FedEx and Southwest planes that nearly collided were 'less than 100 feet' from collision, investigators say

The FedEx and Southwest Airlines flights that nearly collided at an Austin airport over the weekend came within 100 feet of colliding into each other, federal investigators say.

The incident at Austin-Bergstrom International Airport Saturday involved a Boeing 737 operated by Southwest Airlines that was scheduled to depart the airport and a Boeing 767 cargo plane operated by FedEx that was cleared to land. The FedEx plane was attempting to land on the same runway the Southwest Airlines flight was scheduled to depart from before the FedEx flight aborted its landing.

"Shortly before the FedEx aircraft was due to land, the controller cleared Southwest Flight 708 to depart from the same runway," the FAA said Sunday in its preliminary investigation. "The pilot of the FedEx airplane discontinued the landing and initiated a climb out."

FedEx, Southwest and 'potential catastrophe'

Jennifer Homendy, chairwoman of the National Transportation Safety Board, told CNN the two planes came as close as 100 feet from each other.

"It was very close, and we believe less than 100 feet," Homendy said.

She added she was proud of the the FedEx flight crew and pilot for avoiding the collision, while also telling Reuters the Southwest Airlines pilots would not have known what was going on. She said there was poor visibility at the time of the incident.

“They saved, in my view, 128 people from a potential catastrophe," Homendy said.

The NTSB told USA TODAY it will release its preliminary report on the incident within the next two weeks.

Fire in the plane cabin: Four people taken to hospital after a laptop 'ignited' during a flight

United Airlines: FAA proposes fining airline $1.15 million for allegedly removing fire safety check

What happened at the Austin airport?

Available live audio from Austin's air traffic control system at the time of the incident indicates both pilots were made aware of the other's presence.

Upon giving the Southwest flight the go-ahead to take off, the air traffic controller told the plane that the FedEx cargo plane was three miles away. The Southwest pilot responded and acknowledged the traffic, as the FedEx pilot was notified by controllers about the Southwest flight's departure.

About 20 seconds after the Southwest pilot informed controllers the plane was "rolling," controllers told the pilot, "Southwest abort. FedEx is on the go."

Nearly nine seconds later, the tower tells the Southwest flight to turn right when able. Southwest immediately responds by saying, “Negative.” The tower comes back about 17 seconds later and tells the FedEx pilot to climb and maintain 3,000 feet and turn left, which the pilot confirms upon receiving the instruction.

Near the end of the recording, after the FedEx plane has landed and said it cleared the runway, the tower apologizes to the pilot and thanks them for their professionalism.

FedEx previously told USA TODAY that its cargo plane arriving from Memphis landed safely at the airport, and the Southwest Airlines flight arrived to its destination in Cancun, Mexico early, according to FlightAware data.

Contributing: Skylar Seipp, Austin American-Statesman

Follow Jordan Mendoza on Twitter: @jordan_mendoza5.

This article originally appeared on USA TODAY: NTSB: FedEx, Southwest planes were 'less than 100 feet' from collision