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Optimisation for Low Environmental Noise Impact Aircraft

Tags: Air

State of the Art - Background

In the view of reducing aircraft noise for people living around airports, several options are available, as outlined in ICAO's balanced approach:

- Noise reduction at the source;

- Low noise operational procedures;

- Land use management;

- Operational restrictions.

Since "operational restrictions" have a severe economic impact, the focus of the solutions should be to work in parallel on the other 3 options. OPENAIR focusses on the first approach: "Source noise reduction", which in practice means lower noise emissions from the aircraft's engines, landing gear and wing.

Several European research projects working on these subjects have already been performed: In 2001, the SILENCE(R) project gathered the preparation activities from FP3 and FP4, which had resulted in a large number of technologies achieving TRL 3-4. SILENCE(R) then took these efforts to a TRL6-7 level by performing ground and flight tests on engines and aircraft. Full scale TRENT and CFM56 engines as well as A320 and A340 aircraft took part in this validation exercise that ended in 2007. A technology evaluation exercise at the end of this project, showed that these "generation 1" technologies, when applied to a future fleet would improve the noise impact by 3 dB. Taking into account also improved operational procedures that were developed in parallel in other projects, a total improvement of 5 dB was achieved. This is considered as a good result given the 10 dB ACARE objectives for 2020.

Among the SILENCE(R) technologies, there were also a few future generation or "generation 2" technologies, like the "Active Stator", which were tested succesfully, but did not yet achieve the full technology readiness status. These, and other "generation 2" technologies are now further developed in OPENAIR.


By adopting a whole aircraft approach based on the latest developments in active/adaptive technologies, flow control techniques and advances in computational aero-acoustics applied to the major causes of noise at source, OPENAIR aims to deliver a 2,5 dB step change in noise reduction, beyond the SILENCE(R) achievements. The plan supports realistic exploitation of promising design concepts driven by noise reduction and should result in the development and validation of up to TRL 5 of '2nd Generation' technology solutions.

Description of Work

OPENAIR's multidisciplinary approach and composition is suited to the projected integrated, lightweight solutions. The process includes a down-selection at half life of the project. The selected technologies will be subjected to scaled rig tests, and the resulting data will support assessment of the noise reduction solutions on powerplant and airframe configurations across the current and future European range of products. The project exploitation plan is expected to include proposals for further demonstration in the Clean Sky JTI. The verification of the technologies' applicability will be assured by addressing identified integration and environmental tradeoffs (performance, weight, emissions).

Expected Results

OPENAIR will develop solutions that can play a significant role, along with the previous Generation 1 effort, enabling future products to meet the ACARE noise goals and improving current fleet noise levels through retrofitting. This capability is key to providing the flexibility needed to simultaneously accommodate market requirements in all segments, global traffic growth and environmental constraints, while addressing the global environmental research agenda of the EU.