Author: Dominic Weeks

[Everett, WA & Kemble, UK] — ZeroAvia today announced that the Federal Aviation Administration (FAA) has published the special conditions for the company’s electric engine as a Final Rule to the Federal Register. This represents a major step towards type certification of ZeroAvia’s electric propulsion system and wider hydrogen-electric powertrain.

The special conditions advance ZeroAvia’s readiness to progress through the certification process following the FAA issuing G1 and P1 issue papers last year. It caps off a run of milestones with the respective regulators overseeing the company’s certification projects, including the UK CAA awarding the company Design Organization Approval in October last year.

Given the novelty involved in electric engines for aircraft, the special conditions contain the additional safety standards that the FAA Administrator considers necessary to establish a level of safety equivalent to that established by existing airworthiness standards. As the world’s only hydrogen-electric focused Design Organization Approval OEM, ZeroAvia has demonstrated it has the maturity, processes and procedures to provide confidence to regulators that it can comply with stringent requirements. 

[Kemble, UK & Everett, WA – December 22nd 2025] — ZeroAvia today announced that it has completed a further round of financing, led by Barclays Climate Ventures, Breakthrough Energy Ventures, Ecosystem Integrity Fund, Horizons Ventures, Summa Equity, and AP Ventures, with participation from the National Wealth Fund and the Scottish National Investment Bank.

With additional investment secured, ZeroAvia has extended its cash runway for the next two years and will continue to fully industrialize its hydrogen power and propulsion technology for the aviation and defense markets.  

The company is already supplying its SuperStack Flex modular fuel cell power generation system to the defense sector, and there is increasing interest in the systems for unmanned aerial vehicles. The dual-use potential is strong: ZeroAvia is also in active customer discussions with eVTOL and fixed-wing commercial players in relation to deploying the compact, lightweight, flexible systems. 

The SuperStack Flex can enable both electric propulsion and enhanced on-board electrical power generation with greater power density than battery systems. It unlocks all of the benefits of electrical operation – lower thermal and noise signatures, reduced maintenance costs, enhanced reliability and zero-emissions – and with significantly enhanced endurance. With Design Organisation Approval granted by the UK CAA in November, ZeroAvia is well positioned to deliver the first fuel cell systems for aviation with regulatory approvals. 

As well as a standalone power generation system with a wide variety of defense and civil applications, the SuperStack Flex is a core module of ZeroAvia’s first planned full hydrogen-electric powertrain, ZA600, designed for 10-20 seat commercial aircraft. With a prototype extensively flight tested, hundreds of engine orders in place with airline customers (including a launch customer), and funding in place to support the entry-in-service of 15 aircraft in Norway, ZeroAvia’s focus is now on pushing towards its first certification to support these opportunities.   

[Kemble, UK & Everett, WA – November 17, 2025] — ZeroAvia today announced that it has been awarded design organisation approval (DOA) by the UK CAA, a critical milestone on its path to certifying a hydrogen-electric engine intended for Part 23 aircraft. The accreditation confirms that the CAA is satisfied that ZeroAvia has the technical expertise, facilities and capabilities to design safe and reliable products, and is prepared to comply with stringent requirements for certification.

The award means that ZeroAvia has become the first company globally seeking to certify a hydrogen-electric aviation powertrain to receive DOA accreditation from a national regulator. The award confirms that a manufacturer is qualified to design and hold a type certificate for propulsion systems developed under commercial aviation regulations. These requirements are intended to ensure safe global market entry and have been adopted by other regulatory authorities, including EASA and the FAA. 

Securing DOA represents an essential enabler towards the company’s goal of securing a type certificate for its ZA600 – a 600kW powertrain which uses fuel cells to generate electricity from hydrogen, thus powering electric motors to turn aircraft propellers. Water vapour is the only emission from the engine, and it promises greater efficiency and reduced maintenance costs for airlines. 

Achieving DOA status follows two other significant regulatory milestones for ZeroAvia this year, with the U.S. Federal Aviation Administration issuing both G-1 and P-1 issue papers in relation to ZeroAvia’s bid to certify its 600kW electric propulsion system (EPS). The 600kW EPS is made up of the company’s proprietary motor and power electronics technology and is both an integral part of the overall ZA600 hydrogen-electric powertrain, and a power-source agnostic electric engine in its own right, with a range of applications. 

