On firmer ground

Deep vein thrombosis hit the headlines five years ago, when an airline passenger's death prompted a string of court cases around the world, resulting in contradictory judgments

In October 2000, a strange thing happened. A seemingly healthy 20-something woman suddenly collapsed after a long-haul flight from Australia. A post-mortem determined that she had succumbed to a clot that had formed in the vein of her leg and was subsequently transported by her blood system to her lungs – causing a pulmonary embolism and her tragic death. Thus, deep vein thrombosis (DVT) entered the public consciousness.

A press furore ensued, with airlines accused of being aware of the problem but failing to warn their passengers. In the opinion of several vocal members of the media and many victims of DVT, airlines had been engaged in a conspiracy of silence.

Meanwhile, some medical researchers were concluding that DVT developed by sitting in a restricted position for a prolonged period would normally lead to a serious consequence only if the victim was predisposed to the condition by one or more medical factors.

Nevertheless, plaintiffs' groups were formed among DVT victims and co-ordinated litigation commenced in the UK and Australia in 2000, followed about a year later by litigation in individual cases in various states in the US.

The Warsaw Convention and the meaning of 'accident'

Claims against airlines for injury arising out of international carriage by air were governed in 2000 by the Warsaw Convention of 1929 as amended, which stipulates that airlines are liable for injuries that occur as a result of accidents that happen on board an aircraft. Lawyers for the plaintiffs sought to prove that the accident was either the occurrence of the DVT itself or causes such as dehydration, increased atmospheric pressure, the restraint of passengers by cramped seating in economy sections of the aircraft and, finally and most importantly, the failure – or inaction – of the airlines to warn of a known risk.

In November 2004, the High Court of Australia, in Povey v British Airways, effectively put an end to DVT cases in that country. Australian judges found, with only one partial dissent, that the failure to warn was a non-event and, if nothing untoward occurred during a flight, this could not be construed to be an accident under the Warsaw Convention.

Meanwhile, a landmark decision by the House of Lords on 8 December, 2005, saw the appeal of DVT claimants in Re: DVT and Air Travel Group litigation unanimously dismissed, knocking out all future DVT litigation in the UK.

Implications for the Warsaw and Montreal conventions

The Lords' decision has several important ramifications. The Warsaw Convention has been replaced by the Montreal Convention of 1999, which came into force in 2002 – after the DVT litigation had already commenced. However, the Montreal Convention still imposes an 'accident' requirement on carrier liability. The Law Lords' decision will be the definitive interpretation of this crucial expression for many years to come in many common law jurisdictions.

The meaning of 'accident' has an importance far beyond DVT for future claimants against carriers and for the airlines themselves. Where there is no 'accident' as defined in the judgment, claimants will not make a recovery, regardless of the circumstances in which they were injured. The ruling endorses the view that an accident must be an unexpected event, external to the passenger and occurring during carriage, and makes clear that a failure to warn of a risk of injury where there is no industry practice of such warnings cannot be an accident.

House of Lords ruling dissents from US Supreme Court decision

The US Supreme Court recently considered a similar question in Husain v Olympic Airways and indicated that the absence of guidance from courts of last resort such as the Australian High Court and the House of Lords left it free to ignore decisions of lower courts. It concluded that in some circumstances an omission to act could be an accident.

Several Law Lords emphasised the need to consider the text of the Warsaw Convention in defining 'accident', as opposed to attempting to glean its meaning by reinterpreting judicial formulations in earlier cases – the approach adopted in Husain.

Lord Scott criticised the approach used in Husain of putting the Convention to one side and concentrating on the judgment in Air France v Saks, an earlier Supreme Court decision defining an accident as "an unexpected or unusual event or happening". He further maintained that the facts in Husain could be distinguished from those in the DVT litigation, citing the decision in Povey regarding the absence of any event – extraordinary or unusual – and thereby implicitly criticised the majority in Husain, who said that the argument that a non-event could not be an accident, was a fallacy.

Lord Mance took a similarly critical approach to the Husain decision. He cited with approval the words of Lord Steyn in Morris v KLM, who observed that it was "not necessarily right to approach the meaning… of the Convention through the spectacles of full corrective justice" in order to find liability on the carrier where it is not permitted by the Convention. The majority in Husain have been criticised for adopting an approach coloured excessively by the unfortunate facts of that case – and might well be regarded as having donned the spectacles described by Lord Steyn.

Lord Mance also criticised any attempt to understand the meaning of 'accident' by reference to the issue of fault, which in the Convention is raised in Article 20 as a defence and in Article 25 as a delimiting provision. The majority in Husain adopted the approach of looking to Article 20 and 25 to interpret Article 17. In contrast, Lord Mance said: "References to fault [such as in failing to warn] can be attractive to the domestic lawyer familiar with contractual or tortious claims for failure to exercise due skill and care. But it is the nature of the event, rather than the care taken to avoid injury, which is the focus of the term 'accident' in Article 17."

In the elliptical language of judicial diplomacy, the House of Lords has addressed the majority in Husain by supporting the proposition that inaction cannot in the normal course of events be an event by citing, with approval, words to that effect in the High Court in Povey and in the dissenting opinion in Husain. Given the clear indication from the Supreme Court that it looked to other courts of last resort on this issue, and the implicit indication that the Supreme Court would support the House of Lords in its search for judicial uniformity, the House of Lords decision gives significant encouragement to airlines seeking to persuade the Supreme Court to revisit its decision in Husain on the correct approach to interpretation of 'accident'.

Impact on pending DVT cases

On the same day that the House of Lords delivered its judgment, Judge Walker in the Northern District of California heard arguments on the motions by airlines for the dismissal of pending DVT actions against international carriers. It is thought that the House of Lords' landmark judgment will be of significant assistance in the defence's arguments before Judge Walker.

As the House of Lords' decision brings to an end the DVT litigation in the UK, apart from one case pending in the Cour de Cassation in France, the issue remains only to be resolved in California. Sean Gates is senior partner of Gates & Partners and co-led the British Airways defence team in the House of Lords.