(AP) – A potential disaster was averted Friday when a Phoenix air traffic controller recognized two American Airlines jets mistakenly were flying the same flight number and acted quickly to avoid confusion and keep them a safe distance apart.

Audio of the incident shortly after midnight Friday shows how he found a solution to ensure the planes that were both called American 2482 maintained proper separation as one plane arrived from Chicago shortly after the other had taken off in Phoenix.

“I’ve been working air traffic for 25 years. I’ve never seen two aircraft pretty much merge with the same call sign. That’s pretty incredible,” the controller said after the departing plane had safely cleared the area.

If both pilots thought the controller was telling them to fly at the same altitude as they headed toward each other, they might have collided, so it was crucial they knew which plane he was directing.

Quick thinking ensured the controller’s instructions were clear

The audio posted by ATC.com shows how the controller quickly started referring to “American 2482 on the arrival” and “American 2482 on the departure” to keep the two planes straight.

The controller kept the arriving plane safely above the departing plane even as their flight paths converged and made sure that the pilots of both airlines saw each other when they were still miles apart. He also directed the departing plane not to climb too high, so a gap would remain between the planes.

The arriving pilot complimented the controller for his “nice work” once the two planes had passed each other safely.

“It could have been disastrous, but I’m glad it worked out,” the controller replied.

Expert says airline must have missed that the flights would overlap

Aviation safety expert Steve Arroyo said it’s likely that someone inside the airline’s dispatch center failed to catch that both planes would be in the air at the same time with identical flight numbers when both the dispatcher and the pilots signed off on the flight plan.

“You can drop the ball and that shouldn’t happen, but it’s nice to see that the system is resilient and we have all the safeguards,” said Arroyo, who has only seen this type of issue a couple times in his four decades with United Airlines. Arroyo started his career as a dispatcher before becoming a pilot.

Flight 2482 is a round-trip route that often flies back and forth between Chicago and Phoenix. Typically the same plane goes back and forth, but the flight out of Chicago was delayed by weather, so American found a second plane in Phoenix and that flight left on time. The result was that both planes briefly shared the same airspace before the arriving flight landed.

The government and airline will determine how this occurred

The Federal Aviation Administration and American Airlines will investigate how this happened, and they both emphasized how glad they were that everyone remained safe.

“The diligence and professionalism of air traffic controllers and our pilots ensured required separation was always maintained and the issue was identified and addressed. Both flights continued safely and without incident,” American Airlines said in a statement.