Earlier this year, ZeroAvia confirmed that RVL Aviation intends to be the first operator to fly the ZA600 engine in a Cessna Caravan 208b on cargo routes in the UK. The company is also working to scale the hydrogen-electric propulsion technology for larger segments of aircraft and has secured thousands of engine pre-orders with airlines across the world. 

The company has established a unique range of test facilities at its UK R&D and flight testing centre at Cotswold Airport, enabling an efficient testing programme to satisfy the means of compliance that it is in the process of agreeing with the CAA. After rigorous inspection of the facilities, interviews with ZeroAvia’s team and audit of its process, the CAA was able to award the DOA.  

[Kemble, UK & Bedford, UK – 10^th November 2025] — ZeroAvia and Hybrid Air Vehicles today announced that they have signed a Memorandum of Understanding to partner on development of a hydrogen-electric variant of Airlander 10.

Airlander 10 is a new type of hybrid aircraft that uses a combination of aerostatic lift, aerodynamic lift, and vectored thrust, with a 10 tonne payload and 4,000 nautical mile maximum range. The initial Airlander 10 will be powered by four diesel engines, providing an emissions reduction of up to 90% when compared with comparable capacity aircraft. Integrating ZeroAvia’s hydrogen-electric propulsion will deliver full zero-emission in-flight operations carrying 100+ passengers, as well as reduced maintenance costs.

ZeroAvia’s first generation 600kW hydrogen-electric powertrain – ZA600 – has already passed several regulatory milestones, secured hundreds of pre-orders and signed up launch customer airlines who are working to embed the system into more traditional fixed-wing aircraft for lower cost and more environmentally friendly flight. The company has conducted flight testing of a prototype on board a 19-seat aircraft.

With ample space for hydrogen storage in the hull, the Airlander represents an excellent option for adopting the first generation of certified hydrogen technologies that are already close to market entry: hydrogen storage, low temperature PEM fuel cell power generation and electric propulsion systems that are well advanced in the certification journey. This partnership will build on HAV’s earlier R&D work to explore electric propulsion for Airlander.

As part of the agreement, the companies will also study the potential applicability of ZeroAvia’s hydrogen-electric technology to future larger aircraft developed by Hybrid Air Vehicles, and assess planned Airlander 10 operations to define the hydrogen fuel infrastructure requirements.

[Kemble, UK & Everett, WA – October 15th, 2025] — ZeroAvia today announced that it has shipped its first flight intent SuperStack Flex modular low temperature proton exchange membrane (LTPEM) fuel cell system to a customer in the defense sector. The system has been fully qualified against the customer’s airworthiness requirements.

ZeroAvia’s SuperStack Flex is a modular fuel cell power generation system that can be configured to meet specific customer power needs while maintaining high power-to-weight ratio and highly flexible configuration.  

The lightweight, aerospace optimized balance-of-plant, has been developed to enhance the range of many Unmanned Air Vehicles (UAV), with further potential applicability across aerospace, maritime and ground use cases. The system can be used to provide propulsive power or to deliver enhanced onboard electrical capacity, opening up new capabilities in primary propulsion, auxiliary power systems and mission systems including ISR applications. The Superstack Flex is also an ideal system for the new FAA Mosaic Light Sport Category, providing more than enough power for a standard four-seater general aviation (GA) aircraft in this sector. 

The SuperStack Flex has demonstrated over 1.2kW/kg specific power and recently completed more than 100 hours of testing, consuming over 250 kg of hydrogen, and delivering continuous power at greater than 150 kW over long intervals, with peak power over 175 kW.   

Hydrogen and fuel cell technologies are becoming increasingly relevant to armed forces due to unique advantages in energy density, lower detectability thanks to reduced thermal and noise signatures, operational flexibility and lower maintenance costs. 

Using selective laser sintering (SLS) powder-bed additive manufacturing processes, ZeroAvia has been able to perform high velocity cycles of design, build and test, and quickly combine typical parts or their functions into new monolithic structures. The key parts in the SuperStack Flex’s balance of plant – Anode, Cathode and Coolant Manifolds, thermal management, humidification and air compression systems – have been reduced from over 200 parts to less than 100, with ~50% weight and volume reductions. Fewer parts mean lighter, more compact, more reliable and less costly systems.    

