U.S. Federal Aviation Administration chief Steve Dickson warned on Tuesday of a changed industry in the wake of the COVID-19 pandemic that has shaken air travel over the past year and created new safety risks that must be addressed.

"The industry that existed last March in many respects no longer exists today," Dickson said at a town hall about commercial aviation safety shown on social media, citing the retirement of veteran pilots, new fleets with complex aircraft and less international flying.

"All these changes are creating a whole new set of stressors that can inject new safety risks into the system," he said.

While the risk of a fatal U.S. commercial aviation accident has fallen by 94% since 1997 thanks to improvements in aviation safety, Dickson said the industry must proactively curb new safety risks by understanding the pandemic's impact.

He cited added training and enhanced industry oversight as possible measures.

"COVID-19 has created a tremendous amount of disruption and change in our system with breathtaking speed," he said.

Airlines have parked jets and drastically reduced their workforce, mostly through early retirement programs, as they weather a sharp downturn in demand as a result of the pandemic.

Separately, Dickson said the agency was acting quickly to finalize a new emergency airworthiness directive that would require stepped-up inspections of all Boeing 777-200 airplanes with Pratt & Whitney PW400 engines after an engine failure on a United Airlines flight forced an emergency landing on Saturday.

(Reporting by Tracy Rucinski and David Shepardson; Editing by Richard Chang)