As it approached San Francisco International Airport to land on July 7, Air Canada Flight 759 mistakenly lined up with a taxiway where four planes were waiting, instead of a runway. The captain of the Airbus A320 aborted the landing. Air Canada did not immediately respond to a CNN request for comment.
The incident represents one of the most serious in recent memory and could have caused one of the worst air disasters in aviation history, according to air safety experts.
As Flight 759 passed over the first airliner, a United Airlines Boeing 787, the Air Canada crew aborted its landing. The crew commanded full power from the engines. At that point, it was just 85 feet above the ground.
Two and a half seconds later, the A320 dipped as low as 59 feet before climbing, according to NTSB data. For comparison, the height of the tail of a 787 is just shy of 56 feet.
The second airliner on the taxiway -- a Philippine Airlines Airbus 340 -- had switched on its landing lights, apparently to make itself visible to the inbound jet, the NTSB said.
Two other aircraft, another United Boeing 787 and a 737-900ER were also on the taxiway as the Air Canada jet climbed away.
The pilots on the Air Canada jet told NTSB investigators they thought they were lined up for runway 28R as they came in to land around midnight PDT. Parallel runway 28L was closed for construction and was unlit except for a 20-foot illuminated 'X' on it. The Air Canada flight was instead headed for taxiway C, parallel to 28R.
The pilots said they didn't recall seeing any other planes, but they broke off the landing "but that something did not look right to them," according to the NTSB.
The taxiing United 787 called the control tower just before the Air Canada jet aborted its landing, asking, "where's this guy going?"
A few seconds after they started the process to climb, an air traffic controller told the Air Canada flight to go around.
According to the safety board, a system designed to monitor ground traffic at San Francisco lost the approaching A320 for about 12 seconds, only reappearing as it passed over the first airplane.
The NTSB said the Air Canada captain has more than 20,000 flight hours and almost 4,800 as a captain of an Airbus A320. The first officer has 10,000 flight hours.
The Air Canada's cockpit voice recorder was overwritten, the NTSB said.
The NTSB is still investigating the incident and said this update contains no conclusions for what caused the near-miss.
Such incidents are incredibly rare, but can end in disaster. Runways and taxiways have specifically demarcated lighting to provide visual cues to pilots to avoid such incidents, but dangerous mix-ups do happen.
In 2009, a Delta Air Lines flight landed on a taxiway in Atlanta's Hartsfield-Jackson International Airport, and in 2015 an Alaska Airlines jet landed on one at Seattle-Tacoma International Airport. No one was hurt in either incident.
Runway incidents at takeoff and landing still account for the largest portion of aviation accidents.
Nearly 47% of fatalities occur during final approach and landing, according to an analysis of accidents from 2006 to 2015 by Boeing. The newest generation of aircraft now include moving airport maps on their displays to alert the pilot of the aircraft's position relative to a runway or a taxiway.
Companies like Honeywell Aerospace have also developed systems to advise pilots on the ground and in the air if they're approaching a taxiway or a runway, but such equipment is an optional feature on many aircraft.