aviation consultant mike mccarron shows us the track approaching sfo yesterday morning. the faa said the pilot was cleared to the land on 21r, but controllers noticed it was headed for 21l where a virgin american airliner was set to take off for hawaii. >> you're looking maybe 20 seconds -- 15, 20 seconds to cover a mile's distance. it was close but there was more than enough time. >> the air mexico pilot did pull up, circle around and land safely. this follows two similar incidents in the past nine months involving air canada planes. in one incident, an air canada jet nearly landed on top of one jet awaiting takeoff. passenger's shared their thoughts. >> we had to go up and back around because the planes were too close. >> i'm confident. >> it's a near miss. >> they say they can take comfort in the fact that the system works. >> the controllers watched, saw he wasn't lined up properly, gave the command to go around, he went around and landed safely. >> reporter: the faa is, of course, investigating this incident. the question is how did that pilot, who was clear for one