Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - TAIRA (Fault Tolerant Aileron Actuation System for Regional Aircraft)

Teaser

The primary flight surfaces of aircraft are currently 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...

Summary

The primary flight surfaces of aircraft are currently 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 (FBW) to Power-By-Wire (PBW) system where the central hydraulic supply and several hydraulic circuits are not needed at all.

This project is linked to the work plan of Regional Aircraft IADP within Clean Sky 2, specifically to the topics under 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 therefore specific fuel consumption), and in addition it will reduce energy reserves inherently needed in each power system (again 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 Electro-Mechanical Actuators, 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

Work performed

The TAIRA project 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 (EMA) and the Fly-By-Wire (FBW) 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 subsystem architecture trade studies dealt with the challenges, whether genuine to the EMA, such as safety risks associated with mechanical jam, or specific to regional aircraft application, especially the space restrictions for integration into wing structure. In a nutshell, the following progress was made in the requirements definition phase:
• System & component requirements were defined and agreed with the TM
• External Interface Control Document was developed and agreed with the TM
• System architecture was done
• System-level technology trade studies were done
• Preliminary safety system analysis was done
• Preliminary health monitoring studies were done
• Mechanical & electronic HW designs for the 1st Electronic Actuation Control Unit (EACU) development unit were done
• Top level Motor Control (MC) architecture was finalized
• Critical MC electronic components were selected
• Initial mechanical concept for MC was defined
• EMA mechanical design concept was defined
• Main EMA components and sensors were identified
• EMA & MC reliability budgets were allocated
• Preliminary EACU & MC control laws were defined

The preliminary design phase started in October 2017. During this phase, Honeywell significantly progressed with the actuation system design. The preliminary design phase was successfully accomplished after several review meetings with the Topic Manager (TM) in July 2018.

The project is in the critical design definition phase now.

Final results

The core ambition of the TAIRA project is to significantly improve the state-of-the-art of certifiable EMA subsystem for primary flight surface actuation system. This item is aligned with current global trends of aircraft electrification (More Electric Aircraft). On the project end, the EMA technology will be integrated and validated on the regional aircraft iron bird simulator. It will be a significant milestone on the path to deployment of Power-By-Wire system on regional aircraft.

The TAIRA project brings to the market improved Actuation system performance with lower maintenance cost. 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 EM actuator 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).