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Japanese-European De-Icing Aircraft Collaborative Exploration

Final Report Summary - JEDI ACE (Japanese-European De-Icing Aircraft Collaborative Exploration)

Executive Summary:
Ice accretion on aircraft structures is a threat to aviation safety, playing a key role in several severe accidents, which killed crews and passengers and destroyed aircrafts (e.g. ATR42 accident in Roselawn). Under non-icing conditions air flows smoothly over the airfoil and creates lift. Wing icing usually starting at the leading edge disturbs laminar airflow and causes overall turbulences in the concerned areas, increasing drag and decreasing lift drastically. Consequently aircraft icing degrades performance and controllability and increases significantly pilot workload and aircraft fuel consumption.
JEDI ACE aimed to provide an innovative concept of an integrated ice protection system: an integrated approach, consisting of combined passive anti-icing coating, active de-icing devices and ice sensors. The system is applicable to aircraft wings and supports an important technological milestone: the composite wing concept, which today includes also morphing properties.

The JEDI ACE consortium, consisting of European and Japanese beneficiaries, determined three technical objectives for an integrated ice protection system:
1. An active de-icing device based on electro-thermal and/or mechanical actuation, combined with supporting passive anti-icing coatings
2. An ice sensor system for real-time measurements of ice accretion on aircraft structures,
3. An integrated ice protection system with complementary components for excellent operation properties.

The work in JEDI ACE resulted in lab-scale prototypes for objectives 1 and 2 as well as a validated design concept for the future generation of integrated ice protection systems: the “JEDI ACE concept for an integrated ice protection system”.
The design contributes to:
- prevention of ice buildup on leading edges,
- improved in-flight ice assessment,
- improved aircraft safety
- reduced energy consumption during de-icing procedures,
- reduced de-icing procedures on ground,
- compliance with design constraints of composite wings,
- compliance with design constraints of wings with morphing properties,
- compliance with bleed-air free engines and all-electric aircrafts,
- compliance with other surface and coating requirements like resistance against erosion.

The JEDI ACE consortium developed lab-scale prototypes for combined de-icing devices with anti-icing coatings (objective 1) and ice sensors (objective 2). This work is based on a pre-selection of appropriate technology approaches that have been further developed to fulfill pre-defined requirements. Most promising technologies out of this work have been selected for an integrated design concept for a global ice protection system (objective 3). This system is designed as a modular system consisting of individual components that can be used separately as well as in combination, thus ensuring a maximum technological output achieved by JEDI ACE. This ambitious goal was achieved by combining the specific State-of-the-Art competencies through close multinational collaboration.

In order to achieve the targeted results of JEDI ACE the project was broken down into 9 research work pack-ages, 1 dissemination & exploitation work package and 1 management work package.
As shown in the interdependencies diagram (see figure “JEDI ACE concept for an integrated ice protection system”) the project was made of three phases:
Phase 1: Enabling technologies (WP1 to WP4),
Phase 2: Development of lab-scale prototypes (WP5 to WP7),
Phase 3: Demonstration and evaluation (WP8 and W9).
WP10 covered all dissemination and exploitation (D&E) activities and WP11 the management activities and the scientific evaluation for the complete project duration.

Project Context and Objectives:
Ice accretion on aircraft structures is a threat to aviation safety, playing a key role in several severe accidents, which killed crews and passengers and destroyed aircrafts (e.g. ATR42 accident in Roselawn). Under non-icing conditions air flows smoothly over the airfoil and creates lift. Wing icing usually starting at the leading edge disturbs laminar airflow and causes overall turbulences in the concerned areas, increasing drag and decreasing lift drastically. Consequently aircraft icing degrades performance and controllability and increases significantly pilot workload and aircraft fuel consumption.
JEDI ACE aimed to provide an innovative concept of an integrated ice protection system: an integrated approach, consisting of combined passive anti-icing coating, active de-icing devices and ice sensors. The system is applicable to aircraft wings and supports an important technological milestone: the composite wing concept, which today includes also morphing properties.