In the final stages of testing, the system was providing power back to ZeroAva’s Propulsion Center of Excellence in Everett, generating enough power to offset the entire building’s consumption. 

 [Everett, WA: August 19th, 2025] — ZeroAvia today announced that it has reached consensus with the Federal Aviation Administration (FAA) with an agreed and fully signed P-1 Special Conditions Issue Paper regarding certification of its 600kW electric propulsion system (EPS). 

The P-1 follows issuance of the FAA G-1 in February 2025 and documents the special conditions applicable to ZeroAvia’s novel electric propulsion technology to be addressed in the certification process with the U.S. regulator. Once the FAA’s Special Conditions rule is finalized and published in the Federal Register, the means of compliance for the innovative EPS meeting those conditions will be determined in the next certification stage.  

Progressing from the G-1 to the P-1 marks another milestone both on the journey toward certification of ZeroAvia’s EPS with the U.S. regulator, and also on the path toward certifying the company’s first fully hydrogen-electric powertrain with the UK Civil Aviation Authority.  

ZeroAvia’s 600kW EPS combines the company’s proprietary inverter and electric motor technology to deliver a highly efficient electric engine with exceptional fault tolerance and specific power. The 600kW EPS system comprises four ZeroAvia 200kW continuous power bidirectional inverters converting DC power to AC to supply ZeroAvia’s direct drive motor, capable of 2,200 rpm.  

ZeroAvia launched a component offering in May 2024 to serve the market for novel electric air transport applications. Potential applications for the 600kW EPS include battery, hybrid and fuel cell electric fixed-wing aircraft, rotorcraft and unmanned aerial vehicles (“UAV’s”).   

The electric propulsion system is one part of ZeroAvia’s deep portfolio of hydrogen and electric aviation technology, resulting from the company’s strong commitment to vertical integration. ZeroAvia’s complete ZA600 hydrogen-electric powertrain, designed for up to 20-seat commercial aircraft, combines the EPS with a hydrogen fuel cell power generation system (“PGS”).  

ZeroAvia has already tested a prototype of the ZA600 hydrogen-electric engine aboard a Dornier 228 aircraft at its UK base. The company also has an engineering partnership with Textron Aviation as it looks to secure a supplemental type certificate for the Cessna Grand Caravan as the launch airframe for the ZA600. And in May, the company announced RVL Aviation as its UK launch customer for the world’s first hydrogen-electric commercial service route.    

[Everett, WA & Kemble, UK July 17, 2025] — ZeroAvia today announced that it has been awarded nine new patents this year so far, with many critical to the company’s roadmap for scaling hydrogen-electric engines for large regional aircraft. The company has now been granted a total of 45 patents related to hydrogen and electric aviation systems, with almost 250 applications, most of which are still going through the patent office pipelines.  

United States Patent and Trademark Office (USPTO) no. 12,341,225 covers an integrated hydrogen-electric engine and is key to the development of a modular multi-MW hydrogen-electric engine for ATR and Dash 8 families of aircraft. The design concept relates to ZeroAvia’s ZA2000 engine for 40-80 seat regional turboprops and jets, with advanced and novel integration concepts creating a tightly packaged, power-dense zero-emission aircraft engine.  

Also important for scaling hydrogen-electric engines for large aircraft is the delivery of fuel cell systems with higher specific power. UK patent office GB2614450 covers novel coatings for aluminium bipolar plates for high temperature PEM (HTPEM) fuel cell systems, allowing the higher temperature operation with lightweight metals, while overcoming material degradation challenges.  

Other patents granted cover key innovations in cryogenic management systems, thermal management for fuel cell systems and fuel cell catalysts using platinum nanoparticles. One relates to a refueling system for hydrogen fuel cell-powered aircraft that enables both efficient refueling and employs a thermoelectric generator to leverage the heat from the refueling process to provide electricity for other aircraft systems.  

