Better in their words…

Just an interesting story. Another on the U-2 I will also post.
==============
An air-traffic control outage last week across parts of four Western states stemmed from a software glitch sparked by the flight of a single, high-altitude U-2 Pentagon reconnaissance plane in the region, according to two people familiar with the details.

Preliminary information indicates that the problem—affecting roughly 500 flights in and out of Los Angeles International Airport alone—resulted from the temporary shutdown of a key element of the Federal Aviation Administration’s ongoing, $40 billion traffic-control modernization effort, these people said.

The chain of events started with a flight plan that resulted in an improper computer code for the U-2’s flight, according to one person, apparently prompting malfunctions that overwhelmed the computer system.

The system ultimately went into overload and shut itself down as a precautionary measure. The FAA implemented a fix quickly after the incident, but on Sunday an FAA spokeswoman didn’t have any comment about the specific cause.

Last Wednesday’s incident illustrates the vulnerability of the core portion of the modernized traffic-control network, a component dubbed ERAM, or En Route Automation Modernization, which already has faced a variety of budget and performance setbacks. Both primary and backup ERAM computer systems were affected. The role of the U-2, a 1950’s-vintage spy plane able to fly as high as 70,000 feet, was reported earlier by NBC News.

The temporary ERAM shutdown at an FAA facility in Palmdale, Calif., disrupted travel plans for tens of thousands of travelers, at its height prompting a nationwide halt to takeoffs of all flights headed to the region.

It took several hours to sort out the problem and resume normal air traffic to and from the busy hub at Los Angeles, as well as fields throughout southern and central California, southern Nevada, southwest Utah and western Arizona.

At the time, FAA officials didn’t elaborate on the technical problems associated with the delays except to say that for about an hour the Palmdale center couldn’t accept flights traversing its coverage area.

Considered the backbone of the nationwide traffic-control upgrade, ERAM replaces a 1970s-era hardware and software system written in now-obsolete programming language and used at many of the 20 “en route” control centers that generally handle air traffic at altitudes over 10,000 feet.

ERAM began in 2002 as a $2.1 billion contract awarded to Lockheed Martin Corp. But it already is three years late—the FAA now expects it to be installed in all the centers by late this year—and the cost has ballooned by $330 million.

Congressional investigators have criticized the FAA for seemingly focusing only on getting ERAM operational with its “core functionality,” while leaving important and complex safety and capacity “enhancements” for later.

Those enhancements include a flight plan “trajectory modeler” designed to project aircraft flight paths, help planes avoid colliding and help controllers ensure accurate handoffs when planes move from one section of airspace to the next. Another enhancement is a “fusion” function that allows for the integration of multiple radars and satellite-based information for controllers. ERAM also will require adjustments once the FAA activates the bulk of its so-called for NextGen initiative, a satellite-based navigation and traffic-control network eventually intended to give pilots greater responsibility for determining routes and maintaining safe distances from nearby traffic.

Nevertheless, ERAM is seen as a big improvement by those air-traffic controllers who now use it. It has fully redundant backups, so it shouldn’t lose functions when the main system conks out or needs maintenance. The system can process data from more ground-based radars. It offers a tool called “conflict probe,” which looks ahead 20 minutes in time and calculates—based on two planes’ altitude, speed and direction—if they are going to get too close. But that function is less sophisticated than the “trajectory modeler,” which does the same thing more broadly and has had mixed results on rollout.

The ERAM system hasn’t suffered exactly this type of malfunction before, according to people familiar with its history. As part of their investigation, FAA officials are expected, among other things, to examine if the level of traffic contributed to exceeding system’s computing capacity.

The Air Force currently operates a fleet of more than 30 U-2S models, all delivered in the 1980s, which can take up to one hour to reach maximum cruising altitude. When flying over U.S. airspace, crews typically file flight plans with the FAA to ensure the spy planes maintain safe separation from each other and all other aircraft.

Write to Andy Pasztor at andy.pasztor@wsj.com and Susan Carey at susan.carey@wsj.com

U-2 Spy Plane Triggered Air-Traffic Outage – WSJ.com.