Long delays when travelling can prove annoying and expensive, which is why EU law sets a schedule of compensation payable to passengers in such circumstances.

However, not all delays give grounds for compensation. The rules exempt airlines from paying compensation to delayed passengers where the delay is the result of ‘extraordinary circumstances’.

As is normal when such terms are not clearly defined, the precise meaning of ‘extraordinary’ ended up being the subject of a dispute, in a case between Dutch carrier KLM and a passenger whose flight from Quito to Amsterdam was delayed for more than 29 hours.

The delay was the result of the unexpected failure of two components – a fuel pump and a hydromechanical unit. Both had been inspected recently and failed well within their expected service life.

This, KLM argued, was an ‘exceptional circumstance’. However the European Court determined that such a failure could not be regarded as ‘extraordinary’ and that compensation was therefore due.

The Court commented that KLM might be able to seek to recover its loss from the manufacturers of the parts concerned, but the practical effect is that it now seems unlikely that airlines will be able to rely on mechanical failures of this nature to withhold compensation for significant flight delays.

In the longer term, the additional costs will almost inevitably fall on the passengers.