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Judgments - Deep Vein Thrombosis and Air Travel Group Litigation (8 actions) (formerly 24 actions)


SESSION 2005-06

[2005] UKHL 72

on appeal from: [2003] EWCA Civ 1005




for judgment IN THE CAUSE



Deep Vein Thrombosis and Air Travel Group Litigation

(8 actions) (formerly 24 actions)





Appellate Committee


Lord Scott of Foscote

Lord Steyn

Lord Walker of Gestingthorpe

Baroness Hale of Richmond

Lord Mance





Anthony Scrivener QC

Wayne Beglan

(Instructed by Collins)



Robert Webb QC

Robert Lawson

(Instructed by Gates & Partners for British Airways)

Robert Lawson

(Instructed by Clyde & Co for China Airlines)


Hearing dates:

19 and 20 October 2005




Thursday 8 DECEMBER 2005





Deep Vein Thrombosis and Air Travel Group Litigation (8 actions) (formerly 24 actions)

[2005] UKHL 72


My Lords,


    1.  This litigation has raised once again, albeit in a fairly new context, the question as to the scope that should be given to the term "accident" in article 17 of the Warsaw Convention 1929. The purpose of the Convention, as my noble and learned friend Lord Steyn has observed, was "to bring some order to a fragmented international aviation system by a partial harmonisation of the existing law" (para 27) of his opinion repeating his comment in Morris v KLM Royal Dutch Airlines [2002] AC 628, 635). It is common ground, therefore, that it is important that the courts of the respective signatory states should try to adopt a uniform interpretation of the Convention.

    2.  Article 17 set out the basis on which a carrier would be liable for bodily injury sustained by a passenger during the flight (or while embarking or disembarking from the aircraft). The Convention underwent amendment at the Hague in 1955 but none of the amendments affect the point now in issue. The Convention as amended was incorporated into domestic law by the Carriage of Air Act 1961 and is set out in the 1st Schedule to that Act.

    3.  Article 17 provided as follows:-

    "The carrier is liable for damage sustained in the event of the death or wounding of a passenger or any other bodily injury suffered by a passenger, if the accident which caused the damage so sustained took place on board the aircraft or in the course of any of the operations of embarking or disembarking."

It is to be noticed that the conditions for the imposition of liability on the carrier do not include any element of fault or blameworthiness or failure to observe a proper standard of care on the part of the carrier. The requirements of liability are, first, that the passenger has suffered a bodily injury (a requirement that gives rise to questions about psychiatric injury which, happily, do not need to be addressed in the present case), second, that the bodily injury has been caused by an "accident" and, third, that the accident took place on board the aircraft (or in the process of embarkation or disembarkation). The omission from these conditions of any requirement of negligence on the part of the carrier is double-edged so far as an injured passenger is concerned. It is to the passenger's advantage that negligence on the part of the carrier needs to be neither alleged nor proved. It is to the passenger's disadvantage, however, that even clear causative negligence on the part of the carrier will not entitle the passenger to a remedy if the article 17 conditions cannot be satisfied. It has been authoritatively established that if a remedy for the injury is not available under the Convention, it is not available at all (see Sidhu v British Airways plc [1997] AC 431 and El Al Israel Airlines Ltd v Tsui Yuan Tseng 525 US 155 (1999)).

    4.  Nonetheless, negligence, or the absence of it, on the part of the carrier may play a part under article 20. Article 20 provided that :

    "The carrier is not liable if he proves that he and his servants or agents have taken all necessary measures to avoid the damage or that it was impossible for him or them to take such measures."

Plainly, a carrier who had been negligent could not qualify for an Article 20 defence.

    5.  Contributory fault of the injured person, too, may afford a defence to the carrier. Article 21 provided that:

    "If the carrier proves that the damage was caused by or contributed to by the negligence of the injured person the court may, in accordance with the provisions of its own law, exonerate the carrier wholly or partly from his liability."

I should mention also article 22 which imposes monetary limits on the extent of the liability of the carrier for article 17 damage. It has often been observed that the provisions were designed to strike a balance between the interests of passengers and the interests of the airlines. (See e.g. Morris v KLM Royal Dutch Airlines [2002] AC 628 per Lord Hope of Craighead at para. 66).

