The letter, obtained from a source by Aaron Diamant of Atlanta's WSB-TV, was dated February 12. The TSA confirmed to Business Insider that it has received the letter and is evaluating it.
In the letter, Southwell says the chronic staffing shortages are leading to wait times of over half an hour at the TSA checkpoints. If things don't change, the airport will bring in private security personnel under the TSA's Screening Partnership Program, he warns.
"Several times throughout the day from May to October 2015, wait times (at TSA checkpoints) exceeding 35 minutes were not uncommon," Southwell wrote. "This is unacceptable as reflected in the customer service surveys of our hub carrier Delta Air Lines."
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36. YVR - Vancouver International
A traveler arrives at Vancouver International Airport (YVR) in Richmond, British Columbia, Canada, on Wednesday, Nov. 13, 2013. The number of international visitors to Canada plunged 20 per cent since 2000 even as global travel soars, according to a sobering report being released Thursday by Deloitte Canada. Photographer: Ben Nelms/Bloomberg via Getty Images
34. AUS - Austin-Bergstrom
Travelers walk the main concourse at the Austin-Bergstrom International Airport in Austin, Texas, on Friday, Sept. 14, 2007. Jim Smith, who oversees the city-owned airport in Austin, Texas, needed help fast. Mexico's no-frills airline, VivaAeroBus, wanted to make Austin its first U.S. destination, and Smith had no free gate space. (Photo by Jack Plunkett/Bloomberg via Getty Images)
33. YYC - Calgary International
The Air Canada Airbus A319 jet that was forced to land and unload injured passengers at Calgary International Airport after encountering trouble and making an unscheduled landing on Thursday Jan. 10, 2008. The Rocky Mountains are visible in the background. At least 14 people aboard were injured when the Airbus A319 hit turbulence during a cross-country flight, an official said.(AP Photo/The Canadian Press, Larry MacDougal)
32. PHX - Phoenix Sky Harbor
The silhouettes of travelers are seen as a United Continental Holdings Inc. plane takes off from Phoenix Sky Harbor International Airport (PHX) in Phoenix, Arizona, U.S., on Friday, Sept. 6, 2013. Yields on benchmark securities climbed to almost two-year highs as consumers spent more on travel and tourism while manufacturing expanded modestly from early July through late August, according to the Federal Reserves Beige Book. Photographer: Patrick T. Fallon/Bloomberg via Getty Images
30. SEA - Seattle-Tacoma International
Passengers in the C Terminal at Seattle-Tacoma International Airport (SEA) head to their gates on June 2, 2013, in Seattle, Washington. Seattle, located in King County, is the largest city in the Pacific Northwest, and has become a hub for many European and Asian global business destinations. (Photo by George Rose/Getty Images)
29. YOW - Ottawa International
Travellers wait for baggage at Ottawa International Airport in Ottawa, Ontario, Canada, on Wednesday, Aug. 10, 2011. Canada's trade deficit widened more than forecast in June, signaling that the economy may have stalled or even contracted in the second quarter. Photographer: Brent Lewin/Bloomberg via Getty Images
28. MSP - Minneapolis-St. Paul International
Northwest Airlines jets wait at Minneapolis/St. Paul International Airport 30 May, 2006 in St.Paul, MN. AFP PHOTO/Karen BLEIER (Photo credit should read KAREN BLEIER/AFP/Getty Images)
27. SAN - San Diego International
A Southwest Airlines Co. airplane takes off at San Diego International Airport in San Diego, California, U.S. on Thursday, Sept. 19, 2013. Airlines must reconsider buying new or used aircraft as rising interest rates increase ownership costs, which could outweigh fuel savings at lower prices. Photographer: Sam Hodgson/Bloomberg via Getty Images
26. DTW - Detroit Metropolitan Wayne County
Vehicles sit at the curb outside the McNamara Terminal, serving Northwest Airlines among others, at Detroit Metropolitan Wayne County Airport in Detroit, Michigan, U.S., on Saturday, Feb. 23, 2008. Delta Air Lines Inc. and Northwest Airlines Corp. pilots are working to find a compromise over union seniority, a hurdle to the merger that would create the world's biggest carrier, people familiar with the talks said. (Photo by Fabrizio Costantini/Bloomberg via Getty Images)
25. ATL - Atlanta Hartsfield-Jackson
Delayed and stranded passengers waiting for flight information fill cubicles throughout Atlanta Hartsfield-Jackson International Airport after a snow storm on January 10, 2011 in Atlanta, Georgia. Atlanta Mayor Kasim Reed and Georgia Governor Sonny Perdue declared a state of emergency because of snowfall and ice across Atlanta and Georgia. A winter storm stretched across the Southeast as freezing rain and sleet followed on the heels of a heavy snow that blanketed the region. Airtran & Delta cancelled all flights out of Atlanta due to icy and snowy weather conditions. (Photo by Jessica McGowan/Getty Images)
24. DCA - Ronald Reagan Washington National
Holiday travelers line up on Thanksgiving eve for a security screening before boarding their flights on November 27, 2013, at Ronald Reagan National Airport in Washington, DC. AFP PHOTO/Paul J. Richards (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)
23. BOS - Boston Logan
The lines moved fast at TSA security checkpoints at Logan Airport's Terminal A. (Photo by John Tlumacki/The Boston Globe via Getty Images)
22. CLT - Charlotte Douglas International
A US Airways plane prepares for take-off at Charlotte-Douglas International Airport on January 16, 2009 in Charlotte, North Carolina. US Airways flight 1549 crashed into the Hudson River in New York City on January 15, 2009 shortly after take-off from LaGuardia Airport on its way to Charlotte, North Carolina. (Photo by Streeter Lecka/Getty Images)
