Air Link Pty Ltd v Paterson

Reported Decision: 75 NSWLR 354233 FLR 416[2010] ALMD 3505

CITATION: Air Link Pty Ltd v Paterson [2009] NSWCA 251

JUDGMENT OF: Allsop P at 1; Ipp JA at 1; Sackville AJA at 95

CATCHWORDS: AVIATION - carriage by air - carriers' liability - statutory liability of carrier for personal injury suffered by passenger - Civil Aviation (Carriers' Liability Act) 1959 (Cth) s28 - construction to recognise international source of terms used by Parliament - Convention for the Unification of Certain Rules Relating to International Transportation (Warsaw Convention) Article 17 - Hague Protocol - Montreal Protocol - injury occurred while passenger disembarking from small aeroplane - whether accident cause of injury - required externality - unusual, unexpected and external event - discharge of onus of proof can occur in circumstances where precise character and details of the external event are not proved - DAMAGES - general damages - whether pre existing condition - injury aggravated pre-existing knee injury - injury to other knee as a result - use of expert evidence - expert evidence subject to rational analysis - clear explanation as to why unable to resolve differences between experts - rule in Watts v Rake - DAMAGES - pure economic loss - evidence capable of supporting case for loss of economic capacity - finding of trial judge based on the evidence - WORDS AND PHRASES - "accident" - Civil Aviation (Carriers' Liability Act) 1959 (Cth) - s28

Australian Constitution Civil Aviation (Carriers' Liability) Act 1959 (Cth) Civil Liability Act 2002 LEGISLATION CITED: Judiciary Act 1903 (Cth) Warsaw Convention (Convention for the Unification of Certain Rules Relating to International Transportation by Air, October 1926) Hague Protocol of 1955 Montreal Protocol No 4 of 1975 1999 Montreal Convention for the Unification of Certain Rules for International Carriage by Air

Agtrack (NT) Pty Ltd v Hatfield [2005] HCA 38; 223 CLR 251 Air France v Saks 470 US 392 (1985) Barclay v British Airways Plc [2008] EWCA Civ 1419; [2009] 1 All ER 871 EMI Australia Ltd v BES [1970] 2 NSWR 238 Fernandez v Tubemakers of Australia Ltd [1975] 2 NSWLR 190 Fenton v J Thorley & Co Limited [1903] AC 443 Garcia Ramos v Transmeridian Airlines 385 F Supp 2d 137 (2005 D. Puerto Rico) Fulop v Malev Hungarian Airlines (2001) 175 F Supp 2d 651 Gotz v Delta Air Lines Inc 12 F Supp 2d 199 (1998 D. Mass) Gulf Air Company GSC v Fattouh [2008] NSWCA 225; 251 ALR 183 In re Deep Vein Thrombosis and Air Travel Group Litigation [2003] EWCA Civ 1005; [2004] QB 234 In re Deep Vein Thrombosis and Air Travel Group Litigation [2005] UKHL 72; [2006] 1 AC 495 Kotsambasis v Singapore Airlines Ltd (1997) 42 NSWLR 110 CASES CITED: Malaysian Airline Systems Berhad v Krum [2005] VSCA 232 Olympic Airways v Husain 540 US 644 (2004) Povey v Qantas Airways Limited [2005] HCA 33; 223 CLR 189 Purkess v Crittenden [1965] HCA 34; 114 CLR 164 Sethy v Malev Hungarian Airlines Inc 2000 US Dist Lexis 12606 Seltsam Pty Ltd v McGuiness [2000] NSWCA 29; 49 NSWLR 262 Sharma v Virgin Atlantic Airways 2006 US Dist Lexis 20127 Sidhu v British Airways plc [1997] AC 430 South Pacific Air Motive Pty Ltd v Magnus [1998] FCA 1107; 87 FCR 301 Sydney South West Area Health Service v Stamoulis [2009] NSWCA 153 Watts v Rake [1960] HCA 58; 108 CLR 158 Waxman v CIS Mexicana De Aviacion SA (1998) 13 F Supp 2d 508 Wiki v Atlantis Relocations (NSW) Pty Ltd [2004] NSWCA 174; 60 NSWLR 127 Zurich Australian Insurance Ltd v Raman; Gyimah v Mackay [2009] NSWCA 221

TEXTS CITED: Commonwealth Senate, Parliamentary Debates (Hansard) 25 February 1959 Harold Luntz, Assessment of Damages for Personal Injury and Death, 4th ed (2002)

PARTIES: Air Link Pty Ltd Malcolm Ian Paterson

COUNSEL: R Williams QC; D Stanton (Appellant) J Sexton SC; P Regattieri (Respondent)

SOLICITORS: Norton White Lawyers (Appellant) M J Duffy & Son Solicitors (Respondent)

LOWER COURT JURISDICTION: District Court

LOWER COURT JUDICIAL OFFICER: Elkaim SC DCJ

LOWER COURT DATE OF DECISION: 4 November 2008

LOWER COURT MEDIUM NEUTRAL CITATION: Paterson v Air Link Pty Ltd [2008] NSWDC 241

IN THE SUPREME COURT OF NEW SOUTH WALES COURT OF APPEAL 40407/08

ALLSOP P IPP JA SACKVILLE AJA

Thursday 20 August 2009 AIR LINK PTY LTD v PATERSON

The respondent (plaintiff below) fell at Dubbo airport while disembarking from a small passenger aeroplane operated by the appellant.

