A commercial jet loaded with passengers taking off from San Francisco, headed to China, and a small Cessna came so close that both planes had to take evasive action.
The National Transportation Safety Board and the Federal Aviation Administration are investigating this near-miss. Even though everyone on both planes is fine, experts agree this should have never happened.
United Airlines flight 889, headed for Beijing, had been cleared for takeoff from runway 28L at approximately 11:15 a.m. This happened even though a Cessna 182, which is a small private plane, was approaching in the same air space. As the 777 flew west and was at about 1,000 feet, the pilot actually saw the Cessna heading right for him. An on-board alert sounded, telling the United pilot to adjust vertical speed and descend immediately. As he did that, the Cessna made a mid-air turn and flew right over the United plane.
The United pilot said he could actually see the underbelly of the smaller plane, that is how close the two were -- only 300 feet apart vertically and 1,500 feet horizontally. Federal guidelines require planes to be much farther apart -- a minimum of 500 feet vertically and 1.5 miles horizontally.
"Airplanes operate in very close proximity to one another every single day at every major airport in the country. It's tightly controlled airspace. It's a carefully choreographed operation," said FAA spokesman Ian Gregor. "I know it is surprising to some people to know how closely airplanes operate, but we maintain a safety bubble around each aircraft."
The FAA agrees though that the planes were too close together and that the air traffic controller in the tower should have noticed this earlier.
ABC7 aviation consultant Ron Wilson calls what happened Saturday a very big deal and something that could have ended disastrously.
"If the two of them went down in that area just beyond the west end of the airport property, you could end up in the middle of a residential neighborhood or in the middle of a commercial district which encompasses that area and you could've had... I just don't like to think about that," said Wilson.
The FAA says no action will be taken against the air traffic controller on duty that day, but there will be re-training and re-education of staff.