A new audio recording captures the moment an Air Canada flight from Toronto narrowly avoided colliding with four other passenger aircraft at San Francisco International Airport. The incident, which ultimately ended with the plane correcting course and landing safely, has shocked the aviation world.

“If it is true, what happened probably came close to the greatest aviation disaster in history,” retired United Airlines Capt. Ross Aimer, CEO of Aero Consulting Experts, told Mercury News in a story published Monday. “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.”

At 11.56 p.m. Pacific time on Friday, an Airbus 320 operated by Air Canada as flight AC759 was cleared to land at runway 28R, but instead the plane lined up with taxiway C that runs parallel to the runway. Air traffic control at the airport told the plane to fly around, and after it completed the maneuver it landed without incident. Had the plane landed on the taxiway, it could have collided with four jets waiting to take off.

The Federal Aviation Administration is now conducting a probe to find out how close the flight came to the ground.

Listen to the recording here:

At 0.15 the Air Canada pilot asks if he’s clear for landing as he “can see some lights on the runway there.” Air traffic control responds at 0.35 confirming that there’s “no one on 28-right but you.”

“Where’s this guy going?” another voice interjects. “He’s on the taxiway!”

“Air Canada, go around,” the traffic control responds.

Soon after, at 0.46, a United pilot states that “Air Canada flew directly over us” on the taxiway.

The plane eventually landed 50 minutes late, at 12.11 a.m. Although the plane missed its scheduled arrival time, the teams involved managed to avoid what could have been a disastrous incident.

Photos via Getty Images / David McNew