By David Shepardson

WASHINGTON (Reuters) -The fired vice chair of the U.S. National Transportation Safety Board sued President Donald Trump on Wednesday, saying his removal from office was illegal and threatened the independent agency's safety mission.

Alvin Brown, a Democrat who was the first-ever African American elected mayor of Jacksonville, Florida, was designated as vice chair in December by then-President Joe Biden after he joined the five-member board in March 2024. Reuters first reported his May 5 removal from office by the White House.

Brown's lawsuit filed in U.S. District Court in Washington also names the NTSB and NTSB Chair Jennifer Homendy, seeking a court order to enable him to perform his duties as a board member and "to ensure that the NTSB can resume its congressionally mandated work as Congress intended."

The lawsuit added his removal has "significant and damaging consequences for the work of the Board and its investigation and reporting of major transportation accidents and casualties."

The NTSB declined to comment. The White House did not immediately respond to a request for comment.

The NTSB investigates all civil aviation accidents as well as significant accidents in other modes of transportation - highway, marine, pipeline and railroad - and determines the probable cause and makes safety recommendations.

Brown's suit said Trump may remove a board member "only for inefficiency, neglect of duty, or malfeasance in office."

A lawyer for Brown, Victoria Nugent, said "at a time when transportation safety is top of mind, we should be strengthening, not weakening, the systems meant to protect all Americans."

Since January, Trump has fired two Democratic members of the Federal Trade Commission and members of the National Labor Relations Board, Merit Systems Protection Board and Federal Election Commission among others.

The U.S. Supreme Court last month allowed Trump's firing of two Democratic members of federal labor boards to remain in effect while their legal challenges proceed, in a dispute that tests his power over independent government agencies.

Brown's removal from the NTSB came amid heightened concern about aviation safety following the January 29 mid-air collision of a U.S. Army helicopter and an American Airlines regional jet that killed 67 people.

Transportation Secretary Sean Duffy wants tens of billions of dollars from Congress to overhaul U.S. air traffic control and staffing.

(Reporting by David Shepardson; Editing by Jamie Freed)