Washington (CNN) -- An air traffic controller unintentionally placed a passenger jet and a small propeller plane on a collision course at a Mississippi airport last summer, causing the planes to pass within 300 feet of each other in midair, according to the National Transportation Safety Board.
Though neither plane had to swerve, the pilot of the passenger jet commented, "Wow, That was close," and the controller's supervisor later told investigators it was a "miracle" no one died.
The NTSB report, while placing blame squarely on the controller's shoulders, also raises questions about the overall management of the Gulfport-Biloxi Airport control tower.
The controller, Robert Beck, a 23-year veteran of the Federal Aviation Administration, had been allowed to work as "controller in charge" and as an on-the-job training instructor for other controllers before the incident, the NTSB said. He was suspended and decertified after the June incident, but has since been retrained, recertified, and is back on the job at the Mississippi airport.
CNN was unable to reach Beck by telephone Wednesday for comment.
The agency also made "management changes" at the tower after the incident, the FAA said without elaborating.
"The FAA is committed to running the safest air transportation system in the world," spokeswoman Brie Sachse said in a statement.
The National Air Traffic Controllers Association said it is taking the NTSB report seriously.
"We welcome the examination of this incident by federal officials and plan to work with the FAA to continue to improve the safety of our aviation system," said NATCA spokesman Doug Church.
The incident happened last June, at a time when the FAA was still reeling from media reports of air traffic controllers sleeping and being inattentive.
According to the NTSB, Beck cleared a Cessna 172 for takeoff on one runway, and 16 seconds later cleared the passenger jet for takeoff on another, setting them on intersecting flight paths.
As the Cessna lifted off and climbed to 300 feet, the jet passed directly in front of it at the same altitude. The planes passed within 300 feet of each other, the NTSB said.
The first officer, who was at the controls of the jet, did not see the plane, but his captain commented, "Wow, That was close!" he told investigators.
The passenger jet, ExpressJet flight 2555, carried 50 passengers and a crew of three. The Cessna had two on board, a student pilot and an instructor.
In a "factual report" by an NTSB investigator, the air traffic controller's supervisor said that, in his opinion, "the incident occurred because (the controller) was not paying attention."
Beck told investigators he cleared both planes to take off, but anticipated the Cessna would take three to five minutes to get airborne, the report says. He "considered it inconceivable that the Cessna departing runway 18 could have conflicted with the (Embraer 145 jet) off of runway 14," the report says.
The controller did not see the near collision, but found out the next day the incident was being investigated, the NTSB said.
The incident also gives fodder to critics of FAA management.
Before the incident, the report says, Beck was not authorized to conduct on-the-job training, but "had not been advised and was not aware" of the restriction. After the incident, he was restricted from working as a local controller, although no one told him, the report says.