Has an airline refused compensation after a flight delay or cancellation? Thanks to the European Court of Justice, you can demand at least £225. Barrister Richard Colbey explains

Many passengers who have tried claiming compensation from an airline for a cancelled flight will have encountered refusals based on "exceptional circumstances". Until earlier this month, at least in airline speak, it could mean not only extraordinary events – like the foiled terrorist attack which forced Glasgow airport to close – but technical defects.

European law entitles passengers whose flights are cancelled or substantially delayed to a minimum of €250 (£225) compensation. The airline is only excused liability if it can show its failure was caused by these ill-defined exceptional circumstances.

Friederike Wallentin-Hermann had booked Alitalia tickets for herself, her husband and daughter from Vienna to Brinidisi in south-east Italy, via Rome. The first leg of her flight was cancelled at very short notice, leaving her to take a roundabout route on Austrian Airlines, which resulted in them reaching their destination nearly four hours late.

The cancellation was due to a "complex" turbine engine failure, which took 10 days to fix. Predictably, the airline claimed this was an "exceptional circumstance".

Wallentin-Hermann decided to pursue her claim for the standard compensation, plus a small amount for telephone charges, in her local commercial court. Airlines have tended, since the current compensation regulations were introduced in 2004, not to defend claims from those passengers who actually use the courts.

Most prefer not to risk setting an unfavourable and incontrovertible precedent, which could make it harder to fob off the majority who give up before resorting to litigation.

Alitalia, however, decided to put its head above the pulpit, fighting the matter not only in the Austrian courts, but, when unsuccessful, appealing to the European Court of Justice.

The resulting decision will be welcome confirmation for passengers that routine technical faults are not "exceptional". The court's reasoning recognised that airlines invariably face technical problems. Checking for, and fixing these, is an inherent part of their business. The mere fact that an airline has complied with the legal minimum maintenance requirement will not exempt it from liability when something mechanical goes wrong.

The judgment does not go so far as to rule that mechanical defects could never amount to exceptional circumstances. The court recognised that a warning by the aircraft manufacturer leading to the removal from service of an entire fleet, or mechanical defects caused by terrorists or sabotage, could be treated differently.

The judgment was given in December last year, when it probably became known to the industry, but was only formally published earlier this month. This has a personal resonance, as I suffered a Swiss International Air (SIA) cancellation on Boxing Day due, apparently, to a failed autopilot.

My compensation claim – I only sought out-of-pocket losses, not the full EU set sum – was initially met with the same response as the Wallentin-Hermanns'. A couple of stroppy emails did persuade SIA to pay up, but it was disappointing that the airline continued to argue this issue even after the European Court decision.

Airlines have no excuse now for not paying up; some will doubtless continue to try it on. Anyone encountering this who refers specifically to the "European Court case of Wallentin-Hermann v Alitalia" may impress the airline sufficiently so that it does not waste time trying to bluster its way out of paying up.