--- title: Almost 1,000 Flights Grounded Because Of A Software Update description: The FAA reports that a software update was the likely cause of so many flights being grounded this weekend. canonical: https://time.com/4000563/software-update-flights-grounded/ author: TIME article:opinion: false article:content_tier: free article:published_time: 2015-08-17T17:51:38.000Z article:modified_time: 2026-05-11T04:44:30.608Z article:section: Business og:title: Here's Why Almost 1,000 Flights Were Grounded This Weekend og:description: FAA: Software update was the likely cause of so many flights being grounded. og:url: https://time.com/4000563/software-update-flights-grounded/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt5edc65c41f9d863b/69885f9f8e060115c6461e98/42-74499459.jpg?branch=production&width=1920&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: United Airlines outage og:type: article twitter:card: summary_large_image twitter:title: Here's Why Almost 1,000 Flights Were Grounded This Weekend twitter:description: FAA: Software update was the likely cause of so many flights being grounded. twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt5edc65c41f9d863b/69885f9f8e060115c6461e98/42-74499459.jpg?branch=production&width=1920&quality=75&auto=webp&crop=16:9 ---  # Why Almost 1,000 Flights Were Grounded This Weekend by [Michal Addady / Fortune](/author/fortune/) ## Michal Addady / Fortune Aug 17, 2015 5:51 PM CUT  08 Jul 2015, Chicago, Illinois, USA --- July 8, 2015 - Chicago, IL, USA - United Airlines passengers use the kiosk machines at the economy check-in area of O'Hare International Airport as flights were delayed due to a stoppage on Wednesday, July 8, 2015\. United grounded all U.S. flights because of ''automation issues.'' Planes at O'Hare were not leaving the gates, and some passengers said they were unable to book flights. (Credit Image: © Jose M. Osorio/TNS/ZUMA Wire) --- Image by © Jose M. Osorio/ZUMA Press/Corbis 08 Jul 2015, Chicago, Illinois, USA --- July 8, 2015 - Chicago, IL, USA - United Airlines passengers use the kiosk machines at the economy check-in area of O'Hare International Airport as flights were delayed due to a stoppage on Wednesday, July 8, 2015\. United grounded all U.S. flights because of ''automation issues.'' Planes at O'Hare were not leaving the gates, and some passengers said they were unable to book flights. (Credit Image: © Jose M. Osorio/TNS/ZUMA Wire) --- Image by © Jose M. Osorio/ZUMA Press/CorbisJose M. Osorio—© Jose M. Osorio/ZUMA Press/Corbis by [Michal Addady / Fortune](/author/fortune/) ## Michal Addady / Fortune Aug 17, 2015 5:51 PM CUT A software upgrade at an air traffic control center in Virginia went terribly wrong on Saturday, leading to 492 delayed flights and 476 cancelled flights, the U.S. Federal Aviation Administration told [_The Guardian_](http://www.theguardian.com/technology/2015/aug/17/air-traffic-control-software-upgrade-grounds-hundreds-of-flights-us-east-coast?CMP=twt%5Fa-technology%5Fb-gdntech "undefined"). Reagan National Airport was forced to cancel 50% of inbound flights and 42% of outbound flights; their delays averaged about 3 hours. Similarly, 58% of inbound flights and 36% of outbound flights were cancelled in Baltimore with average delays of over an hour. The upgrade was performed on the [En Route Automation Modernization](https://www.faa.gov/air%5Ftraffic/technology/eram/ "undefined") (ERAM) satellite-based computer system for air traffic management, a new computer system implemented by the FAA in March of this year. The administration posted a [statement on Facebook](https://www.facebook.com/FAA/posts/941598199215136 "undefined") saying that the update was meant to provide air traffic controllers with additional tools. They have assured consumers that they disabled the new features while they assess the issues. ### PHOTOS: Beautiful Long Exposures of Airplanes at Night  College Point Blvd., College Point, Queens, N.Y., June 2014. Kevin Kunstadt  36th Ave., Flushing, Queens, N.Y., June 2014. Kevin Kunstadt  Hermon MacNeil Park, College Point, Queens, N.Y., June 2014. Kevin Kunstadt  Greenpoint, Brooklyn, N.Y., June 2014. Kevin Kunstadt  East Williamsburg, Brooklyn, N.Y., June 2014. Kevin Kunstadt for TIME  Greenpoint, Brooklyn, N.Y., June 2014. Kevin Kunstadt for TIME  Greenpoint, Brooklyn, N.Y., June 2014. Kevin Kunstadt for TIME  Queens Botanical Garden, Flushing, Queens, N.Y., June 2014. Kevin Kunstadt  Flushing, N.Y., July 2014. Kevin Kunstadt  Ocean Blvd., Atlantic Beach, N.Y., July 2014. Kevin Kunstadt for TIME  Spray View Ave., Far Rockaway, N.Y., July 2014. 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