Engineering a route to greener skies

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Today’s aviation industry faces increasingly stringent global emissions regulations and a public perception of air travel as an unsustainable mode of transport. Being under increasing pressure to minimise its environmental impact, aerospace electronics engineers are rethinking design principles, component selection strategies and system architectures to contribute to reduced emissions, lighter aircraft and more efficient power management.

In response, IATA, the industry’s trade association and its members have committed to net-zero CO2 emissions by 2050. Achieving this ambitious target is driving an industry-wide transformation, with initiatives encompassing everything from sustainable aviation technologies and alternative fuels to energy-efficient aircraft and enhanced passenger and ground operations.

The transition to More Electric Aircraft (MEA) is key to this ‘Fly Net Zero’ initiative. Traditional hydraulic and pneumatic systems are being increasingly replaced with electric alternatives, resulting in enhanced efficiency, reduced weight and lower operating costs. 

The All-Electric Aircraft (AEA) is still several years away for larger commercial flights but significant progress is being made in developing hybrid-electric and fully electric options for smaller aircraft operating on regional routes. For the aviation industry, this is an exciting period of opportunity and change.

The important role of design engineers
As the efficiency and safety of modern aviation systems rely increasingly on electronic systems, the opportunities – and responsibilities – for design engineers are expanding rapidly. The drive for efficiency and weight savings demands a bold approach to avionics, requiring systems architects to make crucial platform-level decisions. Is it feasible to eliminate hydraulics and pneumatics from the aircraft? What about the power distribution strategy – is the supply chain mature enough to support a wholesale migration to higher voltages?

Aviation system designers must continually focus on efficiency optimisation, maximising power usage and minimising emissions. Energy management is critical, demanding a total lifecycle approach when developing intelligent power systems.  

Additionally, with safety paramount in aviation, designers must be reliability champions, insisting on step-change improvements in an electrical system’s performance over current capabilities. And, perhaps most importantly, the role of the integration specialist is essential to the seamless operation of multiple complex aircraft systems. 

Design principles and strategies for sustainability
Within this challenging context, sustainable aviation design must balance visionary ambition with proven engineering design principles and methodologies, with SWAP-C criteria (size, weight, power and cost optimisation) at their core. Modular architectures enable technology to be reused and scaled efficiently across different platforms, significantly reducing both cost and development time. Advanced intelligent energy management systems are key enablers of efficiency, ensuring the effective harvesting and redistribution of power.

Rigorous systems integration methodologies combine various subsystems into a cohesive whole, improving interoperability, while enhancing performance, reducing costs, and improving overall functionality and safety. Future-proofing designs ensures that platforms retain flexibility as regulations and technologies evolve, and lifecycle thinking considers the impact of design decisions on manufacturing and operation through to end-of-life management, maximising sustainability at every stage of the aircraft’s journey.

The growing investment in hybrid-electric propulsion vividly illustrates many of these principles. Modular architectures, for example, allow engineers to trial hybrid powertrains on smaller regional aircraft before scaling up to larger airliners. These hybrid systems offer an immediate opportunity to cut emissions on regional routes while demonstrating how scalability and practicality can coexist in real-world applications.

Components and enablers of sustainable design
Fundamentally, sustainable aviation systems rely on a core set of electrical technologies for power generation, distribution and management, as well as for powering avionics and other critical systems.

Electrical power conversion systems are widely recognised as a cornerstone of the industry’s sustainable future. Fundamental enablers of the MEA concept, these systems efficiently distribute and manage electrical power, converting between different forms (AC and DC) and voltage levels to meet the diverse needs of the various onboard systems. High-efficiency converters using silicon carbide (SiC) and gallium nitride (GaN) are enabling smaller, lighter and more efficient systems that drastically reduce power losses.

Bi-directional power systems in modern aircraft unlock new approaches to energy recovery. Unlike traditional unidirectional power supplies, which only deliver power, these systems can both supply power to a load and absorb power from it, allowing the transfer of electrical energy in both directions. Bidirectional power systems are crucial for various applications, including energy storage. Excess power from motors or subsystems during low-demand phases can be fed back into batteries or other loads, for example, improving operational efficiency and directly supporting the wider trend towards electrified propulsion.

Smart sensing networks monitor various operational aspects of an aircraft in real-time, enabling systems to be dynamically optimised, improving efficiency, extending component life, and reducing unplanned downtime. Smart sensors are typically used for structural health monitoring (SHM), environmental monitoring, and engine health monitoring. Sensor technologies are emerging that monitor pilot alertness and passenger biometrics, enhancing safety and potentially improving the overall travel experience. Sensor types include fibre optic, piezoelectric, guided wave, and current sensors, with Micro-Electromechanical Systems (MEMS) sensors increasingly used due to their miniaturisation levels, reduced cost, and enhanced performance. Both wireless and wired sensor networks are deployed, depending on the specific application and location within the aircraft. 

Battery integration is key for a more sustainable and efficient aviation industry. Batteries play a crucial role in the MEA, beyond just engine starting and backup. At the heart of an integrated energy management system, they provide power for various systems and are central to peak load balancing and energy recovery, and support propulsion in hybrid or fully electric designs. Lithium-ion batteries currently dominate due to their relatively high energy density and established manufacturing infrastructure, but solid-state batteries are seen as a promising next-generation technology, offering even higher energy density and potentially enhanced safety. 

High Voltage (HV) Distribution is critical, too. As the trend towards MEA drives an increase in the number of electrical components and systems, the need for interconnectivity grows. With electrical wiring harnesses currently representing anything between 1% to 3% of the aircraft’s empty weight, manufacturers are considering replacing or complementing traditional AC systems with HVDC systems. 

Higher voltage levels require less current for the same power transmission, leading to smaller and lighter wiring harnesses and hence significant weight savings for next-generation aircraft. Today’s platforms typically use 270 volts or 540 volts, but higher voltages such as 800 volts or even 1200 volts are being explored. Ultimately, distribution levels of several kilovolts will be required to support the power requirements of future platforms such as electric propulsion.

These technologies will be critical to the development of more sustainable aircraft – and aviation companies are increasingly looking to partner with suppliers that can offer a systems-led approach. 

Green skies ahead
Global pressures to increase sustainability are driving a transformation of the aircraft industry and advanced electronics systems are playing a key role in this transformation. The trend towards More Electric Aircraft is seeing an increasing electrification of key aviation systems, enabled by advances in power conversion, power distribution, battery management and sensing technologies.  

The All-Electric Aircraft may be some years away but the roadmap towards it is based on modularity and scalability. Market success will be based on the ability to successfully test, prove and scale architectures through successively larger aircraft structures.