]The U.S. Federal Aviation Administration is in one of the most demanding periods in its history as it grapples with controversial new 5G mobile phone service, the fallout from twin Boeing Co. 737 Max tragedies and the Covid-19 pandemic.

Now the agency must contend with the potential of operating without a confirmed leader. 

The surprise announcement last month that its administrator is leaving at the end of this month has come as partisan conflict in the Senate has stalled all transportation-related nominees. Its architect, Florida Republican Senator Rick Scott, has vowed to continue the block until his demands for a hearing on the nation’s supply-chain issues are met, his spokeswoman said. 

“The aviation community and the FAA needs continuity, needs clarity and strong leadership,” said Hassan Shahidi, president and chief executive officer of the nonprofit Flight Safety Foundation. “It is important to have that strong leadership from the top and to do it quickly and without delay.”

FAA Administrator Steve Dickson on Feb. 16 announced that he was stepping down about halfway into his five-year term. 

Transportation Secretary Pete Buttigieg told reporters March 2 at the Capitol that a nominee would come “soon.” Numerous names have been floated by lawmakers, unions and the news media, but the administration hasn’t signaled whether it has narrowed its choice toward any of them. 

According to four people who follow the FAA and aviation industry but asked not to be identified discussing the sensitive pick, the list of possible nominees include: 

Chesley “Sully” Sullenberger, the hero pilot who became the ambassador to the International Civil Aviation Organization earlier this year; John Boccieri, a United Airlines pilot who served in Congress; Deborah Hersman, the former head of the National Transportation Safety Board; Katie Thomson, the FAA’s former chief counsel who recently became the DOT’s director of implementation for the new infrastructure program; Lee Moak, a former president of the Air Line Pilots Association union who founded a consulting firm; and FAA’s current Deputy Administrator Bradley Mims, who served as president of the Conference of Minority Transportation Officials.

The Allied Pilots Association, which represents American Airlines’ cockpit crews, recently endorsed Boccieri for the job, as well as David Bourne, director of the Teamsters Airline Division; and Joe DePete, president of the ALPA union. 

The FAA in the past few years has undergone one crisis after another: the grounding of the 737 Max, a global pandemic that cut airline travel by 95% and a surge in violence on airline flights. 

The agency has just begun implementing reforms ordered by Congress in the wake of the 737 crashes. It’s continuing to work with wireless companies’ to limit 5G towers near airports. 

The Flight Safety Foundation’s Shahidi said it’s not enough to have an acting administrator leading FAA. “The country needs to have, clearly for aviation safety, a permanent person at the top,” he said in an interview.  

Senator Maria Cantwell, the Washington Democrat who is chairwoman of the Commerce Science and Transportation Committee, said last week she expects the pick to be announced by the end of the month. 

But Cantwell and Scott have tangled for months over Scott’s demands to call Buttigieg and Commerce Secretary Gina Raimondo to testify on supply chain issues. 

“We’ve been very frustrated,” Cantwell said when asked about Scott’s actions. 

“Senator Scott’s holds and prior statement still stand,” Scott spokeswoman Clare Lattanze said in an email. “FAA would fall under the purview of his holds.”