Two United and Alaska Airlines pilots were forced to abort their landings after nearly colliding with a Southwest jet.
Air traffic controllers at San Francisco International Airport berated a Southwest pilot after they were heard saying "they shouldn't be on the runway" during the terrifying incident on May 19.
The Federal Aviation Administration confirmed yesterday the plane a Southwest Jet had crossed Runway 28 left and entered Runway 28 right causing an Alaska Airlines pilot to abort his landing and circle round.
The incident also saw a United Airlines flight abandoned their landing after the Southwest jet was caught taxiing in the middle of both runways.
In a statement, the Federal Aviation Administration tried to play down the incident, it said: "The FAA looked into the events and determined the appropriate steps were taken to ensure safe operations."
The National Transportation Safety Board confirmed it is not investigating the incident.
However, Ross Sagun, who flew for more than 40 years as a commercial airline pilot, said the incident was a “runway incursion” and a “very serious event".
He told San Francisco Chronicle: “It’s definitely reportable and I hope it’s being investigated. If not, it should be.”
A United spokesperson praised the decision by the company’s pilot to abort the landing.
It said: “We commend our pilots for their quick thinking and good work during their response to this incident.”
The shocking incident comes just months after a FedEx plane flew around 100ft above the top of a Southwest jet in Austin, Texas, after an air traffic controller cleared both planes to use the same runway.
Shortly after the incident, a crew of an Alaska Airlines plane saw the same Southwest jet crossing a second runway - forcing the pilots to abandoned their landing.
The United and Alaska planes had to circle around until it was safe to land.
Despite recent criticism towards the FAA, the nation's air-traffic system is safe, according to its interim boss.
Acting FAA administrator Billy Nolen defended the safety of airline travel in the United States after recent incidents at John F. Kennedy Airport in New York, in Austin, Texas, and off the coast of Hawaii.
Still, Nolen said, he is putting together a team of experts to review airline safety.
“We are experiencing the safest period in aviation history, but we do not take that for granted,” Mr Nolen said during testimony before the Senate Commerce Committee. “Recent events remind us that we cannot become complacent.”
Mr Nolen pointed out that the US has not had a fatal crash involving an airline plane since 2009.
However, he is forming an expert panel to review the aviation system and hold a safety summit next month to determine what steps are needed to maintain the record of recent years.