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Fault Tolerant Aileron Actuation System for Regional Aircraft

Periodic Reporting for period 3 - TAIRA (Fault Tolerant Aileron Actuation System for Regional Aircraft)

Reporting period: 2020-04-01 to 2021-12-31

The aircraft primary flight surfaces are actuated mainly by Hydraulic Actuators (HA) when Electro-Hydrostatic Actuators (EHA) are used as a backup (e.g. Airbus A380 and Gulfstream G650). Electro-Mechanical actuators (EMA) are used mainly for actuating secondary flight surfaces (e.g. Boeing B787). To reduce the weight and power consumption of actuation systems, the more electric actuation is becoming demanded. The latest programs and activities (e.g. Smart Wing by SAGEM, More Electric Initiative or All Electrical Wing by CASA) are heading to a wing without hydraulic pipes supplying actuators that means using EMA/EHA instead of HA. The electric actuators are further step on the path from Fly-By-Wire to Power-By-Wire system where the central hydraulic supply and several hydraulic circuits are not needed at all.

The TAIRA is linked to the work plan of Regional Aircraft IADP within Clean Sky 2, specifically to the Work Package 2.4 Innovative Flight Control System. The project results will enable reliable electro-mechanical aileron actuation, the last step needed to dispose of the aircraft hydraulic system. This will significantly reduce the aircraft weight and fuel consumption, and in addition it will reduce energy reserves inherently needed in each power system leading to lower specific fuel consumption. Elimination of the hydraulic system has many advantages:
• Reduced maintenance costs
• No hydraulic oil (no need of replacement and disposal)
• Increases modularity of the aircraft, enabling wider component sourcing
• No risk of oil leakage, with positive environmental and airport safety implications

The overall project objective is to develop an aileron actuation subsystem for regional aircraft consisting of two EMAs, planned for active-active operation of single aileron, and two dedicated Electronic Actuator Control Units (EACU), and to demonstrate its maturity. The subsystem is being designed to achieve the following high-level objectives:
1. Compact & Lightweight EMA Design
2. Safe Actuation System
3. Easy & Cost-Effective Maintenance

3pcs of aileron actuation subsystem meeting the above-mentioned high-level objectives, and the Test Bench (TB) were delivered and installed at Topic Manager (TM) in 2021. Honeywell team will provide TM with a further technical support during demonstration activities on the TB and Iron Bird also in 2022 and 2023. The TAIRA project is considered as successfully accomplished.
The TAIRA was launched in April 2017. The project plan is divided into 6 logical development phases:
1. Requirements’ definition
2. Preliminary design definition
3. Critical design definition
4. Actuation units manufacturing
5. Actuation units testing and delivery to the TM
6. Customer support for integration and V&V on the Iron Bird simulator

In the requirements definition phase, the project team defined the most appropriate actuation subsystem architecture based on long term experience in the development and production of both, the Electro-Mechanical Actuator and the Fly-By-Wire Flight Control Systems (FCS). Detailed actuation subsystem architecture trade studies were performed focusing on many aspects of the future FCS to maximize the foreseen benefits of EMA based actuation.

The Preliminary Design (PD) phase started in October 2017. During this phase, Honeywell progressed with the actuation system design. The PD phase was accomplished in 07/2018.

Detailed design included development of 100s of mechanical and electronic components drawings and conducting multiple technical analyses. To de-risk potential future non-compliance with the requirements, an mock-up was developed and used for performance validation of the detailed design. Another effort was invested in development of the TB detailed design (HW, SW and Mechanical part). This phase was accomplished by the Critical Design Review in 08/2019.

Actuation Units (AUs) and TB manufacturing started in 09/2019 and all AUs and TB were assembled in 08/2020. Functional testing including the troubleshooting and de-bugging was made from 09/2020 to 02/2021. In parallel, the TAIRA team was working on preparation of the final verification testing that was accomplished by the Test Readiness Review (TRR) in 02/2021.

The final testing activities were made in 03-04/2021. The period of 05-06/2021 was dedicated to testing results’ review. The TB and two AUs and EACUs were delivered and installed in TM’s lab in Torino in 07/2021. In the rest of 2021, the TAIRA team provided TM with a customer support. This phase included support during TM‘s testing on the TB, troubleshooting and making additional tests.

The project results, 3pcs of EMA, 3pcs of EACU and TB, have been delivered to TM to be exploited for further demonstration activities. The results were disseminated on the AEC2020 conference in Bordeaux in 02/2020 and on the workshop organized by Brno University of Technology in 10/2021.
The TAIRA project brings an improved Actuation system performance with lower maintenance cost to the market. The following main impacts to the European aircraft manufacturers are expected:
• 150kg weight saving. This expected weight saving on aircraft level can be transferred into less fuel burn or additional passengers.
• 4% fuel saving. A hydraulic actuator is a continuous load on the engine whether hydraulic power is used for actuation or not. An EMA however can be configured using a “power on demand” strategy. Consequently, this reduces fuel consumption at engine level.
• 4% reduced aircraft emissions. Due to the obtained weight and energy savings, the TAIRA EMAs will help the aircraft to reduce fuel burn, and thus environmental pollution. This is a significant impact that helps the industry meet the ACARE SRIA and Flightpath 2050 goals.
• Reduced pollution and waste. The elimination of hydraulic fluids helps removing the environmental impact of wasted fluids (due to leakages during operation, or spills during maintenance works). The reduced need for spare parts (due to higher MTBF and Condition Based Maintenance) helps reducing overproduction and consequential waste material (waste material from production, and spare parts stock that never is used).
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