CrowdStrike chaos: Why did the global IT outage ground so many planes last week?

23.07.2024 - 23:20 / euronews.com / European Commission

Friday 19 July was set to be one of the busiest days of the summer for Europe’s airports. But the world’s biggest IT outage had other plans for hundreds of thousands of holidaymakers.

A defective software update from cybersecurity firm CrowdStrike was to blame, bringing down the online systems of numerous big and small businesses that use Microsoft services.

Yesterday, Microsoft pointed the finger at the European Commission, saying the bloc’s competition rules prevented it from overriding the update.

While the Big Tech fallout continues, airports and airlines are looking inwards to evaluate how their own contingency plans held up against the calamity. 

Here’s how the disruption unfolded within the aviation world - and why some places were hit harder than others. 

Although the stressful scenes took place inside airports, which quickly filled up with stranded passengers, Friday’s IT outage was primarily an airline problem.

That’s because most airlines rely on Microsoft's Office365 - Cloud-based software - to do their scheduling, getting crew, passengers and bags where they need to be. 

The public-facing side of this is check-ins. When the airlines’ online systems stopped working on Friday morning, they resorted to checking people in manually at airports. Obviously this is a much slower process, which snowballed through their tight schedules. 

There were more than 4,000 flight cancellations and 35,500 flight delays worldwide by Friday afternoon, according to flight tracking firm FlightAware. 

“The IT outage affected multiple systems making it impossible to handle flights,” a spokesperson for Dutch carrier KLM explains. “As soon as it became clear that the computers and laptops running on Windows could not boot up due to the third-party update, we started the backup plan, namely doing processes that could be done manually and at the same time using a workaround to get the machines up and running as soon as possible.”

The outage wreaked havoc with systems optimised for efficiency - and not just for checking in passengers and luggage. 

Airlines outsource a range of jobs to ground handling companies (cabin cleaning, gate security and so on) and some of these firms’ systems were affected too, meaning they struggled to get workers to the right place at the right time.

It was a more mixed picture for the airports themselves. Berlin Brandenburg Airport had issues with its IT systems early on Friday morning that were resolved quicker than some airlines and other airports. Aena, which manages airports in Spain, says its entire network was affected.

But other European airports say it was wholly an airline issue. “Airport systems were not affected in any way, but a ticketing system used by four airlines at the site,” says a