Air disaster narrowly avoided after Air Canada pilot almost ploughs into four planes during San Francisco landing

A major air disaster has been narrowly avoided after a plane with 140 passengers onboard almost landed on a taxiway where four passenger jets were lined up to take off.

Officials are investigating why the Air Canada pilot mistakenly made his approach toward the taxiway at San Francisco International Airport instead of the runway just to the left.

The near catastrophe was prevented when an air traffic controller ordered the Airbus 320 to abort and circle for another landing on Friday night.

In audio posted on liveatc.net, which records flight communications, the pilot on the plane from Toronto and the air traffic controller sounded calm as the close call unfolded.

At first, the pilot said he sees "some lights on the runway", apparently referring to planes on the taxiway.

The controller assures the pilot there is no one on the runway. Seconds later, another voice - apparently one of the pilots on the taxiway - interjects, "Where's this guy going? He's on the taxiway."

The controller orders the Air Canada jet to "go around", and the pilot acknowledges the command.

Roughly 30 seconds later, a United Airlines pilot on the taxiway says the jet "flew directly over us".

Federal Aviation Administration spokesman Ian Gregor would not comment on how close Air Canada Flight 759 came to disaster, citing his agency's ongoing investigation.

The National Transportation Safety Board is also reviewing what happened.

Investigators will be able to determine the Air Canada plane's altitude and exact location using the flight-data recorder.