An Air Canada plane narrowly avoided what could have been the worst aviation disaster in history when it nearly landed on a crowded taxiway.

The Federal Aviation Administration (FAA) said Air Canada Flight 759 was given the all clear to land on San Francisco Airport's Runway 28R but the pilot inadvertently lined up for Taxiway C, which is parallel and where there were already four aircraft lined up.

After the air traffic controller sent the aircraft back around, it was able to land successfully on the correct runway.

"If it is true, what happened probably came close to the greatest aviation disaster in history," retired United Airlines Captain Ross Aimer, CEO of Aero Consulting Experts told the Mercury News.

"If you could imagine an Airbus colliding with four passenger aircraft wide bodies, full of fuel and passengers, then you can imagine how horrific this could have been," he added.

Audio of the incident reveals the pilot double-checking its landing site with the control tower. "Just want to confirm, this is Air Canada 759 we see some lights on the runway there. Confirming good to land?" the pilot asked.

"Air Canada 759 confirmed cleared to land runway 28 right," the control tower answered. "There is no one on 28-Right but you."

An unidentified voice can then be heard questioning the flight landing, CNN reported. "Where is this guy going? He's on the taxiway."

The air traffic controller told the plane to "go around" and try to land again. "Air Canada 759, it looks like you were lined up for Charlie there," the controller said, making a reference to Taxiway C.

A pilot from a United flight on the taxiway then radioed to air traffic control, according to CNN. "Air Canada flew directly over us."

An Air Canada spokesman said it is still investigating the incident. "Air Canada flight AC759 from Toronto was preparing to land at San Francisco airport Friday night when the aircraft initiated a go-around," Peter Fitzpatrick told CBC News. "The aircraft landed normally without incident. We are still investigating the circumstances and therefore have no additional information to offer."

Meanwhile, the airport spokesman said there would be no further comment.