NTSB say Air Canada flight at SFO came just feet from taxiway

SAN FRANCISCO (KGO) -- A newly released National Transportation and Safety Bureau report and photos show just how close an Air Canada flight was to the taxiway at San Francisco International Airport last month.

"This was a disaster averted," said retired pilot Chris Zwingle. The NTSB now says the Air Canada plane was just 59-feet from the ground.

RELATED: Air Canada flight nearly lands on taxiway at San Francisco International Airport

"The fact that the United 787 that was number one on the taxiway had a tail height of approximately 56 feet, well it's alarming the difference between 59 and 56 but I think those aircraft were separated laterally by a significant amount," Zwingle explained.

The AirCanada pilot questioned lights he saw on what he believed was the runway.

"It's a very rare occurrence for pilots to actually lock onto a taxiway at night versus the runway because taxiway lights are blue and runway lights are white," said ABC News Aviation Analyst John Nance.

According to the report, the AirCanda flight was so off course that it hit a blind spot in the airport's radar system for 12 seconds. The radar system should have alerted air traffic controllers the aircraft was not where it was supposed to be.

RELATED: NTSB investigating after Air Canada flight nearly lands on taxiway at SFO

A United Airlines Pilot radioed the control tower to let them know Air Canada was descending on the taxiway. The Air Canada pilot had already begun to pull up when air traffic control ordered a go-around.

"As close as it was and as potentially scary as it was the whole thing worked so message to passengers the system is safe," said Zwingle.

The NTSB had not yet reached a final conclusion in its investigation.