Story updated on 11 July to include comment from Air Canada in paragraph six.
An Air Canada Airbus A320 came close to landing on a busy taxiway at San Francisco International airport the evening of 7 July, the Federal Aviation Administration confirms.
The FAA says four other aircraft were on the taxiway at the time of the incident, though it declines to specify how close the Air Canada A320 came to those aircraft.
Controllers had cleared pilots Air Canada flight 759 from Toronto to land on San Francisco's runway 28R.
The A320 pilots, however, "inadvertently" lined up to land on taxiway C, which runs parallel to the runway, says the FAA.
Controllers ordered the A320's pilots to go around, and the aircraft later landed safety.
Air Canada tells FlightGlobal the aircraft performed a go-around and that it carried 135 passengers and five crew. "We are still investigating the circumstances and therefore have no additional information to offer", the airline adds.
Audio recordings of the incident reveal confusion among the Air Canada pilots about lights on the runway and suggest the A320 came close to at least one aircraft on the taxiway.
"Tower, just want to confirm… We see some lights on the runway," one Air Canada pilot tells controllers, according to a recording available at LiveATC.net.
"Confirmed. Cleared to land Runway 28R. There is no one on 28R but you," the controller responds.
A moment later, a pilot from another aircraft breaks in.
"Where's this guy going? He's on the taxiway," that pilot says.
Immediately, the controller orders Air Canada flight 759 to go around.
Next, a pilot from United Airlines flight 1, a Boeing 787 service to Singapore, tells controllers, "Air Canada flew directly over us."
"The FAA is investigating the distance between the Air Canada aircraft and the jets that were lined up on taxiway C," the agency says.