Extraordinary Circumstances: The Complete Passenger Guide

The legal test — two parts, both required

Article 5(3) of EC261 exempts airlines from compensation liability if the delay or cancellation was caused by extraordinary circumstances which could not have been avoided even if all reasonable measures had been taken. Courts have consistently interpreted this as a two-part test: (1) the event must be extraordinary — not inherent to normal airline operations and not within the airline's control — and (2) the airline must have taken all reasonable measures to avoid or mitigate the delay. Both parts must be satisfied.

The burden of proof lies with the airline

This is critical: the airline must prove extraordinary circumstances — you don't need to disprove them. When a rejection letter vaguely states 'extraordinary circumstances' without specifying what they were and what measures were taken, that rejection is vulnerable. Courts expect airlines to produce specific evidence: the ATC restriction notice, the weather report, the security authority communication.

Events that have qualified — the short list

• Genuine bird strikes causing aircraft damage (not foreseeable, not within airline control)
• Extreme weather events outside normal operational parameters (severe volcanic ash, hurricane-force winds closing airports)
• Security threats at airports triggering airspace closure by authorities
• Hidden manufacturing defects discovered mid-operation and not detectable by standard maintenance
• Strikes by external parties (ATC controllers, airport security staff) — with caveats
• Genuine medical emergency on a previous flight requiring diversion

Events that have consistently NOT qualified

• Aircraft technical faults (Wallentin-Hermann, 2008) — inherent to operations
• Airline's own staff strikes (Krüsemann, 2018) — within the airline's sphere
• Late aircraft from previous sector — caused by airline's scheduling decisions
• Staff shortages — foreseeable operational risk
• Ordinary fog, light snow, headwinds within normal parameters
• Fuel price spikes requiring route changes — commercial decision, not extraordinary
• Slot congestion at airports the airline chose to use — foreseeable

The 'reasonable measures' test — often forgotten

Even when the triggering event is genuinely extraordinary, the airline must also show it took all reasonable measures to avoid or reduce the delay. This includes: exploring alternative routings, rebooking on competitor airlines if necessary, repositioning aircraft, or using spare capacity. An airline that does nothing while citing a 2-hour weather window as extraordinary — when the delay stretches to 6 hours — will struggle with this test.

How to challenge an extraordinary circumstances rejection

1. 1Ask the airline in writing: What specific event constituted extraordinary circumstances? What measures did you take?
2. 2Request the full documentation: ATC restrictions, weather authority notices, or other evidence they relied on
3. 3Check flight tracking data — did other flights on the same route operate normally?
4. 4Research the event — was it genuinely exceptional or a routine disruption?
5. 5If the rejection is vague or unsupported, escalate to ADR or court — airlines with weak extraordinary circumstances cases often settle before a hearing