Europe is targeting fuel burn and emission reductions of 20-30% from 2014 levels for airliners entering service in the 2025-35 time frame, through increased integration of propulsion, structures and systems to be demonstrated under the proposed Clean Sky 2 research program.

Planned to get under way this year as a follow-on to the current Clean Sky public-private partnership, Clean Sky 2 is focused on large-scale integrated demonstrations to raise the maturity of technologies aimed at the next generation ofcommercial aircraft, regional airliners, business jets and rotorcraft.

Under Clean Sky 2—which is awaiting political approval—the Large Passenger Aircraft (LPA) program led by Airbus would include demonstrators for airframe-engine integration, hybrid laminar flow control, increased integration of cabin systemsand structures, and next-generation cockpit, avionics and all-electrical systems.

Set to conclude in 2023, Clean Sky 2 is budgeted at €4.05 billion ($5.5 billion), a substantial increase from the €1.6 billion budget for Clean Sky, set to end in 2017. The European Union would provide €1.8 billion of the funding—up from €800 million for Clean Sky 1—and industry the rest.

The largest part of the LPA Innovative Aircraft Demonstrator Program (IADP), at €560 million, would cover flight demonstration of an open-rotor engine by 2020, a hybrid laminar-flow control wing by 2023 and possible “X-plane” demonstrators for radical aircraft configurations.

Ground tests of the Snecma geared counter-rotating open rotor are planned for 2015 under Clean Sky 1, but delays pushed flight tests of the engine mounted on the rear fuselage of a modified Airbus A340-600 into Clean Sky 2. The IADP includes demonstration of an “engine-integration-driven” rear fuselage.

Flight tests of natural laminar-flow wing sections are planned on a modified A340-300 in 2015 under Clean Sky 1. This aircraft will have the outer wing panels replaced with lower-sweep, laminar-flow sections using two different design concepts.Under Clean Sky 2, work will expand to hybrid laminar-flow control (HLFC), where suction or blowing is used to maintain smooth drag-reducing airflow. Plans include flight tests of a large HLFC test specimen and high-speed demonstrationof an HLFC wing.

The second demonstrator platform planned under the LPA IADP, budgeted at €290 million, is focused on increased physical integration of the fuselage, cabin and cargo systems and structures. The third platform, budgeted at €230 million, includescockpit, avionics and all-electric systems demos.

The overall goals of Clean Sky 2 are to reduce fuel burn and carbon dioxide emissions by 20-30% from 2014 levels for new narrowbody aircraft entering service in 2025-30, and in 2030-35 for new widebody airliners. Nitrogen oxide emissions are to be reduced 20-40% and the noise footprint by up to 75%.

The re-engined narrowbodies under development by Airbus and Boeing offer up to 15% fuel-burn reductions from the models now in production, while all-new aircraft like Bombardier’s CSeries promise reductions up to 20% over 110-160-seat airlinerscurrently in use. These aircraft will enter service around the middle of this decade.

Under the LPA program, advanced engines and airframe integration are expected to contribute 15-20% of the targeted reductions; next-generation cockpit, navigation and avionics 8-10%; laminar flow 6-9%; fuselage, cabin and cargo integration5-10%; and innovative flight operations another 5-10%.