German flag carrier Lufthansa's information technology (IT) systems were largely down on Wednesday, affecting thousands of passenger flights. According to the company, the outage was triggered by damage to fiber optic cables caused by construction work on a railroad line in Frankfurt.
"Unfortunately, this has led to flight delays and cancelations," Lufthansa said via Twitter, without giving exact figures. "We are working on a solution swiftly."
The airline's domestic flights were all cancelled and passengers were asked to switch to trains. In Frankfurt, Germany's largest airport, the airline's departures were all temporarily halted, Xinhua news agency reported.
The fiber optic line was damaged on Tuesday evening, according to Deutsche Telekom AG. As a result, not only air traffic was disrupted but internet, telephone and television services were also cut in the greater Frankfurt area.
"We are continuing to work at full speed on the repair," Deutsche Telekom said on Wednesday via Twitter. "The situation is improving continuously."
A few days earlier, there had already been a large-scale disruption of the Deutsche Telekom network in Dusseldorf due to a similar accident. Around 15,000 internet users were without a connection, including the North Rhine-Westphalia state government.
The flight chaos on Wednesday affected not only Frankfurt but also Munich in particular. Planes were diverted to other airports, such as Nuremberg, Cologne or Dusseldorf. To a lesser extent, the operations of Lufthansa subsidiary airlines Eurowings, Austrian Airlines, Brussels Airlines and Swiss were also hit.
Further air travel disruptions are expected at the end of the week as a wage strike has been announced for Friday, February 17, at various German airports. Lufthansa expects "a large number of flights" to be affected.