The rear exit of the aeroplane had a set of steps which folded out, but which did not reach the ground, so a lightweight aluminium step was placed below the aeroplane's steps to allow passengers to disembark. While disembarking the respondent fell forward striking his knees on the tarmac. He later suffered significant problems with his knees.

The respondent claimed damages in the District Court of NSW under the Civil Aviation (Carriers' Liability) Act 1959 (Cth), s28.

The primary judge held that the respondent's injury was suffered by him as a result of an "accident" for the purposes of Civil Aviation (Carriers' Liability) Act s 28 and therefore that the carrier was liable. The judge found that while the respondent was disembarking the step moved, though he could not conclude what caused the movement. The respondent was awarded both general damages and damages for loss of economic capacity.

The issues on appeal were: 1. whether the trial judge erred in finding that what had occurred was an "accident" covered by the Civil Aviation (Carriers' Liability) Act, s 28 and Convention for the Unification of Certain Rules Relating to International Transportation (Warsaw Convention) Article 17;

2. whether the finding of the trial judge was available on the evidence because it had not been proved at trial what caused the lightweight step to move;

3. whether the primary judge had failed to correctly deal with the expert evidence when awarding general damages;

4. whether the findings of the trial judge in relation to loss of economic capacity were supported by the evidence.

The primary judge did not err in finding there was liability under Civil Aviation (Carriers' Liability) Act because what happened involved an "accident" covered by s 28.

Allsop P and Ipp JA (with whom Sackville AJA agreed generally): i) Section 28 is to be construed recognising the international instrument from which it is sourced that being the Warsaw Convention, Article 17: [5]

ii) For an injury to be caused by an "accident" covered by s 28 there is a requirement that the passenger's injury was caused by an unexpected or unusual event external to the passenger: [14]-[15], [23]-[25]

iii) The required externality of the event does not exclude from the definition of "accident" an event which involves the participation of the passenger, as long as the event was unexpected or unusual and caused otherwise than by the passenger: [31]

iv) The sudden movement of the step was unexpected, unusual and external to the passenger who was disembarking in the usual manner: [42]-[43]

v) The passenger discharged the onus of proof even if the precise details and character of the external event were not proved: [50].

Sackville AJA concurring (with whom Allsop P and Ipp JA agreed): i) The event was external to the passenger since he was not responsible for the provision or placement of the step and the passenger did not act in a manner that caused the step to give way: [108].

ii) The portable step was not inert or operating as intended if it shifts when a passenger puts his or her weight on the step: [117]-[119].

iii) It is not necessary for a passenger to succeed in a claim for them to show that the event causing injury occurred independently of anything done or omitted by the passengers: [120].

iv) It is not necessary for a passenger to succeed in a claim for them to establish the reason why the aircraft or airline's equipment or services did not operate in the usual manner: [121].

The primary judge did not err in the awarding of general damages or damages for loss of economic capacity.

Allsop P and Ipp JA (Sackville AJA agreeing): i) The primary judge correctly dealt with the expert evidence in coming to the conclusion that general damages should be awarded: [77]-[79].

ii) The primary judge correctly applied the rule in Watts v Rake : [80]-[81].

iii) There was evidence capable of supporting the finding of loss of economic capacity: [94]

