In July of 2017, an Air Canada passenger jet loaded with 135 passengers and 5 crewmembers nearly landed on a taxiway at San Francisco International Airport, where four jets were waiting to take off.

At the last moment, the pilot aborted the landing, averting what could have been the worst aviation accident in history. How was this possible in this day of automation and super-accurate GPS navigation? Join Miles and Lars Perkins to find out.