Runway Incursion at SFO

On May 26, 2007, a runway incursion occurred at San Francisco International Airport (SFO) when an Embraer EMB 120 Brasilia turboprop aircraft from SkyWest Airlines (flight SKW5741 operating as United Express), nearly collided with an Embraer 170 Regional Jet from Republic Airlines (flight 4912 operating as Frontier Airlines) at the intersection of runways 1L and 28R.

The SkyWest Embraer EMB 120 was cleared to land on Runway 28R at SFO, and the Republic Embraer 170 was cleared to take off from Runway 1L. The local controller heard an aural Airport Movement Area Safety System (AMASS) warning and called on SkyWest to hold. SkyWest stopped at the intersection of 1L and 28R and Republic lifted off and flew over it. The tower estimated that the airplanes missed each other by 300 feet, but the SkyWest crew said 30 to 40 feet while the Republic crew estimated 150 feet.

SFO ATCT is equipped with an Airport Movement Area Safety System (AMASS) that uses radar to track aircraft on and near the airport surface, providing conflict detection and aircraft location information to controllers. The system is able to detect conflicts between aircraft using the same runway, and, following a software modification that was installed on February 17, 2007, the system is also able to detect conflicts between aircraft using intersecting runways.

There were no reported injuries to occupants and no reported damage to either aircraft. However, at the time officials from the Federal Aviation Administration (FAA) described the runway incursion as the most serious incident of its kind in at least a decade, and the National Transportation Safety Board (NTSB) initiated an investigation into the incident.