A glitch in an air traffic control computer last week that brought airline flights to a standstill across the region was blamed on the system's inability to process the flight plan of a high-flying U-2 spy plane, the Federal Aviation Administration announced Monday.
Officials said that U-2s, a Cold War-era reconnaissance aircraft, usually operate at very high altitudes under visual flight rules. But an FAA computer at a Palmdale air traffic control center interpreted the flight as a low-altitude operation and began processing it for a course below 10,000 feet.
The large number of aircraft reroutings that would have been required to prevent conflicts heavily taxed the computer's memory and disrupted the system's processing of other flights, according to the FAA.
FAA officials said they resolved the problem in about an hour and then adjusted the system to require specific altitude information for each flight plan and to increase the amount of computer memory available to process flight plans.
The FAA issued a nationwide ground stop for planes heading into the airspace managed by the Palmdale center, disrupting travel in many cities. At LAX, officials reported 27 flight cancellations, 212 delays and 27 diversions in connection with the problem.