IN THE SUPREME COURT OF NEW SOUTH WALES COURT OF APPEAL 40407/08

ALLSOP P IPP JA SACKVILLE AJA

Thursday 20 August 2009 AIR LINK PTY LTD v PATERSON Judgment 1 ALLSOP P and IPP JA: On 25 September 1998, Mr Paterson (the plaintiff in the District Court and the respondent on the appeal) fell at Dubbo airport while disembarking from a small passenger aeroplane operated by Airlink Pty Limited ("Air Link", the defendant below and the appellant on the appeal). He was awarded damages of $439,500. For the reasons expressed below, we would dismiss the appeal. 2 Mr Paterson's claim against Air Link for the damages said to have been suffered by him was brought under the Civil Aviation (Carriers' Liability) Act 1959 (Cth) (the "Act"), s 28. The resolution of the controversy was, and is, in the exercise by the District Court, and by this Court, of federal jurisdiction: the Judiciary Act 1903 (Cth), s 39(2), as a matter arising under a law of the Parliament: the Australian Constitution, s 76(ii). As such, the choice of laws governing the resolution of the dispute was determined by the Judiciary Act, ss 79 and 80. No issue arose for debate concerning these issues. In particular, it was common ground between the parties that the Civil Liability Act 2002 (NSW) was not engaged in the resolution of the controversy. That State Act could not, of course, apply of its own force as a law of New South Wales, a polity different to that whose authority was being exercised to resolve the dispute, that being the Commonwealth (albeit by State judges), but rather as a form of surrogate federal law "picked up" by the Judiciary Act s 79. See generally Agtrack (NT) Pty Ltd v Hatfield [2005] HCA 38; 223 CLR 251 at 257-258 [6]-[11], 260-263 [24]-[32] and 266-271 [45]-[63]. In any event, the dates of the events in question here (1998) were well before the passing of the Civil Liability Act. On the basis of the parties' agreement, the primary judge approached the question of damages solely by reference to the common law: [83] of the reasons. In the light of this, it is not appropriate to comment upon the question whether the Civil Liability Act would be picked up by s 79 in another case.

3 Section 28 of the Act provides as follows: "Subject to this Part, where this Part applies to the carriage of a passenger, the carrier is liable for damage sustained by reason of the death of the passenger or any personal injury suffered by the passenger resulting from an accident which took place on board the aircraft or in the course of any of the operations of embarking or disembarking." (emphasis added)

4 Section 28 is part of Part IV of the Act which deals with carriage of passengers by air in circumstances involving carriage to which the relevant international conventions do not apply. Section 27(1) states as follows in this respect: "(1) This Part applies to the carriage of a passenger where the passenger is or is to be carried in an aircraft being operated by the holder of an airline licence or a charter licence in the course of commercial transport operations, or in an aircraft being operated in the course of trade and commerce between Australia and another country, under a contract for the carriage of the passenger: (a) between a place in a State and a place in another State; (b) between a place in a Territory and a place in Australia outside that Territory; (c) between a place in a Territory and another place in that Territory; or (d) between a place in Australia and a place outside Australia; not being carriage to which the 1999 Montreal Convention, the Warsaw Convention, the Hague Protocol, the Montreal Protocol No. 4 or the Guadalajara Convention applies."

5 There was no dispute but that s 28 takes its form substantially from Art 17 of the Convention for the Unification of Certain Rules Relating to International Transportation by Air done at Warsaw on 12 October 1929 (the "Warsaw Convention"). As a provision of domestic law owing its form to the adoption by the Commonwealth Parliament of the terms of an international instrument, the approach to construction is one which requires a recognition of its international source: Gulf Air Company GSC v Fattouh [2008] NSWCA 225; 251 ALR 183 at 190-191 [24]-[27] and the cases there cited. 6 Article 17 of the Warsaw Convention (unamended) as it appears in Schedule 1 of the Act provides: "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." 7 Article 17 of the Warsaw Convention, as amended by the Hague Protocol of 1955 and the Montreal Protocol No 4 of 1975, and as appearing in Schedule 5 of the Act has the force of law in Australia in relation to international air travel covered by its terms: the Act, s 25K. The form of Art 17 in Schedule 5 is identical to that in Schedule 1. The High Court in Povey v Qantas Airways Limited [2005] HCA 33; 223 CLR 189 in the light of a number of appellate judicial decisions of other countries, in particular Air France v Saks 470 US 392 (1985), construed Art 17 in Schedule 5 and rejected the proposition that deep venous thrombosis ("DVT") was covered by Art 17, because, it was held, there was no event capable of characterisation as an "accident" that caused the damage so sustained. 8 Air Link submitted here that, in accordance with Povey and other cases interpreting Art 17 of the Warsaw Convention, the primary judge erred in his conclusion that any injury of Mr Paterson was suffered by him as a result of an accident. 9 It is to be noted that there is some textual variation between s 28 and Art 17. The parties noted this fact in their submissions, but did not contend that any such textual difference led to any variation in relevant substantive meaning: cf Kotsambasis v Singapore Airlines Ltd (1997) 42 NSWLR 110; and South Pacific Air Motive Pty Ltd v Magnus [1998] FCA 1107; 87 FCR 301. Indeed, Air Link submitted that the textual differences made no difference. Mr Paterson did not submit to the contrary. 10 To appreciate the debate that arises here by reference to s 28 and the word "accident" therein and the various cases, including Povey, that have discussed the meaning and application of the relevant provisions, some understanding of what occurred and of the findings of the primary judge is necessary. 11 Mr Paterson was born in 1948, being 50 when the events occurred. He was 182 cm tall, weighing 125 kg. On the day in question, Friday 25 September 1998, he was flying home to Queensland, from Cobar in New South Wales, where he had been working conducting a workshop and seminar on mine safety procedures. The first leg of his trip home was from Cobar to Dubbo, where he was to pick up a connecting flight to Sydney, and from there another to Queensland. The Cobar to Dubbo flight was undertaken in a Piper Navajo Chieftain aircraft operated by Air Link. When the plane landed, the connecting flight was on the tarmac. Mr Paterson was the first passenger to disembark. The rear exit of the plane had a set of steps which folded out, but which did not reach the ground. A ground attendant placed a lightweight aluminium step below the steps from the plane. The plaintiff, carrying a laptop computer slung over his shoulder and carrying a bag with clothes, put his foot on the aluminium step. The judge found that the step moved, though he could not conclude what the cause of that movement was: [79] of the reasons. Mr Paterson then fell forward on to all fours striking his knees on the tarmac. He got up, not apparently seriously injured. Later, however, he suffered considerable pain and disability in his left knee. 12 The essential question on liability was whether what happened involved an "accident" covered by the Act, s 28 and the Warsaw Convention, Art 17. The primary judge concluded that it was. Air Link said that it had not been proved on the evidence to be such.