JEDI ACE aimed successfully to provide an innovative concept of an integrated ice protection system: an integrated approach, consisting of combined passive anti-icing coating, active de-icing devices and ice sensors. The system provided will be applicable to aircraft wings and will support an important technological milestone: the composite wing concept, which today includes also morphing properties.
The JEDI ACE consortium, consisting of European and Japanese beneficiaries, determined three technical objectives for an integrated ice protection system:
1. An active de-icing device based on electro-thermal and/or mechanical actuation, combined with supporting passive anti-icing coatings
2. An ice sensor system for real-time measurements of ice accretion on aircraft structures,
3. An integrated ice protection system with complementary components for excellent operation properties.

The work in JEDI ACE resulted in lab-scale prototypes for objectives 1 and 2 as well as a validated design concept for the future generation of integrated ice protection systems. The design contributes to:
- prevention of ice buildup on leading edges,
- improved in-flight ice assessment,
- improved aircraft safety
- reduced energy consumption during de-icing procedures,
- reduced de-icing procedures on ground,
- compliance with design constraints of composite wings,
- compliance with design constraints of wings with morphing properties,
- compliance with bleed-air free engines and all-electric aircrafts,
- compliance with other surface and coating requirements like resistance against erosion.

The JEDI ACE consortium developed lab-scale prototypes for combined de-icing devices with anti-icing coatings (objective 1) and ice sensors (objective 2). This work is based on a pre-selection of appropriate technology approaches that have been further developed to fulfill pre-defined requirements. Most promising technologies out of this work have been selected for an integrated design concept for a global ice protection system (objective 3). This system is designed as a modular system consisting of individual components that can be used separately as well as in combination, thus ensuring a maximum technological output achieved by JEDI ACE.
All determined objectives within JEDI ACE have been achieved by using newest scientific knowledge, combined with ground ice tests simulating flight conditions to validate the performance of the com-ponents and deliver the design concept of an integrated ice protection system. This ambitious goal has been achieved by combining the specific state-of-the-art competencies through close multination-al collaboration.

The multinational consortium in JEDI ACE consisted of a well-balanced selection of European and Japanese beneficiaries, including aircraft manufacturer, research institutes, universities and an administrative institution. The participating beneficiaries have gained a lot of experience in previous as well as running research projects. For example, beneficiaries are involved in following EU-funded projects, dealing with issues also addressed in JEDI ACE:
- Clean Sky as central EU project related to aircraft industries is facilitating manifold research and development activities. Fraunhofer and Dassault are participating to this project. This includes activities for Smart Fixed Wing aircraft, taking into account surface technologies for different functionalities, including anti-icing surfaces. The pronounced duration is 2008-2014.
- EXTreme ICing Environment (EXTICE) deals with the effects of Super Large Droplets (SLD) and is related to aircraft structures. Dassault is participating and expected project end is mid of 2012.
- High Altitude Ice Cristals (HAIC) is also related to aircraft icing with the emphasis on engine inlets. Dassault is involved in the project.
- ON Wing Ice DetectioN and MonitorinG System (ON-WINGS) is related to ice detection and the project end is pronounced with autumn 2012. The JEDI ACE consortium will invite bene-ficiaries of this project to technical workshops in order to be able to take these experiences into account.
- Smart Intelligent Aircraft Structures (SARISTU) investigates the application of morphing structures for aircrafts. Fraunhofer is involved in this project. This will help to ensure the compatibility of technical solutions, derived in both projects.
- CLEANSPACE-Small debris removal by laser illumination and complementary technologies is a project URV is involved with the focus on laser technologies that is also used in JEDI ACE for ice detection approaches.

The participation in diverse research projects reflects the great experience of the JEDI ACE partners. Japanese consortium beneficiaries also delivered a broad range of experiences in the field of aviation industry, optical measurements, icing forecast, anti-icing coatings as well as ice testing. The close collaboration was essential to achieve the aimed goals & objectives and it will help to further mature the results of JEDI ACE in future projects. JEDI ACE also affected the following aspects:
- Sharing know-how and experience from Japan and Europe,
- Extent global value-added chain,
- Improve access to the Japanese / European market, respectively.