    6.  The use in article 17 of the term "accident" is to be contrasted with the choice of a different term in article 18. Article 18 imposes liability on carriers for damage to baggage or cargo:

    "The carrier is liable for damage sustained in the event of the destruction or loss of, or of damage to, any registered baggage or any cargo, if the occurrence which caused the damage so sustained took place during the carriage by air." (emphasis added)

    7.  The use of the term "accident" in article 17 but the term "occurrence" in article 18 must be significant. Both terms impart the idea that something or other has happened. But "occurrence" is entirely general in its natural meaning. It permits no distinction to be drawn between different types of happening. "Accident" on the other hand must have been intended to denote an occurrence of a particular quality, an occurrence having particular characteristics. In the many decided cases in which the issue was whether the occurrence in question constituted an "accident" for article 17 purposes, the judges have had to ask themselves whether the occurrence possessed the necessary quality or characteristics to qualify as an "accident". It is evident that it was never, or should never have been, enough for there to have been an occurrence that caused the damage. For article 17 liability the occurrence had to have the characteristics of an "accident".

    8.  The "fairly new context" to which I referred in paragraph 1 is the growing belief that sitting in a cramped position for many hours may give rise to the formation of small blood clots in the deep veins of the legs, hence, deep vein thrombosis (DVT). For obvious reasons DVT in relation to air travel is sometimes referred to as "economy class syndrome". If blood clots break away from the wall of the vein to which they are attached and are carried along with the flow of the blood, serious complications may ensue, including a stroke, a heart attack or, in the worst cases, death. As long ago as 1976 a passenger claimed to have suffered from deep vein thrombosis brought about by a long distance flight. But the Supreme Court of New York held that the condition had not been caused by an article 17 "accident" and the passenger's damages claim failed (see Scherer v Pan American World Airways Inc. (1976) 387 N.Y.S.2d 580). Since then DVT as an alleged consequence of economy class long distance flights has had increasing attention from the media, from members of the medical professions and from airlines themselves. The hand baggage of most passengers on long distance flights will these days include a pair of tight stockings which, if worn, are believed to provide some protection against the onset of DVT. Many air travellers, however, have suffered the serious consequences of DVT to which I have referred and they, or persons on their behalf, believe the onset of the DVT to have been attributable to the nature of the seating provided for them on the aircraft.

    9.  Litigation has therefore taken place in a number of jurisdictions raising the question whether the onset of DVT in the course of and caused by air travel can constitute an "accident" for article 17 purposes. Litigation by a number of claimants has been commenced in this jurisdiction. They allege that they, or their deceased relatives, have suffered DVT caused by their flying on an aircraft operated by one or other of the respondents, each of which is a commercial airline. They say that the DVT was caused by an "accident" within the meaning of article 17. A Group Litigation Order in respect of these actions was made on 8 March (and amended on 10 March) 2002 and on 10 May 2002 an order was made by the Senior Master directing that a preliminary issue of law be determined on the basis of an agreed "specimen matrix" of fact.

    10.  The preliminary issue was:

    "whether the onset of deep vein thrombosis (DVT) sustained during the course of, or arising out of, international carriage by air, whether as result of an act and/or omission of the carrier or otherwise, is capable, in principle, of being 'an accident' causing bodily injury within the meaning of article 17 of the Warsaw Convention."

The specimen matrix is important. Paragraph 1 describes DVT; paragraph 2 describes characteristics of individuals that may predispose them to the onset of DVT. These details are not important for present purposes. Paragraph 3 simply says that the "Defendant is a commercial air carrier". I should, however, set out in full the remaining paragraphs:

    "4.  The Claimant was carried by air by the Defendant, for reward, on an international flight to which the provisions of the Warsaw Convention applied. The flight was characterized by the following features:

    (1)  the layout of the passenger cabin, the seating space available to each passenger and the type of passenger seat installed on the aircraft performing the flight were all in accordance with the Defendant's usual standard for an aircraft of that type flying on the route in question;

    (2)  the flight was operated in accordance with all of the Defendant's usual procedures and practices;

    (3)  nothing happened in the course of the flight which adversely affected the performance or flight characteristics of the aircraft;

    (4)  throughout the flight all of the aircraft's seating and all of its systems affecting the passenger cabin environment were in their normal working order;

    (5)  the aircraft complied with, and the flight was carried out in accordance with, all applicable aviation regulations; and,

    (6)  whether or not the above operation of the aircraft minimized and/or eliminated the risk of passengers suffering from DVT, the Defendant took no further or other steps to minimize and/or eliminate such risk.

