ZeroAvia, an advanced propulsion developer, has announced its intention to convert a Dornier 228 testbed into a liquid hydrogen test vehicle. Initially modified to run on gaseous hydrogen, the aircraft successfully completed several test flights using an electric motor and fuel cell system. The upcoming conversion will involve replacing the gaseous hydrogen tanks with liquid hydrogen storage at extremely low temperatures. ZeroAvia is also preparing another Dornier 228 as a testbed for its ZA600 powertrain. Ground testing of the electric propulsion system is currently underway in Washington state, with plans to integrate it with a Cessna Grand Caravan. The company aims for UK Civil Aviation Authority certification by 2026, followed by service entry in 2027. This development signifies a positive step towards sustainable aviation technology, combining innovation with environmental responsibility.