ZeroAvia’s granted patent portfolio now includes key coverage across all key subsystems of the engine and aspects of aircraft integration. With the addition of the robust set of trade secrets, especially in the areas of material innovations related to ZeroAvia’s unique HTPEM fuel cell systems, the company now boasts one of the most advanced IP portfolios in hydrogen-electric aviation powertrain technology.  

With both Airbus and Boeing advancing plans and IP for hydrogen-ready airframes in recent weeks, securing IP on engine systems is a key building block for aspiring clean engine manufacturers for the aircraft of the future. Building a strong IP portfolio has been an integral part of ZeroAvia’s strategy since inception, with high-levels of in-house development of core systems enabling rapid progression through design gates and creating additional commercial opportunities beyond the primary commercial aero engine market.  

[@Paris Air Show: June 17th, 2025] — ZeroAvia today announced the UK Government has awarded the company and consortium partners a grant towards a £10.8m project to develop a novel liquid hydrogen management system. The project, co-funded through the ATI Programme, will culminate in integration of the lightweight fuel system into a Dornier 228 before a series of flight tests.  

The Liquid Hydrogen System Integration & Flight Test (LH-SIFT) project will rapidly develop a Liquid Hydrogen Management System (LHMS) and create an adaptable flight testbed capability. The testbed capability will benefit UK and global LH2 supply chains in maturing liquid hydrogen technologies faster. 

The LH2 management system developed as part of LH-SIFT is comprised of a novel lightweight metallic tank design and supporting systems for filling and managing storage and distribution. Consortium partners Green Resource Engineering and Gas & Liquid Controls will collaborate with ZeroAvia on fill, feed, vent and vaporiser systems.  

The project will also establish the world’s first liquid hydrogen flying commercial airframe testbed, providing unique opportunities for later projects to develop and test cryogenic aviation fuel system components in flight, building strong UK leadership in this area.  

ZeroAvia is advancing certification of a 600kW hydrogen-electric powertrain for 10-20 seat planes using gaseous hydrogen fuel. However, the company is also developing the next generation of fuel cell aircraft engines with its ZA2000 for 40-80 seat aircraft, and supporting other high-power use cases through its component offering. To support these aircraft’s typical missions, it is necessary to transition to liquid hydrogen fuel storage – storing fuel at cryogenic temperatures around -253°C – which enables more energy by volume. In addition to fueling larger aircraft platforms, smaller zero-emissions aircraft can also benefit from using liquid hydrogen to extend their capability. 

[Kemble, UK & Everett, WA, USA: May 13th, 2025] — ZeroAvia today announced that it has signed an agreement with RVL Aviation which will see RVL operate Cessna Grand Caravan aircraft retrofitted with ZeroAvia’s hydrogen-electric, zero-emission ZA600 powertrain. Flights within the British Isles will commence once certification for the engine, airframe integration and planned services are obtained and all retrofit and training work is complete.   

Analysis performed by RVL and ZeroAvia confirms that the ZA600-enabled Cessna Caravan would meet existing operational requirements while virtually eliminating the climate impact of the operations. There are nearly 1,000 aircraft operating cargo routes around the world today that could in future be powered by ZA600 powertrains.   

This current agreement focuses on one type of aircraft, Cessna Caravan 208B, with RVL working with zero-emission specialist MONTE on the aircraft lease. The partners will explore opportunities to launch further small turboprop operations in the growing RVL network based on the success of the initial operations, as well as expand the technology across its other operations when the technology and operating conditions permit.  

RVL Aviation is a specialist aviation services provider with more than 40 years of experience. The company and its skilled people deliver their expertise to a wide range of Government and private sector organisations, helping to support economic and environmental prosperity agendas. RVL Aviation is headquartered at East Midlands Airport, operating primarily from its hangar and maintenance facility, and its capabilities include airborne survey, aerial surveillance, aerial dispersant services and aircraft charter. 

ZeroAvia’s hydrogen-electric engines use hydrogen in fuel cells to generate electricity to power electric motors that turn propulsors, with the only byproduct being water. Analysis suggests that switching to fuel cell propulsion can provide an overall climate impact reduction in the region of 90%.¹ Further, hydrogen-electric propulsion can reduce overall operating costs for carriers due to the lower requirement for maintenance and lower fuel costs in the scaled operations.