    5. The Claimant asserts that there is a causal link between air travel and the onset of DVT. The defendant denies the existence of any such link. For the purpose of this specimen matrix alone it is assumed that the Claimant suffered from a symptomatic DVT caused by the flight.

    6. The Claimant asserts that the Defendant knew, or ought to have known, prior to the flight that by virtue of carriage by air passengers would be at an increased risk of suffering DVT over and above that incurred in everyday life. The Defendant denies these assertions. For the purpose of this specimen matrix alone it is assumed that the Claimant's assertions are correct.

    7. The Defendant did not give the Claimant any warning as to the risk assumed in paragraph 6 above, or any advice as to how to minimize any such risk, at any time before or during the flight."

These are the assumed facts on the basis which the preliminary question was to be answered.

    11.  Counsel for the parties were in broad agreement as to the principles of interpretation of article 17 that should be applied. The important principles for present purposes are that:

    (1)  the starting point is to consider the natural meaning of the language of article 17, with the French text prevailing in case of any inconsistency with the English text (fortunately there is no relevant inconsistency);

    (2)  the Convention should be considered as a whole and given a purposive interpretation;

    (3)  the language of the Convention should not be interpreted by reference to domestic law principles or domestic rules of interpretation; and

    (4)  assistance can and should be sought from relevant decisions of the courts of other Convention countries, but the weight to be given to them will depend upon the standing of the court concerned and the quality of the analysis.

    I would add to these that the balance struck by the Convention between the interests of passengers and the interest of airlines ought not to be distorted by a judicial approach to interpretation in a particular case designed to reflect the merits of that case. The point was well put by Justice Scalia in his dissenting opinion in Husain v Olympic Airways (2004) 124 S.Ct. 1221, 1234 (an opinion with which Justice O'Connor concurred):

    "A legal construction is not fallacious merely because it has harsh results. The Convention denies a remedy, even when outrageous conduct and grievous injury have occurred, unless there has been an 'accident'. Whatever that term means, it certainly does not equate to 'outrageous conduct that causes grievous injury'. It is a mistake to assume that the Convention must provide relief whenever traditional tort law would do so. To the contrary, a principal object of the Convention was to promote the growth of the fledgling airline industry by limiting the circumstances under which passengers could sue. .. Unless there has been an accident there is no liability, whether the claim is trivial ….. or cries out for redress".

    12.  I think at this point a word of caution about the process of interpretation is in order. It is not the function of any court in any of the Convention countries to try to produce in language different from that used in the Convention a comprehensive formulation of the conditions which will lead to article 17 liability, or of any of those conditions. The language of the Convention itself must always be the starting point. The function of the court is to apply that language to the facts of the case in issue. In order to do so and to explain its decision, and to provide a guide to other courts that may subsequently be faced with similar facts, the court may well need to try to express in its own language the idea inherent in the language used in the Convention. So a judge faced with deciding whether particular facts do or do not constitute an article 17 accident will often describe in his or her own language the characteristics that an event or happening must have in order to qualify as an article 17 accident. But a judicial formulation of the characteristics of an article 17 accident should not, in my opinion, ever be treated as a substitute for the language used in the Convention. It should be treated for what it is, namely, an exposition of the reasons for the decision reached and a guide to the application of the Convention language to facts of a type similar to those of the case in question.

    13.  In Fenton v J.Thorley & Co [1903] AC 443, 453 Lord Lindley said that an "accident" was not a technical legal term with a clearly defined meaning. He went on:

    "Speaking generally … an accident means any unintended and unexpected occurrence which produces hurt or loss. But it is often used to denote any unintended or unexpected loss or hurt apart from its cause; and if the cause is not known the loss or hurt itself would certainly be called an accident."

The issue in Fenton v J.Thorley & Co was whether a workman had suffered an "injury by accident" for the purposes of the Workman's Compensation Act 1897. The context was very different from that of the Warsaw Convention. Nonetheless Lord Lindley's understanding of what "accident" meant in the ordinary use of the English language is a useful starting point and was treated as that by Justice O'Connor in giving the highly influential opinon of the U.S. Supreme Court in Air France v Saks 470 US392 (1985) (see at p.398).

    14.  But set in the context of the Convention some adjustments to Lord Lindley's definition of "accident" are clearly necessary. First, for Convention purposes the "loss or hurt" cannot itself be the "accident". Article 17 distinguishes between the bodily injury on the one hand and the "accident" which was the cause of the bodily injury on the other. It is the cause of the injury that must constitute the "accident". Second, it is important to bear in mind that the "unintended and unexpected" quality of the happening in question must mean "unintended and unexpected" from the viewpoint of the victim of the accident. It cannot be to the point that the happening was not unintended or unexpected by the perpetrator of it or by the person sought to be made responsible for its consequences. It is the injured passenger who must suffer the "accident" and it is from his perspective that the quality of the happening must be considered.

