Icing in the context of sustainable aviation

The need to perform research in the field of icing, to ensuring safety and efficiency of proposed new solutions (TRL 3-5), is justified by the increasing incidence of weather hazards caused by climate change, the new generation of low carbon dioxide (CO2) aircraft with associated disruptive configurations, and the stringency of new policies and certification rules.

In the mid-term, project results are expected to contribute to the following outcomes:

• Generating scientific expertise to develop means of compliance for the certification of icing systems;
• Generating scientific knowledge to be able to develop new prototypes of ice detection and protection.

The field of aircraft icing is of particular importance because it relates to the safety of flight facing adverse weather conditions, which became increasingly extreme during the last decade.

The aviation industry is working to develop clean and sustainable aviation. There is the need to innovate while maintaining safety.

To enable design, validation and future certification of new technologies emerging from cleaner aviation, R&I should be initiated on the following three principal areas ( proposals should consider addressing all, or significant areas of all, three areas):

1. R&I to prepare for the development of means of compliance for certification of future sustainable aviation concepts including:

• Development of reliable numerical tools to be used to validate the designs against the icing environment of Appendix C, O, P and snow, including ground anti-icing fluids;
• Development of Supercooled Large Drop (SLD) Testing Capabilities such as icing wind tunnel test or ice tankers. Generation of flight-testing open datasets for validation of modelling and tunnel testing;
• Development of European Ice Crystal test Capability (for engine/air data probe);
• Development of Falling / Blowing Snow Testing Capability.

2. R&I on Icing environment to assess the impact of the climate change effects on the certification icing environments^[1].

3. R&I related to new technologies for Ice detection and protection, including:

• Ice crystal and SLDs Ice Detection systems to optimise Ice crystals protection or support the detect and exit the SLD appendix O or a portion of the appendix O conditions;
• High Efficiency/Low Energy protection: cleaner aviation with more electric airplanes will drive the need for new ice protection technology: more effective and with less energy, active, passive and hybrid technologies (e.g., low ice-adhesion durable coatings and including new air mobility products (e.g., low speed propeller icing concerns);
• Dissimilar means for Air data (angle of attack (AOA)/Speed) measurement and insensitive to icing threat. Air speed and aircraft attitude measurements are crucial for aircraft control. Air data/navigation probes are externally mounted and exposed to adverse conditions. Dissimilar means to determine the aircraft speed and altitude would provide benefits and make the air data system even more robust and fault tolerant to environmental conditions (icing or hail);
• Enhanced aircraft performance and in particular ice protection health monitoring by improving the ice protection system monitoring coverage based on smart systems capable to monitor a large number of aircraft parameters.

This research and innovation topic is linked to several ongoing rulemaking actions of the European Union Aviation Safety Agency:

1. RES.0010 Ice Crystal Detection
2. RES.0017 Icing hazard linked to super cooled large droplets (SLD)
3. RES.0014 Air-data enhanced fault detection and diagnosis
4. RMT.0196 Update of the flight simulation training device requirements
5. RMT.0118 Analysis of on-ground wing contamination effect on take-off performance degradation

A close cooperation with the European Union Aviation Safety Agency (EASA) and with notational aviation authorities during the implementation of this project should be envisioned.

[1] Note: the project will assess the use of specific models for the prediction of icing conditions (e.g., addressing cloud micro-physics for the formation ice crystals, super cooled water droplets), which can be coupled to climate models (e.g., General Circulation Models).