The pilot of an Air Canada plane carrying 140 passengers made a last-minute maneuver to avoid landing on a San Francisco International Airport taxiway where four passenger jets were lined up to take off.

The Federal Aviation Administration said on Tuesday it is investigating why the pilot mistakenly lined up to land on the taxiway instead of the runway just to the left. An air traffic controller ordered the Airbus 320 to abort and circle for another landing, which it did without incident.

Aviation-safety consultant Todd Curtis called the incident "definitely a serious event since a landing on an active taxiway could lead to a catastrophic accident."

In audio posted on liveatc.net, which records flight communications, the pilot on the plane from Toronto and the air traffic controller sounded calm as the incident unfolded.

At first, the pilot said he sees "some lights on the runway," apparently alluding to planes on the taxiway, the aviation equivalent of feeder roads that planes use to roll between runways and terminals.

The controller assures the pilot there is no one on the runway. Seconds later, another voice - apparently one of the pilots on the taxiway - interjects "Where's this guy going? He's on the taxiway."

The controller orders the Air Canada jet to "go around," and the pilot acknowledges the command.

Roughly 30 seconds later, a United Airlines pilot on the taxiway says the jet "flew directly over us."

FAA spokesman Ian Gregor wouldn't comment on how close Air Canada Flight 759 from Toronto came to disaster, citing the ongoing investigation.

The incident, which Air Canada says it is investigating, was first reported on Monday by the Bay Area News Group.

It is rare for pilots to mistake a taxiway for a runway and when it happens it usually involves small planes at smaller airports. Taxiways do not have the same distinctive markings and lighting that appear on runways.

Source: Khaleej Times