"Accident" in the Act, s 28 and the Warsaw Convention, Art 17 13 In the seminal case of Air France v Saks a passenger had suffered deafness brought on by air pressure changes in the descent of an aircraft to land. The plane had not behaved in any unusual way. The opinion of the Court was delivered by O'Connor J. At 405 and 406 the following was stated: "We conclude that 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. … … But 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. … … We draw this line today only because the language of Articles 17 and 18 requires it, and not because of any desire to plunge into the 'Serbonian bog' that accompanies attempts to distinguish between causes that are accidents and injuries that are accidents. See Landress v Phoenix Mutual Life Ins Co 291 US at 499 (Cardozo J dissenting). 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. Until Article 17 of the Warsaw Convention is changed by the signatories, it cannot be stretched to impose carrier liability for injuries that are not caused by accidents." (emphasis added) 14 These well-known passages were preceded by a discussion (at 397-405) as to the background to, and travaux préparatoires of, the Warsaw Convention. Early in that discussion (at 398) the distinction was drawn between an accident (in the sense of an event) which caused an injury, on the one hand, and an accident which is an injury (that is, an accidental injury) on the other. Reference was made to the well-known passage from Lord Lindley's judgment in Fenton v J Thorley & Co Limited [1903] AC 443 at 453, to learned writing on the Warsaw Convention, the French legal meaning of "accident", the negotiating history of the treaty and French jurisprudence on the Warsaw Convention. O'Connor J noted at 404: "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." This view was then noted as consistent with existing United States lower court authority, O'Connor J noting at 404-405: "… These observations are in accord with American decisions which, while interpretating the term 'accident' broadly, Maugnie v Compagnie Nationale Air France , 549 F 2d, at 1259, nevertheless refuse to extend the term to cover routine travel procedures that produce an injury due to the peculiar internal condition of a passenger. See eg Abramson v Japan Airlines Co, 739 F 2d 130 (CA3 1984) (sitting in airline seat during normal flight which aggravated hernia not an 'accident') …, MacDonald v Air Canada , 439 F 2d 1402 (CA5 1971) (fainting while waiting in the terminal for one's baggage not shown to be caused by an 'accident'); Scherer v Pan American World Airways, Inc , 54 App Div 2d 636, 387 N.Y.S. 2d 580 (1976) (sitting in airline seat during normal flight which aggravated thrombophlebitis not an 'accident')." These passages in Saks prior to the relevant statements of principle at 405-406 reinforce the context of the externality being discussed: it was an externality of event (of an unusual, unexpected kind) as distinct from the internal bodily reaction to usual or expected procedures or environment. 15 Povey concerned a claim by a passenger who suffered DVT said to have been developed by him on a flight from Sydney to London via Bangkok and return from London to Sydney via Kuala Lumpur. The Court (Gleeson CJ, Gummow, Hayne and Heydon JJ in joint reasons, Kirby and Callinan JJ concurring, each writing separately, McHugh J dissenting) concluded that DVT was not covered by Art 17 as amended by the Hague and Montreal No 4 Protocols. Consistently with the approach to construction involving the use of considered foreign decisions to assist in uniformity and there being no argument that it was wrong, the joint reasons accepted Saks as stating relevant principles. 16 The debate before the High Court proceeded from the premise found in both parties' arguments described at 203 [28] of the joint reasons, as follows: "[28] The arguments advanced by the parties began from the premise that a passenger's injury is caused by an accident only if 'caused by an unexpected or unusual event or happening that is external to the passenger' [ Saks 470 US 392 at 405 (1985)]. Each side recognised that this definition may require what the Supreme Court of the United States in Saks … called flexible application, but each side's argument began from the words that have been quoted. Where the arguments diverged was at the point of identifying what is meant by 'an unexpected or unusual event or happening that is external to the passenger'."

