Fourteen European aerospace companies, including Eurocopter and Dassault, have signed a letter supporting the proposed “Clean Sky 2” Joint Technology Initiative (JTI). The seven-year, €3.6 billion ($4.8 billion) program is a follow-on to the current Clean Sky JTI funded by the EU and the industry.

Eurocopter announced it will lead a “large-scale compound helicopter demonstrator” project under Clean Sky 2. It would build on the expertise gained with the existing X3 and optimize it for a lower environmental impact, notably in terms of noise. The concept already cuts fuel burn by 20 to 30 percent, Eurocopter claims.

The helicopter manufacturer wants to “evaluate technologies and reduce risk” before greenlighting the development of a commercial aircraft. Preliminary studies would start in 2014, leading to flight tests in 2019. This would overlap with Clean Sky, which is scheduled to end in 2017.

Meanwhile, Dassault said that Clean Sky 2 will “build a bridge” toward the “Flightpath 2050” goals, which includes the reduction of aircraft CO2 emissions by 75 percent, NOx by 90 percent and noise by 65 percent per flight.