New technology

The aviation industry is evolving into new areas, with existing and new start-up companies investing heavily in novel technology. In addition to recent developments of electric and hybrid engines, ideas to enhance urban mobility have also emerged including fully autonomous aircraft that can provide rapid point-to-point connectivity. New aircraft concepts and innovative types of operations have already applied for certification by EASA. These include the redesign of conventional aircraft as well as innovative electrical vertical take-off and landing (VTOL) aircraft. While the traditional noise certification procedure may be appropriate for the first category, drones and VTOL aircraft are more of a challenge. Based on an EASA Opinion, the European Commission is currently finalising proposals for noise requirements for drones that weigh less than 25 kg.

While these novel technologies bring new challenges, they also represent new opportunities to draw on a wider pool of expertise and innovative approaches from other non-aviation sectors to address the sector’s environmental challenges. An in-depth life cycle analysis will be required to assess the environmental impacts of these new concepts in comparison to conventional aircraft. EASA is working closely with applicants to assess the environmental characteristics of these products, and put in place appropriate certification requirements. This will need to take into account new aircraft designs, required infrastructure and their operational characteristics which potentially brings aviation noise much closer to EU citizens [31].

Hybrid and electric aircraft
Various European companies, such as Pipistrel, are currently developing electric power plants for aircraft. The electricity can be generated through a variety of methods including batteries, solar cells, ultracapacitors and fuel cells. In this case, the conventional engine is replaced by a hybrid or electric engine with similar performance. An evaluation of the conventional noise requirements and limits for these types of products will need to be performed.

Urban mobility - Air taxis and vertical take-off and landing (VTOL) aircraft
The number of active projects in this area has increased significantly over the last few years, such as Volocopter and Lilium. Different concepts have emerged with nonconventional designs. Specific studies of the design technologies, and operational procedures close to large populations, will need to be performed in order to identify appropriate noise certification requirements.

Drones
An Unmanned Aerial Vehicle (UAV), also known as a drone, is an aircraft without an onboard human pilot. UAVs are a component of an Unmanned Aircraft System (UAS) that includes a UAV, a ground-based controller and a system of communications between the two. There is a wide range of UAVs ranging from light and simple to heavy and complex aircraft, which operate with various degrees of autonomy and a diverse set of missions.

 

Clean Sky
The Clean Sky 2 initiative (2014-2024), part of the EU Horizon 2020 programme, is a Joint Undertaking of the European Commission and the European aeronautics industry [32]. It builds on the original Clean Sky 1 programme (2008-2017), and contributes towards achieving the ‘Flightpath 2050’ environmental objectives set out by the Advisory Council for Aviation Research in Europe [33]. Bringing together the aeronautics industry, small and medium sized enterprises, research centres and academia to drive forward innovative results, Clean Sky 2 also strengthens European aero-industry collaboration, global leadership and competitiveness. Clean Sky 2 has a total budget of €4 billion, and currently contains over 600 unique entities from 27 countries.

Clean Sky 1 envisioned technologies and procedures that would reduce CO2 emissions per passenger kilometre by 75%, NOX emissions by 90%, and perceived noise by 65% relative to the capabilities of a typical new aircraft in the year 2000. The objectives of Clean Sky 2 are to reduce CO2, NOX and noise emissions by 20 to 30% compared to “state-of-the-art” aircraft entering into service as from 2014.

Clean Sky 2 expects to develop innovative, cutting-edge technologies for more aerodynamic wings, advanced and lighter structures, more efficient engines including the emerging field of hybridization and electrification, advanced control, actuation and guidance systems (including increased digitization), brand-new aircraft configurations, and a more sustainable aircraft lifecycle. The scope of the programme includes large, regional, and commuter aircraft, and rotorcraft.

The Programme aims to accelerate the introduction of new technology in the 2025-2035 timeframe. By 2050, 75% of the world’s fleet now in service (or on order) will be replaced by aircraft that can deploy Clean Sky 2 technologies. The direct economic benefits are estimated at €350-€400 billion and the associated indirect benefits of the order of €400 billion. Clean Sky 2 technologies are expected to bring a potential saving of 4 billion tonnes of CO2 between 2025 and 2050. This is in addition to approximately 3 billion tonnes of CO2 emissions savings that Clean Sky 1 should deliver [34].