Who Is Liable for a Battery Fire? Which Airport Can Refuel a Hydrogen Aircraft? And Who Will Certify the Aircraft of the Future?

The aviation industry is approaching one of the most significant technological transformations in its history.

For approximately a century, petroleum-based fuels have powered commercial aviation. Today, however, battery-electric propulsion, hydrogen fuel cells, liquid hydrogen combustion and hybrid-electric propulsion systems are emerging as potential alternatives to conventional aircraft technologies.

This transformation is not merely an engineering challenge.

Replacing a conventional aircraft engine with an electric or hydrogen propulsion system may affect almost every major component of aviation law, including aircraft certification, airport regulation, product liability, insurance, aircraft finance, energy regulation and environmental law.

ICAO has adopted a long-term global aspirational goal of achieving net-zero carbon emissions from international aviation by 2050, with aircraft technology, operational improvements and cleaner aviation energies forming part of the broader decarbonisation strategy.

Accordingly, the principal question of the coming decades will no longer simply be:

“Can electric and hydrogen aircraft fly?”

The more important legal question will be:

“Under which legal and regulatory framework can they fly safely and commercially?”

1. Electric Aircraft and the Challenge to Traditional Airworthiness Law

Electric aircraft use electric motors instead of conventional combustion or turbine propulsion.

Electricity may be supplied directly through batteries or generated through hybrid systems and hydrogen fuel cells.

Traditional aircraft certification rules, however, were largely developed around piston engines and gas turbine technology.

Electric propulsion introduces entirely different concepts into aviation safety regulation:

high-voltage electrical architecture,

battery packs,

thermal runaway,

electrical energy storage,

battery management systems,

inverters,

electric motors,

electromagnetic compatibility,

charging infrastructure,

battery degradation.

Consequently, simply applying traditional engine certification requirements to electric propulsion technology may not always provide an adequate regulatory solution.

EASA developed Special Condition SC E-19 – Electric/Hybrid Propulsion System specifically to address electric and hybrid propulsion architectures and to provide sufficient flexibility for technological innovation while maintaining an equivalent level of aviation safety.

This represents an important conceptual change.

Future aircraft certification will increasingly require regulators to evaluate not merely an “engine”, but the entire chain through which energy is:

stored → managed → distributed → converted → delivered to propulsion systems.

2. How Will an Electric Aircraft Obtain Type Certification?

Before an aircraft can enter commercial operation, its design must comply with the applicable airworthiness requirements.

Within the European aviation system, Regulation (EU) 2018/1139 and the EASA certification framework establish fundamental aviation safety and environmental requirements.

Electric aircraft, however, raise entirely new certification questions.

For example:

What happens if a battery cell enters thermal runaway during flight?

Can a single battery-cell failure propagate throughout an entire battery pack?

What redundancy is required following the complete loss of an electrical propulsion channel?

How should battery temperature be controlled?

At which level of battery degradation does an aircraft cease to satisfy continuing airworthiness requirements?

How should battery cycle life be incorporated into mandatory maintenance programmes?

These questions are likely to become central to twenty-first-century airworthiness law.

3. Certification of Electric Aircraft in Türkiye

Türkiye also possesses an increasingly developed national aircraft certification framework.

The SHY-21 Regulation on Airworthiness and Environmental Certification of Aircraft and Related Products, Parts and Appliances, published on 28 April 2025, together with its implementing rules, forms an important component of Türkiye’s current certification system.

On 2 July 2026, the Turkish Directorate General of Civil Aviation published SHT-21 Revision 02, establishing updated procedures and principles for implementing SHY-21.

EASA Certification Specifications also play an important reference role within Turkish certification practice. Recent Turkish certification activity demonstrates the use of relevant EASA certification specifications when establishing certification requirements.

Accordingly, certification of future Turkish electric or hydrogen aircraft would likely involve the existing SHY-21/SHT-21 framework together with technology-specific certification requirements and developments originating from international and European aviation authorities.

4. Hydrogen Aircraft: An Even Greater Regulatory Challenge

Hydrogen represents another major pathway towards aviation decarbonisation.

Hydrogen may broadly be used in two different ways.

First, hydrogen fuel cells may generate electricity that powers electric motors.

Second, hydrogen may be burned directly in specially designed combustion engines.

Both approaches create significant regulatory challenges.

Hydrogen storage differs substantially from conventional aviation fuel storage.

Liquid hydrogen technologies may require:

cryogenic storage,

new tank architecture,

hydrogen leak detection,

specialised ventilation,

fire protection,

explosion protection,

new fuel distribution systems.

Recognising these challenges, EASA has launched a Hydrogen Certification Roadmap designed to identify certification gaps, determine whether existing Certification Specifications remain sufficient and establish a coordinated regulatory approach towards hydrogen-powered aviation.

