Audio has emerged of the moment an Air Canada aircraft nearly landed on four other planes, narrowly avoiding what could have been the “greatest aviation disaster in history.”

The A320 from Toronto was cleared to land on a runway at San Francisco International Airport in the US just before midnight on Friday local time.

But instead, the pilot of Flight AC759 inadvertently lined up to land on a parallel taxiway where four planes — loaded with passengers and fuel — were waiting to depart.

“What happened probably came close to the greatest aviation disaster in history,” retired United Airlines Captain Ross Aimer, CEO of Aero Consulting Experts, told 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.”

Audio from the air traffic controller communication — archived by a user on LiveATC.net — recorded the confused Air Canada pilot asking if he was clear to land on 28R because he saw plane lights on the runway.

“There’s no one on 28R but you,” the air controller responded.

An unidentified voice asked: “Where’s this guy going? He’s on the taxiway.”

The air controller then quickly told the Air Canada pilot to go around, adding: “It looks like you were lined up for Charlie (Taxiway C) there.”

A United Airlines pilot radioed in: “United One, Air Canada flew directly over us.”

The control tower responded: “Yeah, I saw that, guys.”

Captain Aimer said the near-miss sparked considerable discussion in aviation circles.

“This is pretty huge. My buddies called and asked if I knew about it,” the former pilot told Mercury News. “They’re a sitting duck on the taxiway. They can’t go anywhere.”

Wide body planes can carry between 200 and 480 passengers, plus crew.

The US Federal Aviation Administration is now investigating the distance between the Air Canada aircraft and the jets that were lined up on the taxiway.

Air Canada is investigating the circumstances and has no additional information to offer, it said in a statement. Details on the pilot’s fitness to fly, or whether he has been reprimanded, have not been released.