In short: A technical fault – whether it comes from wear and tear, a maintenance issue or a part that fails unexpectedly – is not an extraordinary circumstance. If it caused a cancellation at short notice or an arrival delay of 3 hours or more, you can usually claim €250–€600 (EU261) or £220–£520 (UK261). The exceptions are narrow: a hidden manufacturing or design defect revealed by the manufacturer or an authority, sabotage or terrorism, and damage caused from outside, such as debris on the runway.
The rule: technical faults are the airline's risk
Recital 14 of Regulation (EC) No 261/2004 mentions "unexpected flight safety shortcomings" among possible extraordinary circumstances, and airlines often rely on it. The Court of Justice has read it narrowly. In Wallentin-Hermann (C-549/07, 22 December 2008) it held that a technical problem leading to a cancellation is not an extraordinary circumstance "unless that problem stems from events which, by their nature or origin, are not inherent in the normal exercise of the activity of the air carrier concerned and are beyond its actual control".
Airlines face technical problems as a matter of course. Resolving them – through maintenance, spare parts and spare aircraft – is part of the business. The same judgment adds two points airlines often overlook:
- how often an airline has technical problems proves nothing either way; and
- complying with the minimum maintenance rules does not, on its own, show that the airline took all reasonable measures.
The European Commission's 2024 guidelines summarise the position: a technical problem that comes to light during maintenance or is caused by a failure to maintain the aircraft cannot be extraordinary, and neither can one that arises unexpectedly and was not detected during routine checks, if it is inherent in the airline's normal activity.
Is it extraordinary? Technical causes compared
| Cause | Extraordinary? | Authority |
|---|---|---|
| Fault found during maintenance or caused by poor maintenance | No | C-549/07 Wallentin-Hermann |
| Component fails unexpectedly and prematurely, despite correct maintenance | No | C-257/14 van der Lans; Jet2.com v Huzar |
| "On condition" part (replaced only when it breaks) fails, even with a spare in stock | No | C-832/18 Finnair |
| Airport's mobile boarding stairs hit the aircraft | No | C-394/14 Siewert |
| Hidden manufacturing or design defect revealed by the manufacturer or an authority, affecting flight safety | Usually yes | C-549/07 (para. 26); C-411/23; C-385/23 |
| Damage from sabotage or terrorism | Usually yes | C-549/07; C-257/14 |
| Tyre damaged by a foreign object on the runway | Usually yes | C-501/17 Germanwings |
| Runway closed by petrol spilled from another operator's aircraft | Yes | C-159/18 Moens |
| General failure of the airport's refuelling system (where the airport is responsible for it) | Usually yes | C-308/21 SATA |
| Bird strike | Usually yes | C-315/15 Pešková – see bird strikes |
"Usually yes" means the event can qualify; the airline must still prove it caused your delay and that it took all reasonable measures.
The leading cases
Wallentin-Hermann v Alitalia (C-549/07, 2008)
A family booked with Alitalia from Vienna to Brindisi via Rome on 28 June 2005. Five minutes before departure the passengers were told the flight was cancelled, because of a complex engine defect in the turbine found during a check the day before. The Court set out the two-part test still used today and held that the technical problem did not exempt Alitalia unless it stemmed from events outside its normal activity and control. It gave two examples that would qualify: a hidden manufacturing defect affecting flight safety, revealed by the manufacturer or a competent authority across aircraft already in service, and damage caused by sabotage or terrorism.
van der Lans v KLM (C-257/14, 2015)
Ms van der Lans's KLM flight from Quito to Amsterdam in August 2009 arrived 29 hours late. An engine would not start because two components – the engine fuel pump and the hydro-mechanical unit – were defective, and replacements had to be flown in from Amsterdam. KLM argued that the parts had not exceeded their average lifetime and had been checked during maintenance about a month earlier. The Court held that a technical problem which occurred unexpectedly, was not attributable to poor maintenance and was not detected during routine checks is still not an extraordinary circumstance. Aircraft operate in demanding conditions and no component lasts for ever, so such failures are inherent in running an airline.
