Extraordinary Circumstances for Flight Delays (UK261): What Counts in 2026

UK261 (retained from EU Regulation 261/2004) uses the phrase "extraordinary circumstances" to describe events that exempt an airline from paying fixed compensation — not from providing duty-of-care meals and hotels, which still apply in most delay scenarios regardless of cause.

Courts and the Civil Aviation Authority (CAA) interpret the test in three parts. First, the event must be external to the airline's normal operations — not a routine maintenance decision or staffing plan. Second, it must be unforeseeable or unavoidable even if the airline took all reasonable measures (spare aircraft, crew reserves, rebooking options). Third, it must be the direct cause of the delay at your final destination — not a convenient excuse for an underlying operational failure.

If any part of the test fails, compensation is payable at the statutory tiers (£220 / £350 / £260–£520 depending on distance and delay length). Airlines frequently cite extraordinary circumstances in rejection templates without explaining how the test is met — you are entitled to ask for evidence.

Severe weather that makes flying unsafe — storms, heavy snow closing runways, volcanic ash, extreme crosswinds beyond aircraft limits — is the most common valid exemption. A light drizzle or moderate wind that other flights handled does not qualify; airlines must show conditions were genuinely incompatible with safe operation.

Strikes by third parties are generally extraordinary: air traffic control industrial action, airport ground-handler walkouts, border-force strikes, and security staff stoppages. The strike must not be by the airline's own pilots or cabin crew — those are treated as within the airline's control because staffing is a core operational responsibility.

Security threats, acts of sabotage or terrorism, political instability closing airspace, and sudden airport closures ordered by authorities also qualify. Hidden manufacturing defects — a manufacturer-issued fleet-wide grounding affecting an entire aircraft type — can exempt the airline, but a fault on one aircraft that routine maintenance should have caught does not.

Bird strikes sit in a grey zone. UK and EU courts have sometimes treated them as extraordinary when they force an immediate return or long inspection, but airlines cannot automatically reject every bird-strike delay — the outcome depends on whether reasonable measures could have prevented the disruption to your particular flight.

Technical and mechanical faults are the most litigated category. The landmark UK case Huzar v Jet2 (2014) established that ordinary technical problems are inherent to running an airline and are not extraordinary — the carrier is expected to maintain aircraft and hold spare parts. Airlines still reject claims citing "technical reasons" without distinguishing a hidden manufacturing defect from routine wear.

Crew sickness and staff shortages are not extraordinary. UK and EU courts have repeatedly held that illness among pilots and cabin crew is part of normal airline operations — the airline must roster reserves. Rejections citing "crew unavailability" or "operational reasons" without detail should be challenged; 2024–2025 court activity further narrowed airlines' ability to use sickness as a blanket defence.

Late arrival of the inbound aircraft (knock-on delay) is not extraordinary unless the previous flight's delay itself was caused by an extraordinary event. If your London–Dubai flight is delayed because the aircraft arrived late from Paris due to a technical fault, the airline owes compensation — the chain of causation stays within its control.

IT system failures, check-in software outages, baggage-loading delays, catering problems, and overbooking fallout are operational issues, not extraordinary circumstances. The same applies to fueling delays and cleaning overruns unless caused by an external event (e.g. fuel supply strike).

Weather rejections deserve scrutiny. Compare your flight to others on the same day: if most departures operated and only your carrier cancelled, the problem may be crew or fleet scheduling dressed up as weather. Flight-tracking sites and airport METAR reports (official weather observations) help you verify whether conditions genuinely closed the airport or just your airline's operation.

ATC strikes are extraordinary; airline-pilot strikes are not. When French ATC strikes ripple delays across Europe, UK261 compensation may not apply to the knock-on delay — but duty-of-care meals and hotels still do. When BA or easyJet crew strike over pay, compensation is typically owed because the dispute is between the airline and its employees.

Airlines must prove extraordinary circumstances — you do not have to disprove them. Ask the airline to specify the exact event, date, and why reasonable measures could not avoid your delay. Generic phrases like "due to circumstances beyond our control" are insufficient for a valid rejection under CAA guidance.

Reply in writing requesting the specific extraordinary circumstance, documentary evidence (NOTAMs, strike notices, maintenance logs redacted as necessary), and an explanation of why all reasonable measures were exhausted. Set a deadline — 14 days is reasonable for a substantive response.

If the airline maintains the rejection, escalate to its Alternative Dispute Resolution (ADR) scheme or complain to the CAA. ADR adjudicators apply the same legal test and frequently overturn vague extraordinary-circumstances defences — particularly for technical faults and crew sickness.

For the full escalation path including ADR schemes by airline and small-claims court thresholds, see /guides/flight-delay-claim-rejected-appeal-uk-2026. For the parent UK261 guide with compensation tiers and step-by-step filing, see /guides/uk261-flight-delay-compensation-uk.