The phrase airlines lean on most when they don't want to pay — and the one most often used incorrectly.
Extraordinary circumstances are events genuinely outside an airline's control that it couldn't have avoided even by taking every reasonable measure — think a genuine security threat, an air traffic control restriction, or severe weather that actually grounds flights. Under Article 5(3) of EU261, if the airline can prove this is what caused your delay or cancellation, it doesn't have to pay compensation. But two things trip airlines up: they carry the burden of proving it, and a long list of things they routinely blame — most notably ordinary technical faults and their own staffing problems — simply don't qualify.
To escape paying compensation, an airline has to show two things, not just one: that the event itself was extraordinary (outside its normal business risk), and that it took all reasonable measures to prevent the disruption or to limit its knock-on effects — for example by trying to source a replacement aircraft or crew. Citing a dramatic-sounding reason isn't enough on its own.
The single most important piece of case law here is Wallentin-Hermann v Alitalia, a case that reached the Court of Justice of the EU after an airline tried to excuse a cancellation by pointing to a technical engine problem. The Court held that technical problems are, in general, an inherent part of operating an aircraft — engines and components fail as a normal feature of running an airline — so a routine technical fault does not count as an extraordinary circumstance. The exception is narrower than airlines often suggest: it can apply where the fault stems from something outside the normal exercise of the airline's activity, such as a manufacturing defect only discoverable during scheduled, mandatory maintenance, or damage from sabotage or an act of terrorism.
A later case involving KLM reinforced the same principle for a part that failed earlier than its expected lifespan — the Court treated this, too, as a foreseeable technical issue rather than something extraordinary, since keeping aircraft airworthy is exactly what airlines are in the business of doing.
Airlines don't always get this distinction right — sometimes because it genuinely is a gray area, sometimes because a boilerplate rejection is cheaper than a proper review. Either way, "the airline said it was extraordinary circumstances" is the start of the conversation, not the end of it. If your claim was rejected on these grounds, it's worth checking the specific reason against how it's actually been treated in case law before accepting it.
Generally no. Under established case law, most technical and mechanical faults are treated as part of the normal exercise of an airline's activity and don't qualify as extraordinary circumstances, even though airlines frequently cite them to avoid paying.
Only if the weather genuinely made the flight unsafe or impossible to operate as scheduled. Airlines sometimes cite weather loosely; it's worth checking what actually happened at the airport and to that specific flight before accepting the reason.
The airline does. It's the airline's burden to show both that extraordinary circumstances occurred and that it took all reasonable measures to avoid the disruption or its knock-on effects.
It can, but it's assessed case by case — a genuine, sudden bird strike causing damage is more likely to qualify than a vaguely described one, and the airline still has to show it took reasonable steps to get you on your way afterward.
Check your flight for free — we'll tell you what you might be owed, even if the airline already said no.