NASA eVTOL drop test evaluates energy absorbing materials for safer future flights
August 6, 2025
As the FAA refines certification rules for eVTOL air taxis, crashworthiness has emerged as a critical safety challenge. NASA and industry players are now turning to advanced energy-absorbing materials to help close the gap between simulation and survivable reality.
NASA drops an eVTOL mock-up 35 feet to test energy-absorbing materials
In late June, NASA conducted a full-scale drop test at its Langley Research Centre to evaluate crashworthiness for next‑generation air taxis.
A mock‑up fuselage, complete with weighted dummies and simulated battery packs, was released from 35 ft and swung forward at a 10° yaw angle, replicating Federal Aviation Administration certification conditions for powered‑lift aircraft.
Inside, engineered energy‑absorbing subfloors functioned like crumple zones, deforming as intended and closely matching computer simulations refined from early tests in 2022.
“By showcasing elements of a crash alongside how added energy-absorbing technology could help make the aircraft more robust, these tests will help the development of safety regulations for advanced air mobility aircraft, leading to safer designs,” said Justin Littell, test lead, based at Langley.
Once analysed, NASA will share the data and insights with the public to enhance further research and development in this area.
Leading eVTOL developers are also testing energy-absorbing materials
The materials under test by NASA are designed to crumple on impact, absorbing and dissipating kinetic energy to reduce transmission to the occupants. More widely used in automotive than aviation, such materials can sometimes be found in seats, fuselages and landing gear.
The Sikorsky UH-60 Black Hawk has energy-absorbing landing gear, seats and a crushable floor. This enables it to meet stringent military crashworthiness standards and will save lives in a hard landing scenario.
In the eVTOL air taxi market, several of the most prominent air taxi development companies are also heavily researching energy-absorbing materials:
- Joby Aviation integrates crash energy management systems, including crush zones and shock‑absorbing substructures, validated via drop and sled testing
- Archer Aviation incorporates impact‑attenuating design elements into underfloor structures and battery mounts, based on safety engineering and FAA compliance planning
- Beta Technologies equips its Alia‑250 with energy‑absorbing seat supports and battery housing designs to limit deceleration forces transmitted to occupants.
- Wisk Aero and others explore hybrid composite layups, such as carbon‑aramid blends, and additive‑manufactured crush components for gear and fuselage elements
Under the FAA’s powered-lift certification, eVTOLs will need to prove crashworthiness, but the FAA admits that there are still some data gaps around real-world crash loads and aircraft arrangements. Testing from NASA and eVTOL developers will help to inform future refinements to the rules.
The latest on certification for eVTOL air taxis
The FAA Advisory Circular 21.17‑4, released in July, establishes design and performance airworthiness criteria specifically for powered‑lift aircraft, including eVTOLs. It draws from FAA parts 23, 27, and more, and offers a performance‑based compliance framework tailored to their unique crash safety requirements.
In parallel, the MOSAIC final rule expands the Light Sport Aircraft category to include powered‑lift aircraft. It removes outdated weight restrictions, allows consensus‑standard certification, and enables certified sport‑pilot flight under new performance‑based criteria, helping smaller eVTOLs enter service more easily.
The FAA requires eVTOL designs to withstand vertical, horizontal, and off‑axis crash loads typical of urban operations. Models like vertical impacts of up to 8 m/s and forward speeds of 25 m/s (up to 40 m/s) are being used as benchmark conditions in early studies.
Occupant protection must be validated through stroking seats, subfloor crush structures, and robust energy-absorbing landing gear. As testing continues to develop the understanding of the limitations and nuances of this new class of aircraft, rules will be refined to better reflect real-world risks.
