How the U2 spyplane caused commercial flight disruption:
“”"The incident, which occurred shortly after 3 pm Pacific on April 30, caused the cancellation of around 50 flights outbound and inbound to LAX as well as delaying a further 455 flights around the country. The FAA says the ERAM “experienced problems while processing a flight plan filed for a U-2 aircraft that operates at very high altitudes under visual flight rules (VFR). The computer system interpreted the flight as a more typical low altitude operation, and began processing it for a route below 10,000 feet.”
The issue is believed to have been exacerbated by a large number of waypoints in the flight plan for the U-2S which was on a regular training flight and passing through airspace controlled by Los Angeles Air Route Control Center in Palmdale, Calif, at around 60,000-ft. However sources also indicate that an error in a new software load in the control center misinterpreted the location of the U-2S flying VFR at that altitude. “The extensive number of routings that would have been required to deconflict the aircraft with lower-altitude flights used a large amount of available memory and interrupted the computer’s other flight-processing functions,” says the agency."""
http://aviationweek.com/equipment-technology/faa-boosts-eram-processing-after-u-2-triggers-la-shutdown