(Adds detail on incident, FedEx comment, prior near miss under investigation)
By David Shepardson
Feb 4 (Reuters) - The Federal Aviation Administration and the U.S. National Transportation Safety Board are investigating an aborted landing in Austin, Texas, on Saturday morning by a FedEx cargo plane that had been set to land on a runway on which a Southwest Airlines jet was also cleared to depart from, the agencies said.
The two planes came close to colliding when the FedEx plane was forced to overfly the Southwest plane to avoid a crash, two sources briefed on the matter told Reuters.
"Shortly before the FedEx aircraft was due to land, the controller cleared Southwest Flight 708 to depart from the same runway," the Federal Aviation Administration (FAA) said.
The NTSB separately said it was investigating "a possible runway incursion and overflight involving airplanes from Southwest Airlines and FedEx."
The incident occurred in poor visibility conditions in Austin. The FAA said FedEx Express Flight 1432, a Boeing 767 cargo plane, which had departed from Memphis, was cleared to land on Runway 18-Left around 6:40 a.m. while the aircraft was several miles from the airport. The Southwest plane had not yet departed when the FedEx plane was nearing the runway.
"The pilot of the FedEx airplane discontinued the landing and initiated a climb out," the FAA said.
It was not clear precisely how close the two airplanes came to colliding, but flight tracking website data suggested they came very close.
The Cancun, Mexico-bound Southwest flight, a Boeing 737-700, safely departed and landed at 9:47 a.m. ET.
Southwest declined to comment. FedEx said its flight "safely landed after encountering an event," but declined further comment because of the ongoing investigations.
The NTSB and FAA are investigating another recent near-miss runway incident.
On Jan. 13, a Delta Air Lines plane came to a safe stop at New York's John F. Kennedy Airport after air traffic controllers noticed a Boeing 777 had crossed from an adjacent taxiway.
The FAA said the Delta Boeing 737 stopped its takeoff roll approximately 1,000 feet before reaching the point where American Airlines Flight 106 had crossed. (Reporting by David Shepardson; Editing by Sandra Maler and Leslie Adler)