Project Results:
For many decades, the leading technology for de-icing procedures on wing leading edges has been the use of bleed air. However, this technology faces several drawbacks as for instance high energy consumption which decreases the engine efficiency. Furthermore, during start phase the use of bleed air is restricted as all energy is used for turbines. This requires a proper de-icing procedure on ground, using chemical freezing point depressors (e.g. glycol mixtures) that also prevent new ice accretion during start phase.

The JEDI ACE concept comprises the development of a new generation of integrated ice protection systems which is addressed mainly to in-flight icing. Furthermore, it supports ground de-icing as active de-icing devices may be used on ground, too. In the following the three objectives in JEDI ACE are described. Once they are achieved a significant advantage for usage on commercial aircraft will be created with considerable benefits in fuel consumption as well as in cost- and time-savings. The system is applicable to composite wings. This technology will further enhance aircraft safety, making aircraft less susceptible to unpredictable weather conditions and human error.

Objective 1:
Active de-icing device based on electro-thermal and/or mechanical actuation, combined with supporting anti-icing coatings.
The use of electro-thermal or electromagnetic de-icers in aircraft wing leading edges has already been actively promoted worldwide, and some systems are being put in practical use. The JEDI ACE consortium identified the following aspects to be considered:
- Electro-thermal de-icing devices that can be heated in required areas only. These areas will be identified by the real-time icing sensor system. This integrated system will require less energy compared to de-icing devices that heat complete areas without any ice sensor system.
- Electromagnetic mechanical systems. A feasibility study was performed on electro-magnetic mechanical systems, which can also be used for de-icing purposes. For these systems, supporting anti-icing coatings were of special interest as they can reduce ice adhesion properties and improve effectiveness of the combined system. (For coating approaches see further below.) Furthermore, the effects on composite materials regarding vibrating impacts need to be taken into account.
- Shape Memory Materials (SMM, e.g. Ni-Ti alloys). A further approach that was investigated in the feasibility study is the use of shape memory materials that are able to change their shape in response to external stimuli (such as heat or electricity). This material combined with elastomeric anti-icing coatings could be used to mechanically de-ice leading edges on demand.
- Anti-icing coatings. The development of anti-icing coatings that support the active de-icing device was one of the major tasks within JEDI ACE. Such coatings can on the one hand reduce ice adhesion significantly; on the other hand minimize wetting behavior of surfaces to prevent / reduce ice accretion. The application of such coatings on the surface of active de-icing devices will significantly ease the ice removal and will delay de-icing cycles due to ice accretion prevention. The development of such coatings will be accompanied by further re-quirements, including erosion resistance, UV-resistance and appropriate durability. The beneficiaries worked on hydrophobic coatings and hierarchical structured coatings using functional pigments and a UV-curing structured process.

All defined aspects have been developed and investigated in terms of pre-defined requirements, effectiveness, and applicability in the integrated JEDI ACE ice protection system. At the first stage, the most promising technologies have been selected in WP3 for further developments in WP6 to combine active de-icing devices with passive anti-icing coatings. The optimum combination of both components have been selected on the basis of ice performance tests in WP8. This will lead to highly efficient de-icing processes by significant reduced energy consumption and will contribute to a fail-safe anti-icing system. The resulting prototypes will be delivered to WP9 to be used for the development of an integrated ice protection system and are part of this modular system.

