Airlines use this term far too broadly. Here is exactly what EU law and European courts say.
An airline may refuse EU261 compensation if the delay or cancellation resulted from "extraordinary circumstances" that could not have been avoided even if all reasonable measures had been taken. However, the European Court of Justice has defined this exception narrowly: a technical fault is almost never extraordinary, nor is a strike by the airline's own staff. The burden of proof rests entirely with the airline — not with you. Never simply accept a refusal citing extraordinary circumstances without verifying the evidence.
Article 5(3) of EU Regulation 261/2004 states that an airline is not obliged to pay compensation if it can demonstrate that the cancellation (or delay) was caused by extraordinary circumstances which could not have been avoided even if all reasonable measures had been taken. Two cumulative conditions: the circumstance must be extraordinary, and the airline must have done everything reasonably possible to limit the consequences.
This is the most commonly misused ground for refusal. Airlines routinely state that the flight was delayed due to "a technical defect on the aircraft." The Court of Justice of the EU ruled explicitly in Wallentin-Hermann v Alitalia (C-549/07, 2008) that technical problems inherent to the normal operation of an airline are not extraordinary circumstances.
The reasoning: an airline that operates aircraft must account for the possibility of technical problems. That risk is part of the business risk. Routine maintenance and repair are normal business activities, not exceptional events.
Only in a very limited situation can a technical problem qualify as extraordinary: if it involves a hidden manufacturing defect that could not have been discovered even through normal maintenance. This is a high bar that the airline itself must prove with documentation from the manufacturer.
The Van der Lans ruling (C-257/14, 2015) confirmed this again: an unexpected technical problem that arose during the flight is not an extraordinary circumstance, even if it was unforeseeable.
This is a nuanced area. The Court has drawn an important distinction:
| Circumstance | Extraordinary? | Notes |
|---|---|---|
| Severe weather (storm, ice, dense fog) | Yes | Must be verifiable via METAR or official report |
| Volcanic eruption (e.g. Eyjafjallajokull 2010) | Yes | NOTAM from Eurocontrol |
| Airspace closure by government authority | Yes | Official decision required |
| Hidden security risk identified by authority | Yes | E.g. unexpected inspection |
| Air traffic control (ATC) restrictions | Sometimes | Structural ATC staff shortages no longer qualify |
| Spontaneous strike by external airport staff | Sometimes | Depends on foreseeability |
| Technical fault (standard) | No | Wallentin-Hermann / Van der Lans |
| Strike by airline's own staff | No | Kruis ruling, CJEU 2018 |
| Technical fault on a previous aircraft (cascade) | No | Cascade delays are an operational business risk |
Airlines sometimes invoke a "cascade": your flight's delay was caused by a delay to an earlier aircraft, which was in turn delayed by something outside their control. But if that earlier aircraft was delayed by a technical fault or organisational cause, the argument fails. The cascade exception only applies if the origin of the cascade was itself a genuine extraordinary circumstance.
This is the most practical point: the airline must prove that extraordinary circumstances existed. You do not have to prove anything. When you receive a rejection citing extraordinary circumstances, always ask:
A vague statement without documentation is not proof. You may resubmit your claim or file a complaint with the national enforcement body if the airline provides no concrete evidence.
Even if the circumstance was extraordinary, the airline must also demonstrate that it took all reasonable measures to avoid the delay or cancellation. Could it have offered rebooking on another flight departing earlier? Could it have deployed a spare aircraft? If the airline failed to use available alternatives, the exception lapses.
Most rejections citing extraordinary circumstances are not backed by concrete evidence. You are not obliged to accept a rejection. Always ask for documentation. You can challenge the rejection yourself for free via the ILT (Netherlands). Alternatively, DelayPaid reviews the rejection on your behalf — 25% success fee incl. VAT, no win no fee.
Use our check tool or send us the refusal letter. We assess whether the stated reason holds up legally.
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