario_2_5ba6811e1e.png)
Figure 3. One of three scenarios comparing noise contours with and without marginally compliant aircraft in terms of Lden and areas and people exposed to each level (download the full study for other scenarios)
7. The outcomes of this final assessment showed clear benefits in terms of the number of people affected by noise annoyance (under noise insulated levels) and less awakeness due to the aircraft noise;
8. The cost/benefit analysis showed only one airline affected at significant levels;
9. The study was first presented to the GTTR and after its approval started the legal process to implement the operating restrictions. The restrictions were approved by the Resolution of 31 May 2011 of the Spanish Air Safety Agency (AESA);
10. The implementation process has been observed and controlled by the aviation authorities.