Extraordinary circumstances is the only defence that stops a €250, €400 or €600 EU261 payment — £220, £350 or £520 under UK261. It covers events outside the airline’s control under Article 5(3). Most technical faults and the airline’s own staff strikes are not covered, and the airline has to prove it.
What the airline has to show
Article 5(3) of Regulation (EC) No 261/2004 excuses compensation only where the cancellation or long delay was caused by extraordinary circumstances “which could not have been avoided even if all reasonable measures had been taken”. That is two separate things, and the burden for both sits with the airline: an event that is genuinely outside its normal activity, and proof it did what it reasonably could to get you there anyway. A one-word reason does not meet either half. If the airline has already named its reason, the extraordinary-circumstances checker matches it to the Court of Justice judgment that decided it and gives you a paragraph to paste into your reply.
Usually extraordinary — compensation is excused
You still keep care and a refund or re-routing.
- Severe weather that makes the flight unsafe, and airspace closures. In McDonagh v Ryanair (C-12/11, 31 January 2013) the Icelandic ash-cloud closure was extraordinary — and the Court’s point was that the duty to provide care carried on anyway, without a time or money limit.
- Air-traffic-control restrictions and strikes, airport closures, and strikes by people who do not work for the airline.
- Security risks, terrorism and sabotage.
- Bird strikes. Pešková v Travel Service (C-315/15, 4 May 2017) — but the airline must still show it took reasonable preventive and mitigating steps.
- Debris or fuel on the runway. A tyre destroyed by a foreign object was extraordinary in Germanwings v Pauels (C-501/17, 4 April 2019), and petrol spilled on the runway by someone else in Moens v Ryanair (C-159/18, 26 June 2019). In both, the carrier still had to prove it deployed its resources to limit the resulting delay.
- A disruptive passenger forcing a diversion. LE v Transportes Aéreos Portugueses (C-74/19, 11 June 2020) — but only if the carrier did not contribute to the behaviour or fail to anticipate it. The same judgment says putting you on the airline’s own next flight the following day is not automatically a reasonable measure: it has to look at earlier flights, including other carriers’, unless that would be an intolerable sacrifice.
Usually not extraordinary — compensation is owed
- Most technical and mechanical faults. Breakdowns found during maintenance or in service are “inherent in the normal exercise of the activity of the air carrier” — Wallentin-Hermann v Alitalia (C-549/07, 22 December 2008). A fault nobody saw coming is still not extraordinary: van der Lans v KLM (C-257/14, 17 September 2015). This is the most common wrongful refusal on the whole regulation.
- Strikes by the airline’s own staff. A wildcat sickout after a surprise restructuring announcement was not extraordinary in Krüsemann v TUIfly (C-195/17 and joined cases, 17 April 2018), and neither was a lawful union strike by the carrier’s own crew in Airhelp v SAS (C-28/20, 23 March 2021). Whose strike it was is the whole question — see airline strikes versus ATC strikes.
- The airline’s own ground equipment. Boarding stairs colliding with the aircraft were not extraordinary in Siewert v Condor Flugdienst (C-394/14, order of 14 November 2014).
- Crew rostering, staff shortages and knock-on delays from the aircraft’s earlier rotation, unless the original cause was itself extraordinary and directly caused your delay.
- Denied boarding after an earlier disruption. In Finnair v Lassooy (C-22/11, 4 October 2012) a strike had grounded an earlier flight; the carrier bumped a passenger from a later rescheduled one. The Court held that an extraordinary circumstance on the earlier flight does not excuse denied-boarding compensation on the later one.
“Technical issue” and “operational reasons” are not causes. Reply asking the airline to state the specific cause and the reasonable measures it took. If the answer is an ordinary mechanical fault, a crewing problem or its own staff’s strike, restate the claim and escalate to the regulator.
Is bad weather always an extraordinary circumstance?
No. The weather has to have made the flight unsafe or closed the airspace, and the airline still has to show it could not have avoided the delay. If other carriers flew the same route in the same conditions, ask why yours did not, and ask which measures it took.
Does an earlier delay to the same aircraft count?
Only if the earlier disruption was itself extraordinary and there is a direct causal link to your flight. LE v Transportes Aéreos Portugueses accepts that chain, but the airline has to establish it. A knock-on delay from an ordinary problem earlier in the day is not a defence.
The airline says it was extraordinary. What now?
Ask for the specific cause in writing — the get the reason in writing letter makes that request formal — then check it against the two lists above and cite the case by number. If the refusal stands on a bare label, take the file to the national enforcement body or the ADR scheme — see if they refuse.
Rules in force today
This is the law that applies to a flight you take today. A revision of Regulation 261/2004 was adopted in July 2026 — the Parliament approved the conciliation text on 7 July 2026 and the Council gave final approval on 13 July 2026 — and it is not yet in force: it applies 12 months after it enters into force following publication in the Official Journal, and the final text sets the details, including a closed list of extraordinary circumstances. See what the 2026 EU261 reform changes.
These are EU and UK concepts. US flights have no equivalent compensation scheme — see US passenger rights.