Air Canada near-miss might have triggered 'greatest aviation disaster in history' (VIDEO)

In what one aviation expert called a near-miss of what could have been the largest aviation disaster ever, an Air Canada pilot narrowly avoided a tragic mistake: landing on the San Francisco International Airport taxiway instead of the appropriate runway.

Sitting on Taxiway C shortly before midnight  on July 7 were four fully-loaded airplanes full of passengers and gas awaiting permission to take off, according to the Federal Aviation Administration, which is investigating the "rare" incident, the Mercury News reported.

An air traffic controller sent the Air Canada Airbus 320 on a "go-around" - an unusual event where pilots must pull-up and circle around to try again - before landing safely, according to the federal agency.

FAA investigators are still trying to determine how close the Air Canada aircraft came to landing and potentially crashing into the four aircraft below, but the apparent pilot error already has the aviation industry buzzing.

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