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SENSors and certifiable hybrid architectures FOR safer aviation in ICing Environment

Periodic Reporting for period 1 - SENS4ICE (SENSors and certifiable hybrid architectures FOR safer aviation in ICing Environment)

Reporting period: 2019-01-01 to 2020-06-30

Modern airplanes are well equipped to cope with the most common icing conditions, which are defined Appendix C of FAR Part 25 / CS-25. However, some conditions containing Supercooled Large Droplets (SLD) have been the cause of severe accidents over the last three decades. It has become clear that improving safety is of high importance for these icing conditions as ice can form on unprotected areas of the lifting surfaces. Consequently, authorities addressed these safety concerns by issuing new certification rules under Appendix O of FAR Part 25 / CS-25 to ensure that future airplanes remain controllable in these conditions and can exit safely upon detection. Hence, the key to increasing overall aviation icing safety is the early and reliable detection of icing conditions to allow the necessary actions to be taken by the flight crew. The EU-funded project SENS4ICE (SENSors and certifiable hybrid architectures for safer aviation in ICing Environment) directly addresses this need for reliable detection and discrimination of icing conditions.
Although much progress has been made on icing detection, there are considerable gaps which still exist, specifically regarding the newly introduced icing conditions of Appendix O. This is the focus of the novel approach of the SENS4ICE project which seeks to intelligently cope with the complex problem of ice detection through the hybridisation of different detection techniques. In the proposed hybrid system, the direct sensing of atmospheric conditions and/or ice accretion on the airframe is combined with an indirect detection of ice accretion on the airframe by monitoring the change of aircraft’s characteristics. SENS4ICE will address the development, test, validation, and maturation of the different detection principles, the hybridisation - in close cooperation with regulators to develop acceptable means of compliance - and the final airborne demonstration of technology capabilities in relevant natural icing conditions.
The developers of the direct ice detection sensors have defined the operating principles of their sensors and produced their plans for development within SENS4ICE. The work included the development of software, hardware, numerical analysis and testing of prototypes in the lab. In parallel, they have prepared the Interface Control Documents to provide detailed information on the physical and functional interfaces required for the installation of the sensors in the hybrid system, icing wind tunnels and aircraft. Such Interface Control Documents are formulated in close cooperation with the operators of the icing wind tunnels and flight test platforms to ensure that each partner understands the requirements, constraints and timeline for pairing the sensors with the research facilities and flying testbeds to be used in SENS4ICE. The test campaign in the icing wind tunnels is planned in winter 2020/2021to evaluate direct sensors measurements against reference probes based on ability to measure, detect, discriminate Appendix C and Appendix O. The results of the icing wind tunnel tests will be used in the first months of 2021 to evaluate and select the sensors suited for the project flight test campaigns and installation within the Hybrid Ice Detection System.
The various detection instruments have a wide range of maturity levels, from basic technology research to nearly flight ready systems. The instruments also use a wide range of detection principles to provide the hybrid system with a robust set of inputs from which the icing hazard threat can be determined.
In parallel, the project partners have progressed with the development of the indirect ice detection methodology consisting of the algorithm for detection of ice accretion including Appendix C and Appendix O conditions. Based on the principle of early detection of even light ice accretion on airframe, the methodology uses the fundamental knowledge about changed aircraft characteristics under icing conditions. Together with the direct ice detection sensors, the indirect ice detection is an important part of the hybrid ice detection system approach developed in SENS4ICE.
The consortium has also carried out fruitful discussions with the members of the SENS4ICE Advisory Board, especially during the last physical meeting that took place in February 2020 in Brussels and the virtual Review Meeting that took place in June 2020. The expertise and valuable insights especially of the certification agencies have supported the SENS4ICE partners in preparing an important deliverable on the guidelines for certification of the Hybrid Ice Detection System. This document describes the specific practices that are foreseen to demonstrate compliance with the applicable requirements for the Hybrid Ice Detection System. It also proposes a preliminary sketch towards the certification of the system.
The consortium unites European and international aircraft manufacturers, equipment suppliers, research/academia and consultancy SMEs with a large variety of technologies that have emerged in recent years. The most promising and mature of these technologies will be selected for flight testing, while several other less mature but promising technologies will be advanced in a laboratory environment. Since icing is a global hazard, SENS4ICE will address this challenge with a global consortium including participants from Brazil, USA, and Russia. By aligning the EU-funded activity with nationally and internally funded programmes of those countries, a harmonised global perspective on Acceptable Means of Compliance can be achieved, and technological progress can be further advanced by ensuring the coordination of research efforts and avoiding overlap.
The expected impact of the project is to contribute to the smart, green and integrated transport while addressing the challenges of the transport competitiveness, performance and sustainability. SENS4ICE will tackle these challenges by contributing to increased passenger safety, decreased cost by improving certification rules, and increasing aviation efficiency by avoidance of icing hazards, reducing unnecessary diversions due to false identification of icing hazards and lowering inspection and MRO operations.