Objective 2:
An ice sensor system for real-time measurements of ice on aircraft structures
The proposed ice detection system is an improvement in terms of safety since the occurrence of ice accretion may be identified or confirmed in an early stage and appropriate actions can be initiated in a timely manner. New developments in icing sensoring suggest that an optical sensor is a good solution for improving icing detection. In the JEDI ACE project two approaches have been evaluated:
1. Tele-sensor: The ice sensor detects ice on the profile of the critical surfaces from a viewing position located in the fuselage of the aircraft. This reports at least three distinct advantages:
• Measuring the ice directly to the points where it is critical (edges and engine inlets).
• No need to drill the wing or install wiring in it. The wing is intact. And this aspect is a fundamental difference from other proposed ice detection systems that have not been yet implemented commercially.
• The wing de-icing systems can function properly because the ice detector does not interfere.
2. Flush mounted sensor: The ice sensor is a sub-millimeter device inserted in the leading edge where the wiring for input current and signal is integrated with the active de-icing de-vice. This delivers the following advantages:
• Measuring the ice directly in the points where it is critical (edges and engine inlets).
• System integrated with the anti-icing system.
• Not interfering with the anti-icing system because of its reduced size.

The implementation of these technologies could lead to the following advantages:
1. The consumption of the aircraft is reduced since only anti-icing systems are activated when necessary, and not when there is probability of ice as it is done at present by airliners. Fuel economy depends on many factors, but the reduction in fuel consumption may be estimated between 1% and 8%.
2. Pollution emissions of CO2 and other combustion gases are also reduced as a result of reduced consumption.
3. Flight safety is increased because it measures the presence of ice on critical parts of the structure like the leading edges and the jet engines inlets.
4. The monitoring of critical surfaces can be displayed on the cockpit main screen for the crew to have fast and reliable information about the state of these surfaces and to act in the best way in every case.
5. Such system has the potentiality of activating de-icing systems automatically, reducing the crew workload, especially in difficult situations like turbulent approaches inside clouds, with precipitation, near thunderstorms, etc.
Requirements for this objective have been defined in WP1. On that basis concepts of both ice sensor types were evaluated in WP4 and delivered to WP7. Further developments of lab-scale prototypes were carried out, taking into account ice test results (WP8) and a construction plan was delivered to WP9 (month 27).

Objective 3:
An integrated ice protection system with complementary components for improved operation properties.
The integration of the former two objectives to a completely new and innovative ice protection system on a modular basis which is applicable to composite wing structures was the third objective defined in JEDI ACE. The development of the previous described combined de-icing device and the smart ice sensor will result in a complementary modular system that shall include the following properties:
- Real-time ice detection on relevant surfaces,
- Integrated design concept giving information directly to the cockpit and – if necessary - induce de-icing procedure,
- De-icing of relevant surfaces with the minimum of required energy,
- Controlling of de-icing process and de-energizing of de-icing device directly after ice removal,
- Prevention / reduction of icing due to applied anti-icing coating.

The realization of such integrated ice protection system that can decrease the amount of icing and facilitate de-icing contributed to the improvement of air safety and efficiency of ground de-icing. The tasks for the integration have been defined in WP9, that basis on the experience of all former RTD related work packages. This objective included an estimation concerning improved energy efficiency compared to today's de-icing procedures.
All developments within JEDI ACE take into account complementary issues, resulting in an integrated ice protection system contributing to:
- Reduced energy consumption,
- Improved flight air safety.

Potential Impact:
The overall aim of JEDI ACE was the development of a concept for an integrated ice protection system on the basis of a modular system that is applicable to composite aircraft structures and reduces fuel consumption and improves safety of aircraft operations. The major innovations achieved within JEDI ACE will have a strong impact on future design concepts for aircraft anti-icing systems. These are:
- De-icing devices combined with anti-icing coatings
- Durable anti-icing coatings
- Concepts for shape memory materials (SMM) as de-icing devices
- Base technology for Primary Inflight Ice Detection System (PIIDS) on optical basis
- European / Japanese ice sensor technology that competes with the dominant American company Goodrich
- Modular concept that integrates all components in a global ice protection system

These innovations will result in a series of technical, environmental and socio-economic impacts as outlined below:
The major technical impact results from the modular ice protection system, which consists of individual parts and act in an integrated global system. This will improve aircraft safety (aims to reduce accident rate by 80%). The novel robust icing sensor system contributes to this impact significantly as optical sensor, detecting ice accretion on the relevant surfaces of an aircraft (like leading edges and engine inlets), is a substantial progress in this technological sector. Furthermore, this technology contributes to energy savings as de-icing procedures can be monitored in real time and the de-icing system can be switched off without the need of extended heating time for safety issues. The improved de-icing device developed in this project also contributes to energy savings and the use of durable anti-icing coatings will ease the removal of ice on surfaces.
The work in the multinational consortium assures the technological leadership of the participating partner in the EU as well as in Japan. The gained knowledge on in-flight and ground ice formation contributes to this impact.

