Product
STERNA Hybrid Pack for aircraft
Promise
You're looking to hybridize your aircraft, you’re at the right place
Learn more
A resized and optimized engine for cruise flight
An electric boost at takeoff to provide the additional power needed
Automatic management of power split between the combustion engine and battery
(Our offer)
STERNA Hybrid Pack for aircraft
STERNA Hybrid Pack for aircraft is a modular, scalable system that combines two energy sources to progressively reduce aircraft emissions and achieve in-flight Net Zero.
(our Services)
Hybrid propulsion support from pack supply to system integration
Supply of Hybrid Pack to power your hybrid-electric development
Integration of complete hybrid propulsion system into your aircraft
Want to know how this applies to your aircraft?
(our Expertise)
Hybrid electric pioneers since the start, in 2018.
Built on true aircraft maker heritage
Hybrid Architecture Expertise
Optimized weight, seamless fit
(Applications)
Hybridization Gains
Hybrid-electric propulsion system to power your CTOL / fixed-wing or VTOL aircraft and improve your air operations' efficiency
Economics
Up to 50% less fuel burn, 30% lower operating costs, longer battery life, and faster turnaround for higher revenue.
Weight reduction
Thanks to best-in-class battery integration ratio (~80%).
Easy to Integrate
No BMS changes needed, comes with HEMS + HCU, and fits both linefit and retrofit.
Safe & Certifiable
Built to prevent thermal runaway, ensure safe component integration, and handle dissimilarities and LOPC.
Sustainable
Up to -30% CO2 emissions vs. thermal aircraft.
(Our technology)
Hybrid electric propulsion
system
A modular and scalable combination of two sources of energy (fuel + battery).
A hybrid-electric aircraft uses a mix of two energy sources: electric batteries, used during take-off and climb, to benefit from the instantaneous release of optimized, high-power engines that can run on Jet-A1, and sustainable aviation fuel or hydrogen tomorrow, for low-energy phases of flight, such as cruise.
Conventional aircraft
Aircraft equiped with Sterna
A conventional aircraft engine is usually sized for take-off and climb thrust requirements. This leads to an oversized engine for cruise flight, where most of the fuel is burned. Thanks to Sterna, we can decouple these 2 phases and optimize them to reduce overall fuel consumption over the entire flight.
During take-off and climb, the battery is used to provide high power for short periods. Thus, the powertrain does not need to provide the power during this phase, and take-off and climb rating can be removed and/or the powertrain downsized.
During cruising, the powertrain is used at maximum efficiency, as it is now specifically sized to achieve this level of performance.
Where innovation
takes flight
What does Sterna look like in an airplane?
Sterna is a set of technologies and components for aircraft and rotorcraft OEMs to make them more sustainable, whether for new developments or retrofitting existing aircraft with an STC*. Sterna can take several shapes depending on your aircraft and the program objectives, from turboprops to regional planes.
Hybrid Operating System
Energy management system - handles the energy split in the system
Hybrid Core
Electrical power box - connects all components together safely & distributes the energy in the system
We’re taking aviation
to new heights.
Embedded intelligence
From energy management to flight controls, including a complete set of data from engines, batteries, etc., the hybrid propulsion system simplifies maintenance operations and improves aircraft availability and customer service.
Range & endurance
The combination of different energy sources and top-grade energy management algorithms ensure optimal performance in flight (cruise time and speed) and on the ground. Our technology adapts to existing infrastructures and limits turn-around times.
Energy transition
Our modular architecture can be adapted to new generation aircraft with a wide array of energy sources, from kerosene and biofuels to synthetic fuels and hydrogen fuel cells.
Safe & efficient
Our hybrid propulsion system is engineered to match the requirements of future distributed propulsion systems, and embeds the required algorithms to control the multiplied number of propellers to ensure safe, efficient flight.
Fly clean
Our hybrid propulsion system significantly reduces carbon and noise emissions, for cleaner skies today and tomorrow. Sterna is the key technology and cornerstone of cleaner aviation.
Scalable
The complete hybrid propulsion system architecture can be scaled up to meet the future requirements of regional aviation, from 6-10 PAX up to 70 with current technologies, propelling aviation into a new sustainable era.
(our clients)
They chose our products
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Company
Jean-Baptiste Djebbari Joins Ascendance’s Strategic Committee
Jean-Baptiste Djebbari, former Minister of Transport, is joining our strategic committee
Technical progress
On the route to permit to fly
Ascendance was welcoming EASA for the 3rd time this year
Company
Ascendance has been ranked in the Top 100 of TIME's World’s Top GreenTech Companies of 2025!
Proud to be recognized among the world's top greentech companies! 🌍🌱
You have some questions?
We have answers
STERNA Hybrid Pack is the combination of 3 core components: a novel battery pack co-developed with our partner Exoes and natively designed for hybridization in aviation, a Hybrid Energy Management System (HEMS) who is the “brain” of the system and automatically manage the energy, and a Hybrid Core Unit (HCU) who connects together the engine and battery in a safe & certifiable manner.
Maximum performance and efficiency, reducing the fuel consumption (and CO2 emissions) by up to -50% and the direct operating costs by up to -30%. Since STERNA Hybrid Pack is the unique system natively designed for hybridization, it’s the only one that will bring you this level of economics for your aircraft operations, an easy integration into your aircraft, and a safe & certifiable approach.
STERNA Hybrid Pack can address aircraft ranging from turboprop commuter aircraft (typically 19 PAX) up to regional aviation (typically c. 70 PAX). Since Sterna Hybrid Pack is powering our hybrid-electric VTOL aircraft Atea, it can also match the specific performance requirements of other VTOL aircraft.
Yes. Our STERNA Hybrid Pack is optimized and designed as a whole to offer the best performance when equipped on an aircraft or VTOL, but we can provide parts of this Sterna Hybrid Pack if it fits your specific requirements.
Yes, our STERNA Hybrid Pack can be equipped in linefit on new generation of hybridized aircraft, and it can also be equipped in retrofit. We can help you develop this STC thanks to our expertise, our proprietary in-house test capability up to 1MW, and our “aircraft-maker DNA”.