US aviation authorities are investigating a near miss at a San Francisco airport after an Air Canada plane almost landed on a crowded taxiway rather than the runway.

The Air Canada Airbus 320 was cleared to land at a runway at San Francisco international airport late on Friday. The pilot, however, inadvertently began descending toward one of the taxiways, where four airplanes laden with passengers and fuel sat waiting for permission to take off, according to the US Federal Aviation Administration.

Audio of the conversations between air traffic control and pilots, posted on the Live ATC website, captured the confusion. The Air Canada pilot can be heard asking if he’s clear to land, given that he can see other lights on the runway. He’s told there are no other planes on the runway.

Another voice chimes in, sounding the alarm over Air Canada’s trajectory: “Where’s this guy going? He’s on the taxiway.”

The pilot was immediately instructed to pull up, circle around and approach the landing again. “It looks like you were lined up for Charlie [Taxiway C] there,” the air traffic controller told the pilot. The taxiway sits parallel to the runway.

A United Airlines pilot then weighed in: “United One, Air Canada just flew directly over us.” The air controller responded: “Yeah, I saw that, guys.”

About 15 minutes later, the Air Canada flight landed safely. “The plane made another approach and landed without incident,” the Federal Aviation Administration said in a statement.

The FAA, which described the incident as “very rare”, is now investigating how close the Air Canada plane came to the four other jets sitting on the taxiway at the time.

The San Jose Mercury News, which was among the first to report the story, said the near miss was being widely discussed among aviation circles.

“If it is true, what happened probably came close to the greatest aviation disaster in history,” retired United Airlines captain Ross Aimer told the newspaper. “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.”

Air Canada also said it was investigating the reports. Five crew and 135 passengers were onboard the flight from Toronto when the aircraft was directed to make another approach, a spokesperson said in an email. “The aircraft landed normally without incident. We are still investigating the circumstances and therefore have no additional information to offer.”