Understanding the mechanisms that lead to thunderstorms and lightning remains one of the unsolved challenges in atmospheric science – with direct implications for aviation safety, aircraft design, and future propulsion technologies.
A recently launched project, ELECTRI-FLY (atmospheric ELEctricity and Charging characterization ThRough In-Flight measurements), seeks to address this critical knowledge gap through an ambitious in-flight research campaign.
Coordinated by France’s ONERA, the four-year program is under the umbrella of the International Forum for Aviation Research and also brings together researchers from NASA, JAXA, NRC, NLR. They will carry out coordinated airborne measurements of cloud electrification and microphysical processes across Europe and North America.
While lightning strikes are a routine hazard for aviation – each commercial aircraft is struck about once per year – the industry still relies heavily on avoidance strategies and robust shielding to mitigate risk. For future electric and hydrogen aircraft, which may be more sensitive to atmospheric electrical effects, improving understanding of lightning is critical.
The project addresses two key gaps in the current body of knowledge. Previous studies have explored cloud electrification from the ground or via remote sensing, but very few have successfully measured the electric fields and particle-level charges inside active storm clouds, insitu. Such data are essential to constrain physical models of charge generation and lightning initiation.
In addition it will couple this with cloud microphysics. Charging processes depend heavily on the presence and behavior of different hydrometeors, such as graupel, ice crystals and supercooled droplets. However, electrical and microphysical measurements are rarely obtained simultaneously with sufficient resolution. ELECTRI-FLY is specifically designed to overcome this limitation.
To tackle these challenges, NLR’s Cessna Citation II and NRC’s Convair-580 research aircraft will be equipped with advanced sensors and flown through electrically active clouds. These scientific flights will be conducted over
Europe in 2026 and 2027 and North America between 2027 and 2029, providing geographically diverse data sets.
Central to the project are two sensors developed by ONERA – AMPERA and AHDEL, which will measure atmospheric electric fields and the charge carried by individual particles in real time. AHDEL can quantify the distribution and polarity of charged particles, something rarely achieved in flight.
The aircraft will also carry microphysics probes to assess cloud structure, including droplet size, type, concentration, and ice content. The combination of these measurements will offer a multidimensional view of storm dynamics and electrification processes at unprecedented resolution.
The sensor data will be processed and compiled into a reference atmospheric database for researchers. The dataset will help to improve physical models of cloud electrification and lightning initiation, and support the development of predictive tools for storm activity and lightning risk.
The database will also be used to validate and refine atmospheric simulation models used in aviation risk assessment, trajectory planning and safety systems for conventional and emerging aircraft and improve the understanding of lightning-related NOx production and its environmental impact. Additionally ELECTRI-FLY will help mature next-generation airborne instrumentation for future operational use.
With the aviation sector shifting toward more sustainable propulsion systems and facing pressure to improve resilience to weather-related disruptions, ELECTRI-FLY offers timely and actionable insights. By bringing together leading aerospace agencies and leveraging coordinated flight campaigns, the project exemplifies how international collaboration can tackle scientific challenges that are global in scale and complexity.