This demonstrates a fundamental reality:

The success of hydrogen aviation depends not only on developing the technology, but also on developing a legal system capable of certifying that technology.

5. Who Will Be Liable When a Hydrogen or Electric Aircraft Accident Occurs?

Electric and hydrogen propulsion technologies may fundamentally change aviation accident litigation.

Imagine an aircraft battery fire.

The cause could potentially be:

a defective battery cell,

defective battery-management software,

an aircraft design defect,

incorrect maintenance,

an airline’s failure to follow maintenance procedures,

or malfunctioning airport charging infrastructure.

A single accident could therefore involve an extraordinarily complex liability chain:

Aircraft Manufacturer → Battery Manufacturer → Software Developer → Maintenance Organisation → Airline → Airport Energy Operator

International passenger liability may simultaneously arise under the Montreal Convention, while recourse claims between the airline, manufacturer, maintenance organisation and component suppliers may depend upon separate contractual and product liability regimes.

Future aviation litigation may consequently move far beyond the traditional relationship between passenger and airline.

6. When the Battery Becomes as Important as the Aircraft Engine

In an electric car, a battery is an important component.

In an electric aircraft, the battery may become an essential component of flight safety.

Battery manufacturers may therefore acquire a considerably more important legal position within the aviation supply chain.

Future Aircraft Purchase Agreements and supply contracts may increasingly contain sophisticated provisions concerning:

Battery Performance Warranties

Minimum Capacity Guarantees

Cycle-Life Guarantees

Thermal Runaway Protection

Replacement Obligations

Battery Degradation Thresholds

Battery Management System Liability

Recall Procedures

Consider an aircraft battery expected contractually to remain commercially usable for 5,000 cycles but falling below the required capacity after only 2,000 cycles.

The resulting dispute might involve far more than replacement of the battery.

It could include:

fleet grounding, replacement aircraft costs, loss of revenue and consequential damages.

The battery could therefore become one of the most heavily negotiated assets in future aircraft transactions.

7. Airports May Become Energy Hubs

The transition towards electric and hydrogen aviation will not stop at the aircraft.

Airports themselves will need to change.

Electric aviation may require:

high-power aircraft charging stations,

airport-scale electricity storage,

grid upgrades,

specialised fire protection systems.

Hydrogen aviation may require:

hydrogen production or delivery,

cryogenic storage facilities,

specialised refuelling systems,

hydrogen leak detection,

explosion-protection zones.

ICAO already identifies onboard storage, safety, hydrogen production costs and the need for dedicated airport infrastructure as significant issues affecting the potential future commercial use of hydrogen in aviation.

Airport law may therefore increasingly become intertwined with energy law.

Energy infrastructure could become as important to airport regulation as runways and terminals.

8. What Happens If Airport Charging Infrastructure Causes an Aircraft Accident?

Consider an electric aircraft charged at an airport before departure.

A malfunction in the airport charging equipment damages its battery.

Several hours later, the damaged battery experiences thermal runaway during flight.

Who is liable?

The airport operator?

The charging infrastructure provider?

The electricity supplier?

The battery manufacturer?

The aircraft manufacturer?

Or the airline?

The answer may depend heavily upon contractual provisions relating to:

indemnities, liability caps, insurance, warranties, consequential losses and risk allocation.

Future Airport Services Agreements and Ground Handling Agreements may therefore need detailed provisions governing electric charging and hydrogen infrastructure.

9. If Hydrogen Is Not “Green”, Is the Aircraft Really Sustainable?

This may become one of the most important environmental-law questions surrounding hydrogen aviation.

An aircraft may produce little or no carbon dioxide during operation, yet the hydrogen it uses could have been produced through carbon-intensive processes.

Consequently, regulators are increasingly interested not merely in emissions produced by an aircraft itself, but in the life-cycle emissions associated with the energy it consumes.

The European Union’s ReFuelEU Aviation framework has already incorporated specific treatment for renewable hydrogen and low-carbon hydrogen in the broader regulation of cleaner aviation energies and lifecycle greenhouse-gas savings.

The legal question of the future may therefore not be:

“Does the aircraft emit carbon?”

but instead:

“How was the energy powering the aircraft produced?”

10. Will Electric Aircraft Eliminate Aviation Environmental Regulation?

No.

Even if battery-electric aircraft produce no direct carbon dioxide emissions during flight, environmental impact does not end at the aircraft exhaust.

The legal analysis may increasingly include:

the source of electricity,

critical minerals used in batteries,

battery manufacturing,

battery recycling,

end-of-life disposal,

energy storage infrastructure.

Hydrogen raises comparable questions concerning its method of production.

