Air traffic in the USA, which was severely disrupted by a system failure, slowly resumed after a few hours on Wednesday.

The US Federal Aviation Administration (FAA) had halted domestic flights due to the disruption, but allowed them to resume at 2.30 pm (CET). The closure has been lifted and troubleshooting is still ongoing, the FAA explained. The Notam (Notice to Air Missions) system, which is important for pilots to prepare for flights, failed at around 2.00 a.m. (local time on the East Coast). President Joe Biden was informed and instructed the Department of Transportation to investigate. Whether the cause was a hacker attack is currently unclear, said Biden. There were no indications of this, the White House had previously tweeted. Flights between Germany and the USA were not affected.

The security system informs pilots about scheduled restrictions and short-term dangers on the route or changes in technical procedures at airports. For example, they find out whether there are airspace closures following volcanic eruptions or due to military conflicts, as is currently the case in Europe due to the war in Ukraine. Cockpit staff check the sometimes hundreds of pages of information before take-off. Overloaded in this way, important warnings can be overlooked in the mass of paperwork. In 2017, for example, an Air Canada plane landed on the wrong runway in San Francisco and narrowly avoided a collision with four other aircraft. The globally standard Notam system is therefore to be overhauled.

A spokesperson for Frankfurt Airport operator Fraport said that the operational impact on flight operations in Frankfurt had so far been minimal. Landings and take-offs by Lufthansa and US airlines are also running as planned in Munich, said an airport spokesperson. A Lufthansa spokesperson explained that the airline's US flights were continuing as planned. "We are not affected by this." Air France also allowed flights to continue taking off, but was monitoring the situation. Some USA flights from Madrid airport were delayed.

By 9.00 a.m. local time on the US East Coast, more than 4,000 flights had been delayed in the USA and around 660 had been canceled, as can be seen on the FlightAware website. United Airlines and other US airlines suspended all domestic flights. According to the flight data portal Cirium, almost 21,500 flights in the USA with around 2.9 million passengers were scheduled for Wednesday.

(Report by David Shepardson, Nathan Gomes, Steve Holland, Abhijith Ganapavaram, Jamie Freed, Rajesh Kumar Singh, Ilona Wissenbach, edited by Scot W. Stevenson; If you have any questions, please contact the editorial team at frankfurt.newsroom@thomsonreuters.com)