^{Figure 1. Cluj-Napoca Airport and its surrounding areas (source: ANIMA Workshop, September 2020)}

Cluj-Napoca is the largest urban centre of Transylvania. Cluj Avram Iancu Airport is a rapidly growing airport, located in the North-Western part of Romania, with over 2.5 million passengers in 2017. The airport is currently undergoing a major development in anticipation of future growth, with a new runway being built in two phases to accommodate larger aircraft.

The airport provides up to 45 domestic and international destinations to 21 countries from Europe and the Middle East.

Noise regulations

The Environmental Noise Directive (END) was transposed into the National legislative framework in 2005 and was continuously updated ever since. For Cluj Airport, the Strategic Noise Maps (SNMs) development and Action Plans is not mandatory as a 'major airport'. However, the airport has developed Strategic Noise Maps and Noise Action Plans (NAPs) to manage noise problems, following ICAO Balanced Approach. Current Noise Action Plans (2018) consider noise mitigation measures for short-term and long-term periods. Additionally, the airport recommends the use of NADP1 for certain runways.

There are no operational restrictions on noise considered within the 2018 Noise Action Plan, apart from several aircraft types allowed to operate in compliance with 'noise at source' requirements. However, the latest Noise Action Plan recommends reducing the night time flights as much as possible and redirecting aircraft to fly over less populated areas whenever possible.

This case study investigates the use of preferential runways and night-time flight restrictions at the airport, in order to avoid overflying Cluj-Napoca city and, therefore, to avoid this highly populated area. The intervention of this case study considers the implementation of an intervention focused on operational noise abatement procedures.

The stakeholders involved in the intervention include airport operators and several other relevant stakeholders such as the Air Navigation Service Provider, the Civil Aviation Authority, aircraft operators, Environmental and Government organisations and other interested parties.

Objective

This intervention's objective was to identify the best scenario related to the traffic distribution and investigate the relationship with the noise exposure of the population from Cluj-Napoca city, as it increased significantly after the new runway was built (2013) and developed between 2013 and 2017.

^{Figure 2. Yellow part – original runway. Blue part – new runway which started operating in 2013. Red part – the forecasted extension of the new runway (encountered environmental problems due to the necessity of a river deviation) (source: Cluj Airport)}

Approach

Considering the ICAO Balanced Approach Regulation and the Environmental Noise Directive, in 2013 Cluj Airport developed Strategic Noise Maps and a Noise Action Plan (2014), while taking into account the opinions and the recommendations of experts, forecasts of the future expected air traffic. One primary focus was also to ensure transparent communication with the communities.

1. Due to the airport's fast growth, the first stage of a new runway was built in 2013 and started operating (see Figure 2). The newly built runway was made in a way that allows more efficient distribution of fly-overs across communities, especially during the night-time;
2. Establishing preferential runways for take-offs and landings to avoid overflying Cluj-Napoca city was proposed in the first Noise Action Plan in 2014, considering different stakeholders' points of view;
3. Experts proposed a solution – establishing smaller percentages of flights distributed above Cluj-Napoca city, together with an imposed maximum number of aircraft movements at night. From the economic point of view, it is expected that this intervention would increase in operating costs for the airlines and will reduce the number of flights to Cluj Airport either by cutting out certain destinations or by reducing the actual number of flights;
4. Additionally, the problem is assumed to decrease in significance when new quieter aircraft generations will become operational, but also when the second runway segment will be built, as this might support the implementation of noise respite;
5. The implementation of the proposed intervention was not fully completed until 2017 when the airport representatives had commissioned a new noise study for the 2018 Noise Action Plan;
6. The airport and the whole community started to understand more about the importance of noise issues within sustainable development. This perception resulted from several interviews with important stakeholders during the development of this study and some local newspaper articles;
7. The new proposed distribution within the intervention has revealed a significant reduction (over ten times) in the number of people exposed to the values of the L_night over the long-term target of 50 dB and 60% decrease of the number of people exposed to L_night exceeding 60 dB.

The proposed intervention to use preferential runways for arrivals and departures appeared to be an effective solution for noise mitigation, in relation to the air traffic forecast for the next five years (2017-2022). Several other contributing factors, like the extension of the runway, the use of next generations of quieter aircraft and the use of specific NADP1/ NADP2 procedures, are considered to support the noise mitigation efforts in the area of Cluj-Napoca city. Understanding stakeholders' responsibilities and developing long-term monitoring strategies are considered to be still challenging because the financial and economic impact are not properly determined yet.