The head of the world’s busiest airport has been let go by Atlanta mayor Kasim Reed.

Miguel Southwell, general manager of Hartsfield-Jackson International Airport, will no longer lead the airport. In a written statement late Friday evening, Reed said Southwell’s “service as Aviation General Manager at Hartsfield-Jackson Atlanta International Airport has ended.”

Reed said he is “committed to achieving maximum operational efficiencies and the highest level of customer service possible. I wish Mr. Southwell the best in the next chapter of his career.”

Roosevelt Council, the airport’s chief financial officer and deputy general manager, will serve as interim general manager of the airport.

The move comes as the Atlanta airport is surrounded by some of its biggest controversies in recent years, while also preparing to launch a massive expansion project.

Hartsfield-Jackson has been in the spotlight for weeks over long security lines, under pressure to fix the issue with the Transportation Security Administration. Long wait times at TSA checkpoints have plagued the Atlanta airport for a year, but have worsened recently, while cropping up at other airports around the country.

At Hartsfield-Jackson, the crowds had become such a sore point that Southwell and his team decided to change the airport’s tagline from “world’s busiest” to “world’s most traveled” — saying “busy” had a negative connotation.

Southwell wrote a letter to TSA earlier this year threatening to consider privatizing airport security screening if the issue was not addressed. TSA administrator Peter Neffenger pledged to add staff and test new systems in Atlanta to help speed screening.

Construction this month to build “smart lanes” that use RFID radio frequency identification technology and automated conveyor belts to move bins around more quickly for a pilot project has led to even longer lines that stretch into baggage claim and fill the terminal.

The smart lanes are expected to be complete by Tuesday, but the project is in crunch time to finish preparations in time for the re-opening — just days before an influx of hundreds of thousands of passengers over Memorial Day weekend and the kickoff of a very busy summer that could bring big crowds and long waits.

The airport is also enmeshed in a controversial political battle, in an effort to legalize and regulate pickups at the airport by Uber X ride-sharing drivers.

Southwell said in March that he intended to allow legal Uber X and Lyft ride-share pickups by July 1 and proposed a plan to do so, including a requirement for fingerprint-based background checks. But vociferous objections from Uber and Lyft and the threat that those companies would not operate at the airport under Southwell’s proposed rules have led the Atlanta City Council to hold the measure for more discussion.

Meanwhile, Hartsfield-Jackson is also preparing to tackle a $6 billion, 15-year expansion project to add Concourse G, build a sixth runway, renovate the terminal, tear down and expand parking garages, and build a hotel at the airport along with a service station and commercial office space, among other projects.

The hotel project, originally expected to move forward by the end of 2015, was delayed and construction has not yet started.

The renovation of the terminal and parking garage project in coming months and years will make the airport into a construction site, creating hassles for travelers at the same time as the airport handles long security lines and record-breaking crowds of passengers.

Hartsfield-Jackson recently signed a 20-year lease with Delta Air Lines, cementing that relationship between the city of Atlanta and its hub carrier.

But Delta is also in the middle of battling incoming foreign competitors expanding at Hartsfield-Jackson, with Qatar Airways preparing to launch operations at the airport June 1. Turkish Airlines also started flights to Atlanta this month.

Under Reed, airport leaders have had relatively short tenures before being replaced by an interim manager.

Southwell had been on the job for two years, tapped for the top job at the airport in May 2014. He took on the position then at the age of 58 for a $221,000 salary.

At the time, Reed called Southwell “the right executive to continue Hartsfield-Jackson’s dominance.”

Southwell came from Miami, where he was a deputy airport director, but he was no stranger to Atlanta. He started as an intern at the Atlanta airport and worked his way up from 1990 to 2001 to become interim assistant general manager of business and finance, before leaving for Miami.

Southwell rejoined Atlanta as a deputy general manager in 2013, then was named interim general manager, before getting the permanent appointment to the top job.

He had at that point already been a potential candidate for the top spot in 2010, after the departure of longtime airport manager Ben DeCosta.

DeCosta had been the top executive at Hartsfield-Jackson for 11 years, but had contentious relations with Delta during lease negotiations, and was on his way out shortly after Reed took office in 2010.

Louis Miller from Tampa was named as his successor, and lasted three years before retiring.

When Southwell was named interim general manager, he hit the ground with ambitious plans to continue work to expand the airport and add international flights.

As Reed gave him the permanent job leading the Atlanta airport, the mayor said in a written statement: "His experience in Miami, and prior experience in Atlanta, is the right fit to carry out my vision for our airport to be the nation's leader in the logistics and air cargo space."

But now, Southwell’s successor will face the challenges of continuing the airport’s rapid growth, figuring out how to fix immediate issues including long security lines and working through political battles.

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