The socio-economic impacts that can be expected are the increased aircraft safety and the replacement of energy intensive de-icing procedures. The use of the proposed integrated ice protection system will mitigate human errors and hence reduce accident rates. The major improvements will lead to an increased competitiveness of European and Japanese aeronautic industry and consequently to increased employment. This is underlined by the following data: In the years 2000/2001 the total European aerospace production industry employed approximately 435.000 persons, Europe’s airline industry employed approximately 370.000 persons and the complete European tourism industry employed 9.000.000 people (figures from the European Association of Aerospace Industries). Japanese aerospace production industry employs 20.000-30.000 persons. Although the defense expenditure of Japan is reduced in the past several years, the total sales of aerospace industry are increasing. However, countries of Asia, such as South Korea and China, have also heightened technical capabilities. Therefore, it is necessary to develop advanced technologies in Japan.
As the industries mentioned have been under severe pressure some years ago, the conservation and future expansion of employment will necessitate a high competitiveness. The project results will play a key role in addressing this issue, both by generating added product value for aircraft manufacturers and improved safety of aircraft operations.

Another huge potential field of application is wind energy. Wind energy production in cold areas, which increases currently due to the exploitation of natural power sources, suffers from the lack of a suitable anti-icing systems and reliable icing sensors. Icing leads here to a loss of aerodynamic efficiency by 20-30% and in inhabited areas wind energy plants often have to be switched off at icing conditions. The existing anti-icing system that needs additional energy can not be realized economically. All three objectives of this project (Combined de-icing devices with passive anti-icing coatings, ice sensors and finally integrated JEDI ACE ice protection system) would help to overcome the icing problem in this industry. The requirements for rotorblades of wind energy plants are quite comparable to aircraft wings in terms of substrates (fiber reinforced plastics), weather resistance and erosion. Furthermore, passive anti-icing coatings will also be applicable to power lines, buildings, automobiles, railways, etc. This extends the field of application significantly and improves competitiveness for ice protection technologies.
Aircraft icing is global issue that is discussed in SAE International Conference etc. Especially EU aims to develop environmental friendly technologies. This comprises the replacement of energy intensive and chemical-based de-icing procedures and is the overall aim within JEDI ACE. This will contribute to a “greener aircraft” and will also affect other technological sectors. The technical impacts are summarised in the following:

Reduction of accident rate by 80 %
JEDI ACE aims for the development of improved sensor systems and in-flight monitoring of icing exactly on the areas where icing occurs and leads to dangerous situations (wing-leading edge, horizontal tailplane etc.) in real-time. Errors coming from delayed de-tection of icing will be eliminated due to the development of the real-time sensing system, applied directly to the areas of the aircraft where icing occurs (in contrast to current systems). The combination of the new sensing system with the currently used one will introduce a higher level of redundancy and by this means reduce the probability of accidents.
The implementation of the integrated system will additionally lower the probability of human errors (see below).
The technologies developed in this project will reduce the number of accidents due to icing significantly.

Achievement of a substantial improvement in the elimination of and recovery from human error
One objective of the JEDI ACE project was the development of an integrated system, consisting of a combination of real-time sensing and active de-icing. Human error (for instance the pilot switches on the de-icing system too late) will be eliminated.

Mitigation of the conse-quences of survivable accidents
No direct effect because proposed system is designed to prevent accidents; however, indirect effects may appear in case of disturbances under severe weather conditions as the new JEDI ACE ice protection system contributes to improved manoeuvrability properties under harsh weather conditions.

List of Websites:
www.jediace.net