17 At 204 [32] in the joint reasons, their Honours noted (as was noted in Saks) that whilst continental jurists had significant influence in the drafting of the Warsaw Convention the French legal meaning of the word "accident" differed little from its meaning in Great Britain, Germany or the United States. Their Honours then said at 204 [32]: "[32] … Both in French, and in Anglo-American legal discourse (and, we would add, so too in Australian legal discourse) 'accident' may be used to refer to the event of a person's injury or to the cause of injury. By contrast, 'accidental' is usually used to describe the cause of an injury rather than the event and is often used as an antonym to 'intentional'."

18 Their Honours continued at 204-205 [33]-[34]: "[33] In Art 17, 'accident' is used to refer to the event rather than the cause of injury [ Saks 470 US 392 at 400 (1985)]. And that event is one which Art 17 requires to be located at a place (on board the aircraft) or otherwise to be fixed by reference to circumstances of time and place (in the course of any of the operations of embarking or disembarking). [34] Further, in understanding what is meant by 'accident', it is necessary to give proper weight to the way in which Art 17 relates three different concepts. Article 17 refers to 'damage', to 'the death or wounding of a passenger or any other bodily injury suffered by a passenger', and to 'the accident which caused the damage so sustained'. The damage sustained is treated as being distinct from the accident which caused the damage, and both the accident and the damage are treated as distinct from the death, wounding or other personal injury. What that reveals is that the 'accident', in the sense of 'an unfortunate event, a disaster, a mishap' [ The Oxford English Dictionary , 2nd ed (1989), vol 1 at 74, 'accident' meaning I, 1c] is not to be read as being sufficiently described as an adverse physiological consequence which the passenger has suffered. It may be accepted that its happening was not intended. In that sense, what is alleged to have happened may be described as 'accidental'. But suffering DVT is not an accident. Rather, as the parties to this appeal accepted, 'accident' is a reference to something external to the passenger." 19 At this point, it is important to appreciate the context of the last sentence in [34]. The required externality was enunciated in the context of a debate about the "bodily injury suffered" or the "damage sustained" being, or being referable to, a bodily or physiological response to the environment on the aircraft as it operated in the ordinary course. The same context existed in Saks. 20 The joint reasons continued at 205 [35]-[36]: "[35] It may also be accepted that an 'accident' may happen because of some act or series of acts, or because of some omission or series of omissions; it may happen because of some combination of acts and omissions. If that were not already clear, the reference in Art 25 to damage resulting from 'an act or omission of the carrier, his servants or agents' would point in that direction. It by no means follows, however, that asking whether an event was brought about by an act or omission and then classifying the act or omission as 'accidental' as distinct from 'intentional' is the same as asking whether there has been an 'accident' on board an aircraft. In particular, recognising the difficulties in seeking to classify causes of an accident as acts or omissions, or as intended or unintended acts or omissions, does not deny the need, under Art 17, to identify that an accident has occurred on board or in the course of the operations of embarking or disembarking. No other provision of Montreal No 4 suggests any contrary construction of Art 17. [36] No doubt as Saks indicates [(470 US 392 at 405 (1985)], the concept of 'accident' is not to be overrefined. It is a concept which invites two questions: first, what happened on board (or during embarking or disembarking) that caused the injury of which complaint is made, and secondly, was what happened unusual or unexpected? And as already pointed out, showing only that while on board or in the course of embarking or disembarking a passenger sustained some adverse physiological change does not identify the occurrence of an accident."

21 Their Honours then proceeded to discuss Olympic Airways v Husain 540 US 644 (2004), in which there was a sharp division in the United States Supreme Court as to the application of Saks to the facts involving the case of the death of an asthmatic passenger placed too close to the smoking section whose complaints and requests to move to another seat further away from the smoke had been either ignored or rejected by the cabin staff. After discussing the contents in this case, their Honours said at 206 [39]: "[39] These different formulations of the question that arose in Husain reveal at least two things. First, unsurprisingly, each sought to emphasise particular aspects of the circumstances surrounding the passenger's death. Secondly, each sought to identify whether something unusual or unexpected had happened on board the aircraft. The United States, as amicus, emphasised the response, or lack of response, to a medical emergency. The respondents emphasised the flight attendant's refusal to move the passenger. The airline sought to say, in effect, that nothing had happened on board that was unusual or unexpected; even if the flight attendant did not react as she should have reacted, there was no accident."

22 In Husain the majority concluded that there had been an accident on board the flight and the passenger recovered damages. 23 The joint reasons in Povey then (at 206-207 [40]-[43]), emphasised that it was central to the passenger's case in Povey that nothing happened on board that was out of the ordinary in any way, nor were flight conditions unusual or unexpected. The case was one of a failure to warn of a hazard from long haul flying in otherwise standard conditions. This failure was not an "accident" on board the aircraft. In stating that assertions of "failure" to act were unhelpful in the enquiry, their Honours said at 207 [42]: "[42] … Further, reference to failure is unhelpful because it diverts attention from what it is that happened on board to what might have, could have, or perhaps should have happened there and why that should be so. If, as earlier indicated, it is appropriate to ask 'what happened on board?' the answer in this case is that the appellant alleges that nothing unexpected or unusual happened there."

