A media report over the weekend suggested that a U.S. spy plane flying across Southern California last week may have played a part in last Wednesday's departure shutdown at Los Angeles International Airport and other terminals across the region.
Andrew Blankstein of NBC News reported ("Spy Plane Fries Air Traffic Control Computers, Shuts Down LAX"):
On Wednesday at about 2 p.m., according to sources, a U-2 spy plane, the same type of aircraft that flew high-altitude spy missions over Russia 50 years ago, passed through the airspace monitored by the L.A. Air Route Traffic Control Center in Palmdale, Calif. The L.A. Center handles landings and departures at the region’s major airports, including Los Angeles International (LAX), San Diego and Las Vegas.
The computers at the L.A. Center are programmed to keep commercial airliners and other aircraft from colliding with each other. The U-2 was flying at 60,000 feet, but the computers were attempting to keep it from colliding with planes that were actually miles beneath it.
Though the exact technical causes are not known, the spy plane’s altitude and route apparently overloaded a computer system called ERAM, which generates display data for air-traffic controllers. Back-up computer systems also failed.
As a result, the Federal Aviation Administration (FAA) had to stop accepting flights into airspace managed by the L.A. Center, issuing a nationwide ground stop that lasted for about an hour and affected thousands of passengers.
At this point, the FAA has said virtually nothing specific about the event beyond a reassurance that it's analyzing it and that engineers are working on a software fix to prevent a recurrence.
What we have a better handle on is the impact of the partial air traffic shutdown. According to the Los Angeles Times:
Throughout the day, 27 arriving flights were canceled, 212 were delayed and 27 were diverted to other airports, LAX says. And 23 departing flights were canceled, largely because of unavailable aircraft from canceled arrivals, and 216 were delayed.
LAX, John Wayne Airport in Orange County and Bob Hope Airport in Burbank were among the airports affected.