Jet2.com v Huzar ([2014] EWCA Civ 791)
The leading UK case. Mr Huzar's Jet2 flight LS810 from Malaga to Manchester on 26 October 2011 arrived about 27 hours late after a fuel valve warning on the inbound flight, traced the next day to a wiring defect. The fault was accepted as unforeseen and unforeseeable. The Court of Appeal, applying Wallentin-Hermann, held that technical problems arising in the normal operation of aircraft are inherent in an airline's activity even when unforeseeable, and that whether the airline was at fault is not the test. Jet2 had to pay. The UK Civil Aviation Authority cites Huzar and van der Lans in its own guidance.
Siewert v Condor (C-394/14, 2014)
The evening before a Condor flight from Antalya to Frankfurt, a set of mobile boarding stairs hit the aircraft at Stuttgart Airport and damaged a wing. In an order of 14 November 2014 the Court of Justice held that this was not an extraordinary circumstance: stairs and gangways are indispensable to air transport, so such collisions are part of an airline's normal activity.
Finnair (C-832/18, 2020)
The Court held that the failure of an "on condition" part – one that is replaced only when it becomes defective – is in principle linked to the operating system of the aircraft and is not extraordinary, even if the airline keeps a spare part in stock.
When a technical problem can be extraordinary
Hidden manufacturing or design defects. Two judgments of 13 June 2024 developed the Wallentin-Hermann example. In C-411/23 the engine manufacturer had told the airline months before the flight about a hidden design defect in the high-pressure compressor blades of engines on that aircraft model; the Court held that detecting such a defect is extraordinary even though the airline had been warned. In Finnair (C-385/23), a fuel gauge failure on a new aircraft model, in service for just over five months, before a Helsinki–Bangkok flight in March 2016 was held capable of being extraordinary because the manufacturer later recognised a hidden design defect affecting all aircraft of that type and impinging on flight safety.
What these cases have in common is a defect recognised across a fleet or model by the manufacturer or an authority. A one-off failure of a part on your aircraft does not qualify, even if it was badly made. Even in a hidden-defect case the airline must still show reasonable measures: C-411/23 says this may include keeping a back-up fleet on standby where that is technically and economically feasible.
Sabotage and terrorism. Damage to an aircraft caused by sabotage or terrorism is extraordinary (C-549/07; C-257/14). See security and unruly passengers.
Airport and runway incidents
- Debris on the runway. In Germanwings (C-501/17, 4 April 2019) a screw found in a tyre before a Dublin–Düsseldorf flight meant the tyre had to be changed. Damage from a foreign object on the runway is extraordinary – but the airline must prove it used all its staff, equipment and financial means to stop the tyre change from causing a long delay.
- Petrol on the runway. In Moens v Ryanair (C-159/18, 26 June 2019) a Treviso–Charleroi flight on 21 December 2015 arrived 4 hours 23 minutes late after petrol on the runway closed it for more than 2 hours. That is extraordinary when the petrol did not come from one of the operating airline's own aircraft, and a runway closure decided by the airport authorities could not have been avoided by reasonable measures.
- Airport fuel supply failure. In SATA International (C-308/21, 7 July 2022) a generalised breakdown of the refuelling system at the airport of departure, where the airport was responsible for it, was capable of being extraordinary.
What the airline must prove
- What failed and why – the component, the fault and its origin, normally from the technical log.
- If it relies on a hidden defect: the manufacturer's or authority's notice identifying it across the fleet or model.
- If it relies on an external cause (debris, a third party's vehicle, sabotage): evidence of that cause.
- Reasonable measures: what it did to repair the aircraft quickly, find a spare aircraft, or re-route passengers.
What you can do
- Note what you were told at the gate and by the crew, and keep any texts or emails.
- Ask the airline in writing for the specific fault and its cause. "Technical reasons" is not an answer.
- Claim, citing Wallentin-Hermann (C-549/07), van der Lans (C-257/14) and, for UK261, Jet2.com v Huzar. Our complaint letter template covers this.