24 Their Honours found support for their conclusion of no accident in what the English Court of Appeal had said in In re Deep Vein Thrombosis and Air Travel Group Litigation [2003] EWCA Civ 1005; [2004] QB 234. Their Honours said at 207-208 [44]: "[44] … In Re Deep Vein Thrombosis Litigation [[2004] QB 234], the Court of Appeal of England and Wales held that the word 'accident' in the Warsaw Convention as modified by the Hague Protocol was to be given a natural and sensible, but flexible and purposive meaning in its context [[2004] QB 234 at 244 [9], 245 [15], 246 [20]] and that for there to be an accident within the meaning of the relevant article, there had to be an event external to the passenger which impacted on the body in a manner which caused death or bodily injury and the event had to be unusual, unexpected or untoward [[2004] QB 234 at 246-249 [19]-[38]]. The Court held [[2004] QB 234 at 248 [29]] that inaction was a non-event which could not properly be described as an accident. Not warning of the risk of DVT and not giving advice on the precautions that would minimise that risk were not events [[2004] QB 234 at 248 [29]]. The conditions in which passengers travelled on flights (with cramped seating and the like) were not capable of amounting to an event that satisfied the first limb of the definition of an accident which 'took place on board the aircraft or in the course of any of the operations of embarking or disembarking' [[2004] QB 234 at 248 [28]]."

25 Once again, it is to be emphasised that the externality referred to was in the context of a debate as to whether the bodily response to the ordinary or usual aircraft environment involved "an accident". The passages referred to from the Court of Appeal relied on Saks in this context: see [2004] QB 234 at 244 [9], 245 [15] and 246 [20] and 246-249 [19]-[38] (per Lord Phillips of Worth Matravers MR). 26 Kirby J, in his concurring judgment in Povey, recognised (at 236-237 [153]) that the decision in Saks demanded three elements: "[153] …These are (1) a cause separate from the 'injury' itself; (2) an 'event or happening' that is unexpected or unusual; and (3) an event that is external to the passenger." 27 In dealing with the third element, Kirby J recognised that it was part of the definition necessary for the resolution of the factual dispute in Saks, involving a "pathological event that occurred internally to the passenger, Ms Saks": at 238 [160].

28 In 2005, after Povey, the DVT Litigation case in England was decided by the House of Lords: In re Deep Vein Thrombosis and Air Travel Group Litigation [2005] UKHL 72; [2006] 1 AC 495. The House of Lords reached the same result as in Povey and had recourse to the reasoning in Povey: Lord Scott of Foscote at 505-506 [20]-[24], Lord Steyn at 509-510 [39]-[42], Lord Walker of Gestingthorpe (agreeing with both Lords Scott and Steyn). Baroness Hale of Richmond also agreed, but she made some further comments. Lord Mance concurred. While agreeing with Lords Scott and Steyn, his Lordship gave his own substantive reasons, which also employed the reasoning in Saks and Povey. It is unnecessary to analyse the reasoning in their Lordships' speeches, but two passages in the speech of Baroness Hale and Lord Mance should be noted in order to appreciate the reasons of Laws LJ in the next case, Barclay v British Airways Plc [2008] EWCA Civ 1419; [2009] 1 All ER 871. Baroness Hale said at 511-512 [49]: "[49] … Once it is clear that the accident which causes the injury must be something other than the injury itself, it becomes equally clear that the suffering of an internal reaction to an ordinarily uncomfortable journey by air, during which nothing untoward other than that reaction took place, cannot fall within article 17 of the Warsaw Convention. But I would particularly like to associate myself with the observations of my noble and learned friend, Lord Scott of Foscote, on the dangers of interpreting the words of the decision of a court, which is interpreting the words of the Convention, as if the court's words were those of the Convention. If I fall over during a flight to New York, and break an arm, I suspect that we would all agree that my broken arm was caused by the accident of my fall; and we would do so irrespective of the reason for my fall; if it was my own silly fault, article 21 may relieve the airline of some or all the liability imposed by article 17, but that is another matter. In reaching those conclusions, we should not be agonising too much over whether my fall was an event 'external' to me. We should simply be asking whether it was an 'accident' which led to my injury. My own synonym for 'accident' would be 'untoward event' but that is by the way."

