The near collision - at least the third such incident in the state since February to prompt federal investigations
- occurred Monday at Bob Hope Airport in Burbank, but was not disclosed by the National Transportation Safety Board until Friday.
It was not immediately clear why the incident was not reported earlier. A call to the NTSB was not returned Friday.
The Boeing 737-700 carrying 119 passengers and five crew members was landing from Oakland when a Cessna 172, which was involved in a practice maneuver known as "touch and go" on another runway, arrived at the intersection at about the same time.
The planes came within an estimated 200 feet vertically and 10 feet laterally of each other, the Federal Aviation Administration said.
During a "touch and go" practice, a plane briefly lands on a runway before accelerating and becoming airborne again. The practice doesn't normally present a potential for conflict, but the air traffic controller misjudged the spacing of the two aircraft, FAA spokesman Ian Gregor said.
"The controller instructed the Cessna pilot to turn at a point that had the two aircraft arriving at the intersection at roughly the same time," Gregor said. "The controller failed to recognize the potential conflict and did not instruct the Cessna to go around."
The controller has been fully certified at the Burbank tower for about two years.
"He is an excellent controller who made an unusual, and unfortunate, mistake," Gregor said, adding that all of the Burbank controllers received training on what went wrong and why, and how to prevent a recurrence.
A call to a Southwest Airlines spokeswoman was not immediately returned Friday.
The Cessna was registered to John Rhodes and Brenda Thomas of Northridge, a suburb northwest of Los Angeles. A call to their residence was not immediately returned.
