"All reasonable measures": the requirement that can defeat a refusal

The wording is decisive. The operating air carrier is not obliged to pay compensation under Article 7 "if it can prove that the cancellation is caused by extraordinary circumstances which could not have been avoided even if all reasonable measures had been taken". That sentence contains two independent requirements, and it is for the carrier to prove that both are met.

The first limb concerns the event: according to the Court of Justice of the EU, only 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 are covered. The second limb concerns the carrier's own conduct: what was done before, during and after the event. A refusal that merely names the cause therefore answers only half of the rule.

The Court of Justice has spelled out what the second limb requires. The carrier must show that it adopted measures appropriate to the situation, deploying all its resources in terms of staff or equipment and the financial means at its disposal in order to avoid the cancellation or long delay of the flight. In the bird-strike case C-315/15, the Court also required the carrier to show that the preventive measures it relies on were actually taken as regards the flight concerned. Pointing to procedures that exist on paper is not sufficient.

The assessment begins before the disruption. In Case C-294/10, Eglītis and Ratnieks v Latvijas Republikas Ekonomikas ministrija, the Court of Justice held on 12 May 2011 that an air carrier must reasonably, at the stage of organising the flight, take account of the risk of delay connected to the possible occurrence of extraordinary circumstances. The carrier must therefore provide for a certain reserve time to allow it, if possible, to operate the flight once the extraordinary circumstances have come to an end.

At the same time, the Court was clear that no general minimum reserve time can be laid down that applies in the same way to all air carriers in all situations. The assessment is made case by case and against the carrier's own capacity: the reserve time must not be of such a length that it leads the carrier to make intolerable sacrifices in the light of the capacities of its undertaking at the relevant time.

The knock-on effects belong to the planning too. The Court gave as examples the reallocation of air corridors and accessibility conditions at the destination airport, including a possible total or partial closure for part of the night, but only in so far as those risks were foreseeable and calculable. That the extraordinary circumstance has come to an end therefore does not settle the matter on its own: the question is also whether the carrier had planned a reasonable reserve time so that it could fly once that was possible again.

The second limb also covers what the carrier does after the disruption. In Case C-74/19, LE v Transportes Aéreos Portugueses SA, the Court of Justice examined on 11 June 2020 a case in which the carrier re-routed the passenger onto a flight operated by itself, arriving the day after the originally scheduled arrival. The Court found that such re-routing cannot, without more, be regarded as a reasonable measure.

Instead, the carrier must consider all the options that produce a shorter delay than its own next flight: direct and indirect flights, including flights operated by other air carriers, whether or not they belong to the same airline alliance. An exception applies where no such alternative exists or where it would involve an intolerable sacrifice for the carrier in the light of the capacities of its undertaking.

That is why the question "which alternatives did you examine?" is at least as important as the question about the cause. If there was a departure the same evening with another carrier, it is for your airline to explain why it was not used.