Consequently:

carbon accounting, lifecycle assessment, renewable-energy certification and environmental claims

may become important components of aviation regulation.

11. Could “Zero-Emission Flight” Advertising Trigger Greenwashing Litigation?

Imagine an airline advertising:

“This flight is completely environmentally friendly.”

or:

“Zero-emission aviation.”

An aircraft producing no operational carbon emissions does not necessarily mean that the electricity or hydrogen powering it was produced without emissions.

Environmental advertising therefore creates potential questions under:

consumer protection,

advertising regulation,

environmental law,

ESG compliance.

Airline sustainability statements may increasingly require legal review rather than being treated simply as marketing language.

12. Quieter Aircraft Could Transform Airport Regulation

Electric propulsion may also offer significant reductions in aircraft noise.

Both ICAO and EASA environmental policy encompass not only carbon emissions but also other environmental impacts, including aircraft noise. ICAO’s 2026–2050 Strategic Plan expressly combines the net-zero objective with goals relating to reducing aviation noise and emissions.

This may eventually influence:

night-flight restrictions,

noise quotas,

airport operating hours,

airport capacity,

regional air mobility,

urban air mobility.

The environmental advantages of electric aircraft could therefore have regulatory consequences extending well beyond climate law.

13. How Will Electric and Hydrogen Aircraft Be Insured?

Every revolutionary technology creates an “unknown risk” problem.

Insurers possess decades of historical failure data for conventional jet engines.

Comparable historical datasets do not yet exist at the same scale for new-generation hydrogen and battery-electric commercial aircraft.

Insurance policies may therefore increasingly have to address risks including:

battery fires,

thermal runaway,

hydrogen leakage,

charging infrastructure failures,

software malfunction,

cyber incidents,

prototype technology.

Aircraft hull insurance, aviation liability insurance and aviation product liability markets may need to adapt to these new risk profiles.

14. Software May Become as Important as the Engine

An electric propulsion system does not consist merely of a battery and motor.

Battery management systems, inverters and energy distribution architecture are extensively software-controlled.

Consequently:

a software defect may become an aviation safety defect.

An algorithmic error that causes battery cells to be overcharged could generate substantial product liability and airworthiness concerns.

Software developers may therefore increasingly become important actors in aviation product liability disputes.

15. Cybersecurity Will Become Part of Airworthiness

Digitalisation of electric aviation also creates cybersecurity risks.

Aircraft charging systems, battery management systems and airport energy infrastructure may all be connected to digital networks.

A malicious attack capable of:

altering battery charging parameters,

disabling energy-management systems,

manipulating pre-flight battery information

could create significant aviation safety consequences.

Future airworthiness standards will therefore increasingly have to consider cyber resilience together with physical safety.

16. Electric Aviation May Create a New Aircraft Finance Model

Aircraft finance may also change.

Under traditional aircraft financing structures, the aircraft’s airframe and engines represent the principal high-value assets.

Electric aviation may create another major asset:

the battery.

This could eventually produce financing structures such as:

Aircraft Lease + Separate Battery Lease

The battery could potentially be owned by a third-party financing entity while the airline pays for its use, replacement or capacity.

This would create new legal questions regarding:

ownership,

security interests,

leasing,

insolvency,

insurance,

battery replacement.

Aircraft finance lawyers may therefore need to rethink traditional asset structures.

17. Could Electric Aircraft Challenge the Cape Town Convention Model?

The Cape Town Convention and Aircraft Protocol play a fundamental role in international aircraft finance.

However, future aircraft may distribute economic value differently from the traditional:

airframe + aircraft engine

structure.

If a modular battery system becomes worth several million dollars, should it legally be treated as:

an aircraft component,

a separately financeable asset,

part of the aircraft object,

or independent collateral?

Similar questions could arise with high-value hydrogen fuel-cell systems.

As aircraft architecture changes, international aircraft-finance law may eventually need to reconsider how aviation assets are legally classified.

18. TOWARDS 2050: A NEW ERA OF AVIATION LAW

ICAO’s net-zero target for international aviation by 2050 is accelerating not merely technological change, but legal change throughout the aviation industry.

As electric and hydrogen aircraft move towards wider commercial use, areas including:

aircraft certification,

product liability,

airport regulation,

energy law,

environmental law,

aviation insurance,

aircraft leasing,

aircraft finance,

cybersecurity,

consumer protection

will increasingly intersect.

Sustainable aviation law will therefore not simply become a subcategory of environmental law.

It is developing into a broader legal discipline governing the entire life cycle of next-generation aircraft: from design and certification to financing, airport energy infrastructure, commercial operation, insurance and accident liability.

The defining question of the coming decades may therefore be:

As engineers redesign the future of flight, can aviation law evolve quickly enough to keep the new generation of aircraft safely in the sky?