21. DEN - Denver International
Security lines at Denver International Airport are long but moving fast, November 26, 2014. The airport was busy with thanksgiving travelers. (Photo by RJ Sangosti/The Denver Post via Getty Images)
20. SFO - San Francisco International
Passengers walk to the JetBlue Airways departure gate October 17, 2014 at the San Francisco International Airport in San Francisco, California. (Photo by Robert Nickelsberg/Getty Images)
18. BWI - Baltimore-Washington Thurgood Marshall
Travelers walk in front of arrival and departure screens at the Southwest Airlines ticket counter on Wednesday, November 23, 2005 at the Baltimore/Washington International Thurgood Marshall Airport in Baltimore, Maryland. (Photo by Chris Greenberg/Bloomberg via Getty Images)
17. YUL - Montreal Pierre-Elliot Trudeau
People gather to watch the Airbus A380 as it makes its first landing at the Pierre-Elliott Trudeau airport, 12 November, 2007 in Montreal, Quebec. Saudi Arabian billionaire Prince Walid Bin Talal on Monday ordered an Airbus A380, making him the first private buyer of the next generation super jumbo aircraft. AFP PHOTO/David BOILY (Photo credit should read DAVID BOILY/AFP/Getty Images)
15. MCI - Kansas City International
With no planes in sight, a lone passenger waits out the ice storm cancellations at Kansas City International Airport in Kansas City, Missouri, Tuesday, December 11, 2007. (Photo by Tammy Ljungblad/Kansas City Star/MCT via Getty Images)
14. IAH - George Bush Intercontinental
Lines of passengers wait at a security checkpoint 22 September 2005 before flying out of George Bush Intercontinental Airport in Houston, Texas, as people from south Texas evacuate in advance of Hurricane Rita. AFP PHOTO/Stan HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)
13. FLL - Ft. Lauderdale-Hollywood
Jason Cohen of New York City, catches a few last-minutes of sun before he was to catch a scheduled flight home to LaGuardia Airport in New York, Wednesday, February 2, 2011, at the Ft. Lauderdale-Hollywood International Airport. Almost 40 planes were parked at the airport Wednesday because of flight cancellations caused by the snow and ice storm in the Midwest and East Coast. Cohen said he was an 'optomistic,' traveler and thought he would get out today. (Joe Cavaretta/Sun Sentinel/MCT via Getty Images)
8. DFW - Dallas-Ft. Worth International
This 17 September, 2001, file photo shows an American Airlines jet taking off from Dallas/Ft. Worth International Airport in Dallas, Texas. American Airlines, the world's biggest carrier, announced 19 September, 2001, it was cutting least 20,000 jobs following the terrorist attacks against the US. No alternatives were being offered to fired employees because of the company's cash crunch after the 11 September attacks, in which two American Airlines jets were among the four lost, it added. 'This is, without a doubt, the most difficult thing I have had to do in my two decades at American,' chairman and chief executive Don Carty said in a letter to employees. AFP PHOTO/Paul BUCK (Photo credit should read PAUL BUCK/AFP/Getty Images)
7. YYZ - Toronto Pearson
Travellers scour the baggage claim at Toronto's Pearson airport for their luggage. Cold weather has caused a series of delayed or cancelled flights. January 7, 2014. (Randy Risling/Toronto Star via Getty Images)
1. LGA - New York LaGuardia
Travelers wait on line to check-in at the Central Terminal at LaGuardia Airport in the Queens borough of New York, U.S., on Tuesday, Dec. 28, 2010. Passengers stranded when airlines canceled more than 6,000 flights amid a snow storm in the eastern U.S. may wait days for another flight as carriers move aircraft and search for seats on crowded planes. Photographer: Jin Lee/Bloomberg via Getty Images
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"This morning as I write this letter, wait times up to 52 minutes were experienced between 6:00 am and 6:30 am," he added.
According to Southwell's letter, the TSA's Atlanta Airport team did manage to get a 7.5% staffing increase last year, but that proved to be "late and inadequate." This is because Hartsfield-Jackson, the world's business airport with more than 96 million passengers in 2014, saw traffic increase 10% over that same period.
Further, Southwell claims that traffic jumped another 14% in the first quarter of this fiscal year which has it "dreading the outcome of 2016."
With no sign of additional staffing on the way from the TSA, airport management has initiated programs to promote expedited security programs like TSA Pre-Check or Global Entry and the adoption of new technology in the screening process. However, Southwell doesn't believe this will be enough to alleviate the airport's checkpoint problems.
"Even with all of our efforts, however, as the airport's experience demonstrates, things appear to be only getting worse," Southwell added.
"We recognize that the issues raised in the letter are a concern, not just in Atlanta, which is fueled primarily by the rapid growth in travel volume combined with a renewed focus on our security mission," Mike England, a spokesman for the TSA wrote in an e-mail to Business Insider. "Resolving these issues and achieving our common goal calls for a collaborative approach with our industry partners. While we are working on better solutions, we believe the public will support our vital mission of ensuring safe air transportation."
We have reached out to Hartsfield-Jackson Atlanta International Airport for comment and will update this post when we hear back.