    15.  In Air France v Saks 470 US 392 Justice O'Connor, having cited Lord Lindley's definition of an "accident", having surveyed the French case-law and dictionaries and having reviewed the history of the negotiations that had led to the Convention, concluded at p.405:

    "… liability under Article 17 of the Warsaw Convention arises only if a passenger's injury is caused by an unexpected or unusual event or happening that is external to the passenger. This definition should be flexibly applied after assessment of all the circumstances surrounding a passenger's injuries."

    16.  Two features of this conclusion, both of which can be regarded as prompted by the facts of the Saks case, warrant some comment. The facts were these. The claimant had suffered damage to and become permanently deaf in an ear as a result of pressurisation changes while the aircraft was descending to land. But the pressurisation system of the aircraft had operated in an entirely normal manner. The airline contended that the normal operation of a normal pressurisation system could not qualify as an article 17 accident. Justice O'Connor agreed. The damage to the claimant's ear could not itself constitute the article 17 accident. The cause of the damage had to be the accident. But the pressurisation system had operated normally. This is the factual background that led Justice O'Conner to formulate the requirement of an "unexpected or unusual event or happening that is external to the passenger" (emphasis added). In doing so she noted that

    "European legal scholars have generally construed the word 'accident' in Article 17 to require that the passenger's injury be caused by a sudden or unexpected event other than the normal operation of the plane" (p.404)

and that

    "American decisions …. while interpreting the term 'accident' broadly …. nevertheless refuse to extend the term to cover routine travel procedures that produce an injury due to the peculiar internal condition of a passenger" (p.404/5).

    17.  Both the requirement that the causative event be unusual and that it be external to the passenger were prompted by the facts of the Saks case. Both requirements were emphasised by Justice O'Connor in passages at page 406 of her opinion:

    "… when the injury indisputably results from the passenger's own internal reaction to the usual, normal and expected operation of the aircraft, it has not been caused by an accident and Article 17 of the Warsaw Convention cannot apply."


    "Any injury is the product of a chain of causes, and we require only that the passenger be able to prove that some link in the chain was an unusual or unexpected event external to the passenger."

    18.  O'Connor J's opinion in Saks has been widely followed both in the United States and in the courts of other signatory states. Both the standing of the court and the reasoning of the opinion justify that reliance. Moreover, as I have already observed, it is of importance that if possible a uniform interpretation of the Convention should be applied in all signatory states.

The DVT cases

    19.  There have been attempts by claimants in several signatory states to establish article 17 liability for DVT brought about, or said to be brought about, by air travel. I have already referred to Scherer v Pan American Airways Inc 387 NYS 2d 580 in which a DVT article 17 claim was rejected by the Supreme Court of New York. In October 2001 a similar claim was rejected by the Frankfurt Main Regional Court (see Shawcross & Beaumont's Air Law, loose leaf edition para.702). Article 17 claims based on the airline's failure to warn passengers of the possibility of, and the need to take precautions against, DVT have been rejected in Australia, Canada, Germany and the United States. Some decisions to the contrary can be found but the bulk of the authority is firmly against the acceptance of article 17 DVT claims.

    20.  The most important DVT authority is the recent decision of the High Court of Australia in Povey v Qantas Airways Ltd [2005] HCA33. Gleeson CJ and Gummow, Hayne and Haddon JJ gave a judgment rejecting the argument that the onset of DVT brought about by the conditions of passenger travel on the flight could be said to have been caused by an article 17 accident. The onset of DVT, ie. the formation of the blood clots in the veins of the leg, could not be the requisite accident because that onset was the damage, or the first stage of the damage, complained of. And no other event or happening, no occurrence external to the passenger, could be pointed to. It was common ground that "nothing happened on board the aircraft which was in any respect out of the ordinary or unusual" and "the relevant flight conditions were not said to be unusual or unexpected in any respect (p.13). Kirby J and Callinan J gave concurring judgments.