- Escalate if the airline refuses without evidence – to the national enforcement body or ADR body of the country where the incident happened for EU, EEA and Swiss flights (see where to complain and our country guides, for example Germany, Spain, France or Italy), or ADR or the CAA for UK flights – see how to claim and the case law library.
UK note: Wallentin-Hermann, van der Lans, Siewert, Germanwings, Moens and Finnair (2020) were decided before the end of 2020 and remain part of how UK courts read UK261. The 2022 and 2024 judgments (SATA, C-411/23, C-385/23) are persuasive in the UK but not binding (Lipton v BA City Flyer [2021] EWCA Civ 454, para. 65).
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Frequently asked questions
The airline says the fault was "for your safety". Does that make it extraordinary?
No. Safety is the reason the aircraft could not fly, not the reason the fault happened. In Wallentin-Hermann (C-549/07) the Court of Justice held that a technical problem is not an extraordinary circumstance unless it stems from events that are not inherent in the airline's normal activity and are beyond its actual control. Finding and fixing faults is part of running an airline.
The part failed unexpectedly even though maintenance was done correctly. Is that extraordinary?
No. In van der Lans (C-257/14) KLM argued that two engine parts had failed before the end of their normal lifetime and had been checked a month earlier. The Court still held this was not extraordinary: no aircraft component lasts for ever, and unexpected failures are inherent in operating aircraft. The English Court of Appeal reached the same view in Jet2.com v Huzar.
What if the manufacturer was to blame?
It depends. A hidden manufacturing or design defect revealed by the manufacturer or an authority and affecting flight safety across a fleet can be extraordinary (C-549/07, C-411/23, C-385/23). A single defective part on one aircraft is not, even if the manufacturer made it. The airline can pursue the manufacturer for its own losses (Article 13); that does not reduce your claim.
A bird hit the engine. Is that a technical fault?
No – a bird strike is treated as an external event and is usually extraordinary (C-315/15 Pešková). The airline must still keep the resulting delay to a minimum. See our guide to bird strikes.
A vehicle at the airport hit our aircraft. Who is responsible?
If it was the airport's mobile boarding stairs, the Court of Justice held that this is not extraordinary, because stairs and gangways are part of normal air transport (C-394/14 Siewert). The Commission's 2024 guidelines describe later rulings in which a collision caused by another airline's aircraft, or by a third party's catering vehicle, was capable of being extraordinary. Ask exactly what hit the aircraft.
How do I find out what the fault was?
Ask the airline in writing for the specific component, when the fault was found and what was done. The Commission's guidelines say evidence such as technical log extracts that the airline relies on should be included in its reply.
General information, not legal advice. We are an independent guide, not lawyers and not AirHelp.
Sources
- Regulation (EC) No 261/2004 – recital 14 and Article 5 (as adopted) – legislation.gov.uk
- C-549/07 Wallentin-Hermann v Alitalia, judgment of 22 December 2008 – Court of Justice of the EU
- C-394/14 Siewert v Condor, order of 14 November 2014 – Court of Justice of the EU
- C-257/14 van der Lans v KLM, judgment of 17 September 2015 – Court of Justice of the EU
- C-501/17 Germanwings, judgment of 4 April 2019 – Court of Justice of the EU
- C-159/18 Moens v Ryanair, judgment of 26 June 2019 – Court of Justice of the EU
- C-832/18 Finnair, judgment of 12 March 2020 – Court of Justice of the EU
- C-308/21 SATA International – Azores Airlines, judgment of 7 July 2022 – Court of Justice of the EU
- C-411/23 D. (hidden engine design defect), judgment of 13 June 2024 – Court of Justice of the EU
- C-385/23 Finnair, judgment of 13 June 2024 – Court of Justice of the EU
- Jet2.com Ltd v Huzar [2014] EWCA Civ 791 – Court of Appeal (England and Wales)
- Lipton v BA City Flyer Ltd [2021] EWCA Civ 454 (status of later CJEU rulings, para. 65) – Court of Appeal (England and Wales)
- Interpretative Guidelines on Regulation (EC) No 261/2004 (C/2024/5687), section 5.2 – European Commission, Official Journal
- Am I entitled to compensation? – UK Civil Aviation Authority
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