29 Lord Mance on the other hand said at 515 [56]: "[56] … Death from entirely natural or internal causes may be described as accidental, but it is not caused by an accident, which is what matters under article 17; and, if a passenger were to suffer bodily injury as a result of a fall on board which was due to some internal condition (such as partial paralysis or drunkenness) not sensibly attributable to the airline, it seems improbable that his injury should be regarded as caused by a relevant accident: compare Chaudhari v British Airways plc The Times, 7 May 1997; Court of Appeal (Civil Division) Transcript No 590 of 1997 - although in that case there were allegations of negligence on the airline's part, which would, it may be, lead Mr Scrivener to submit that the court should have taken a different view on the facts - and Padilla v Olympic Airways (1991) 765 F Supp 835." This passage appears to contemplate that an unintended event such as a fall would not be an accident if it originated from an internal condition or characteristic of the passenger. Baroness Hale, on the other hand, can be seen to advocate a less refined analysis of "accident" by asking whether an unexpected event occurred. 30 In Barclay, the passenger slipped on a plastic strip running under the seats covering the seat fix tracking. After slipping, her knee gave way, struck the armrest causing her to sustain injury. The strip was a standard fitting and the aircraft was in normal working order complying with all relevant regulations. The passenger's claim failed. The Court of Appeal (Laws LJ giving the leading judgment, Thomas LJ and Wilson LJ concurring) said there was no accident within the meaning of Art 17 of the Warsaw Convention. Laws LJ in (if we may respectfully say so) a careful and reasoned judgment discussed, the balance of the interests in the Warsaw Convention as elaborated upon in the jurisprudence, the notion of the word "accident" in English cases including in particular the House of Lords in In re Deep Vein Thrombosis and Air Travel Group Litigation and the Supreme Court in Saks. Laws LJ referred to the comments of Baroness Hale to which I have referred as "problematic": at 882 [28]. After dealing with the arguments, his Lordship said at 884-885 [35]: "[35] I conclude that art 17(1) contemplates, by the term 'accident', a distinct event, not being any part of the usual, normal and expected operation of the aircraft, which happens independently of anything done or omitted by the passenger. This gives the term a reasonable scope which sits easily in the balance the convention strikes. It is, I conceive, in line with all the leading authorities from Air France v Saks onwards which, save only, with respect, for Lady Hale's opinion in Re Deep Vein Thrombosis and Air Travel Group Litigation , uniformly emphasise the importance of the causative event's being 'external' to the passenger. There are some particular formulations in the cases which (without picking over the texts to the last comma, a fruitless and inappropriate exercise) especially point, as it seems to me, towards this approach. I have already cited Lord Phillips MR's judgment in Re Deep Vein Thrombosis and Air Travel Group Litigation [2006] 1 All ER 786 at [21], where he referred to 'an untoward event which impacts on the body'. This suggests to my mind the happening of an event which is anterior to and separate from any involvement of the passenger. So also Lord Steyn's observation (at [33]) that '[i]t is an integral part of the test of what amounts to an accident that it must have a cause external to the passenger'. Assistance is also to be had from O'Connor J's observation at 406 of Air France v Saks itself: '[W]hen 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.' This was the passage which, it may be recalled, Mr Menzies submitted was 'not part of the Saks definition'. I do not agree. This statement is part and parcel of the Supreme Court's exegesis of the convention." (emphasis added) 31 Not surprisingly in this case, Air Link emphasised and relied upon the reasoning of Laws LJ in Barclay. It was accepted by Air Link, however, that the externality required by Laws LJ did not exclude from the definition of accident an event which involved the participation of the passenger, in some sense, as long as the event was unusual, abnormal, or unexpected in that it had been caused otherwise than by the passenger, that is externally. 32 Turning to the case here, Air Link submitted that Mr Paterson had not proved that any relevant event was unexpected or abnormal or unusual because it had not been proved what caused the lightweight aluminium step to move. Air Link emphasised that Mr Paterson was a big man, approximately 40 kgs in excess of the healthy weight range for his height, that he had a history of left knee restriction, that on alighting from the aircraft he was carrying at least two pieces of luggage, that he had difficulty getting through the doorway of the aircraft as he attempted to leave the aircraft, that there was some urgency in his alighting from the aircraft to meet his connection, that the step from aircraft steps to the portable step was awkward, that the other passengers from the aircraft alighted successfully using the step, that there was no evidence that the step was damaged or defective in any way and that it had not been proven that the step was resting on the surface in an unstable way. 33 Thus, Air Link submitted that because the cause of the step moving had not been proved Mr Paterson must necessarily fail. It was also submitted on the appeal (although the notice of appeal had not made this plain) that Air Link challenged some relevant findings of fact by the primary judge. 34 It is therefore necessary to turn to the reasons of the primary judge to understand what he did find about the events in question and the evidential context of those findings. 