There has been no comment yet from Air Canada officials, but the U-S Federal Aviation Administration is investigating a communication failure that almost led to a close call involving an Air Canada plane at San Francisco International Airport this week.
Investigators want to know why Air Canada Flight 781 did not hear instructions from air traffic control to abort a landing Sunday night.
ABC News has audio of controllers giving the instructions six times, but getting no response from the flight crew.
Pilots eventually told air traffic control they had radio problems, but not before the flight landed safely without ever acknowledging the instructions to go around.