Universal Hydrogen Co. flew a 40-passenger regional airliner using hydrogen fuel cell propulsion - a world first for an aircraft of this type - on 2 March 2023. The plane, nicknamed Lightning McClean, took off from Grant County International Airport in Washington State and flew for 15 minutes, reaching an altitude of 3,500 Mean Sea Level. he flight, conducted under an FAA Special Airworthiness Certificate, was the first in a two-year flight test campaign expected to culminate in 2025 with the entry into passenger service of ATR 72 regional aircraft converted to run on hydrogen. In this first test flight, one of the airplane’s turbine engines was replaced with Universal Hydrogen’s fuel cell-electric, megawatt-class powertrain. The other remained a conventional engine for safety reasons. The flight was piloted by Alex Kroll, an experienced former U.S. Air Force test pilot and the company’s chief test pilot. “During the second circuit over the airport, we were comfortable with the performance of the hydrogen powertrain,” said Kroll ”so we were able to throttle back the fossil fuel turbine engine to demonstrate cruise principally on hydrogen power”. He added: “The airplane handled beautifully, and the noise and vibrations from the fuel cell powertrain are significantly lower than from the conventional turbine engine” The company has a rapidly growing order book, today totaling 247 aircraft conversions from 16 customers worldwide.