    21.  I should mention also the recent US Supreme Court decision in Olympic Airways v. Husain 124 S.Ct. 1221 (2004). This was not a DVT case. An asthma sufferer, to whom ambient cigarette smoke represented a considerable health risk, asked for and was allocated seats for himself and his wife in the non-smoking section of the aircraft. Once aboard the aircraft he realised that the allocated seats were only three rows away from the smoking section. He, or his wife, asked a flight attendant if he could move to a seat further away from the cigarette smokers. The flight attendant said no other seats were available. This was untrue. During the flight the asthma sufferer became affected by ambient smoke from the smoking section and suffered a serious asthma attack from which he died. A claim was made by his widow under article 17. The issue was whether his death had been caused by an article 17 accident. But for the intervention, as a link in the causal chain, of the exchanges between the asthma sufferer (or his wife) and the flight attendant the case would have been difficult to distinguish from the DVT cases. The issue was whether that link made all the difference. The majority of the Supreme Court, concurring in an opinion delivered by Justice Thomas, held that it did. They accepted the argument that her failure to move the asthma sufferer to an available seat further away from the smoking section was a cause of the damage external to the passenger and, since it was contrary to normal airline industry standards, was therefore neither expected nor usual. They endorsed O'Connor J's Saks criteria but said that a plaintiff need only be able to prove that "some link in the [causation] chain was an unusual or unexpected event external to the passenger" (p.1227). They rejected the argument that the flight attendant's failure to act could not constitute an "event or happening". Dictionary definitions of "event" or "happening" were cited and relied on. The proposition that an article 17 accident could not be produced by mere inaction was rejected as a "fallacy" (p.1229). Justice Scalia gave a dissenting opinion with which Justice O'Connor, as to its important parts, expressed her agreement. The dissent was as to whether the inaction of the flight attendant could constitute an article 17 accident.

    22.  There is no corresponding problem to be resolved in the present case and it is not necessary for your Lordships in this case to express any preference between the majority and dissenting opinions in Husain. I venture, however, to express my respectful disagreement with an approach to interpretation of the Convention that interprets not the language of the Convention but instead the language of the leading judgment interpreting the Convention. This approach tends, I believe, to distort the essential purpose of the judicial interpretation, namely, to consider what "accident" in article 17 means and whether the facts of the case in hand can constitute an article 17 accident.

    23.  Of more importance for present purposes is that nothing in the Husain case casts doubt upon the two important requirements of an article 17 accident that were established in Saks and have been applied fairly consistently ever since, namely, that an event or happening which is no more than the normal operation of the aircraft in normal conditions cannot constitute an article 17 accident and, second, that the event or happening that has caused the damage of which complaint is made must be something external to the passenger.

    24.  These two requirements appear to me to rule out article 17 recovery in DVT cases where no more can be said than that the cramped seating arrangements in the aircraft were a causative link in the onset of the DVT. The failure by an airline to warn its passengers of the danger of DVT and of the precautions that might be taken to guard against that danger does not, in my opinion, improve the case, at least where there is no established practice of airlines generally or of a defendant airline in particular to issue such warnings. How the case would look if there were such an established practice and if by an oversight the usual warnings were not given does not arise for consideration in the present case. The specimen matrix includes no such assumed facts.

    25.  Accordingly for these reasons, as well as those of my noble and learned friends Lord Steyn and Lord Mance, I would dismiss this appeal.


My Lords,

    26.  The question is whether the onset of deep vein thrombosis ("DVT") sustained during the course of, or arising out of, international carriage of goods by air can amount to an accident within the meaning of article 17 of the Warsaw Convention of 1929 as amended at The Hague in 1955 and incorporated in English law as schedule 1 to the Carriage by Air Act 1961. For the present purposes it is unnecessary to consider separately article 17(1) of the Montreal Convention 1999 (Carriage by Air Act 1961, schedule 1B as inserted by S.I. 2002/263).

    27.  The purpose of the Warsaw Convention, following the precedent of the earlier Hague Rules governing carriage by sea, was to bring some order to a fragmented international aviation system by a partial harmonisation of the applicable law. The Warsaw Convention is an exclusive code of limited liability of carriers to passengers. On the other hand, it enables passengers to recover damages even though, in the absence of the Convention and the Act, they might have no cause of action which would entitle them to succeed. It follows from the scheme of the Convention, and indeed from its very nature as an international trade law convention, that the basic concepts it employs to achieve its purpose are autonomous concepts. For present purposes the compromise agreed at Warsaw involved the imposition of a form of strict liability on carriers in respect of accidents causing death, wounding or bodily injury to passengers in return for the limitations of liability expressed in the Warsaw Convention.