35 In his Honour's reasons at [76]-[82] the primary judge dealt with the facts of the fall. He referred to parts of the evidence of Dr Olsen (a consultant physician in occupational and environmental medicine, whose report was tendered by Mr Paterson) as indicative of a problem in the step: [76] of his reasons. He referred to a letter sent by Mr Paterson's solicitor's not long after the accident in November 1998 which included allegations on Mr Paterson's instructions that: "The stairs in questions were inherently unsafe … when, according to our instructions the stairs were placed on uneven ground thus resulting in one of the legs (of which there were four) not resting on the ground. As our client stepped on to the staircase, it gave way from underneath him thereby causing our client to fall to the ground." 36 The primary judge also referred to the history given to Dr Olsen by Mr Paterson when the matter was fresh in his mind. The primary judge referred to the evidence of a Mr Molina who was present at the time. Mr Molina said that he did not see what caused the step to flip but he said it went rolling over a distance up to a metre. The primary judge commented (at [79]) that "[s]omething obviously caused the step to behave as it did." The primary judge then expressed the view that he thought Mr Molina's recollection of the plaintiff stating immediately afterwards that the step was unsafe was important. 37 At this point, it is helpful to set out what Mr Paterson said in his oral evidence, bearing in mind that the primary judge accepted the evidence of Mr Paterson. In chief, Mr Paterson said the following: "Q. You saw that [the lightweight step] being put into position by an attendant. Is that so? A. I saw it come out but I didn't see it being put in position and I stepped down. Q. As you stepped down from the plane on the steps inside the door did you notice the portable step in position? A. Yes. Q. Did you pay any particular attention to exactly where it was by way of alignment with the other steps and how far below the bottom one it was? A. I didn't take any particular notice. By exception I just assumed it was the same as always. Q. There are only a couple of steps down inside the door before you stepped off to put your foot on that portable step. Is that right? A. That's correct. Q. Can you remember which was your leading foot as you stepped onto the portable step? A. I can't remember. Q. You have told us you were holding your laptop bag. How did you have hold of that? A. I would have had it over my shoulder and clutching it to my side. Q. Do you recall putting your foot on the portable step? A. I remember touching the - putting my foot onto the step and next finding myself on the ground. Q. Do you remember the transfer of your weight, your weight going onto the step? If you don't remember this detail just say so. A. Not really. I don't remember that part. It happened so quickly. Q. Do you remember any particular movement of the step? Do you remember it moving? A. Yes, the step moved. Q. In what way do you remember it moving? A. It flipped from underneath me. Q. What happened to you then? A. I went down onto the ground and landed on all four trying to protect my back." 38 From that evidence, it can be accepted that Mr Paterson did not jump on to the step nor do anything unusual. It is not clear where precisely on the step he stood, whether in the middle of the step or towards the edge of the step. Nevertheless, he put his foot on the step and placed weight on it in a manner which reflected his alighting from the plane in what might be said to be a usual way. 39 It was in this context that the primary judge said the following at [79]-[80]: "[79] … Something obviously caused the step to move. I cannot, on the evidence, conclude what that cause was. I think I can conclude, however, that whatever it was constituted an unusual or unexpected event. As stated by Korman J in [ Girard v American Airlines Inc [2003 US Dist Lexis 14506]: ' It is not usual or expected that the stairs of a terminal bus would abruptly give way, nor would an injury incurred by such a defeat be within the normal operation of an aircraft or airline'. True it is that there is no direct evidence of a defect in the step (as given by the plaintiff's daughter in Girard ) but there is also no evidence that the step gave way because of some act on the part of the plaintiff. Adopting the words in Saks at 406 the plaintiff's injury ws not a result of his own ' internal reaction to the usual, normal, and expected operation of the aircraft'. [80] Taken with the plaintiff's statement to the pilot (Mr Kelly), the contents of the letter from his solicitors in November 1998, his own description of the step giving way and the effect of it giving way as described by Mr Molina, in my view I can conclude that the step gave way as a result of an external factor. I think this conclusion can be reached without even adopting a 'liberal' approach and even though I could not say the step gave way because of an uneven surface or a[n] incline on the ground. As to Dr Olsen's report I make no more use of it than to say that my conclusion is consistent with his opinion." (emphasis added)

40 The two sentences which are emboldened in [79] and [80] are factual findings made by the primary judge which were challenged in argument. 41 In the light, however, of the evidence of Mr Paterson, which was accepted, it can be concluded that his Honour's findings were that while the precise cause of the movement of the step could not be identified, it was as a result of an external factor. In this context, the reference to "the step gave way" in [80] can be understood as a finding that the step moved as his Honour found in [79]. 42 On the evidence, these findings were plainly open and in our view correct. There was an event: the sudden movement of the step. That sudden movement of the step was physically external to the passenger. That sudden movement of the step was unexpected and abnormal. In our view there was plainly an accident within the meaning of Art 17. It was submitted on behalf of Air Link that the sudden movement of the step of this kind could be normal depending upon the responsibility of the passenger for the event. It was submitted, with a large somewhat overweight passenger who might have stepped on the edge of the step, the event could then be seen to be expected by reason of the likely behaviour of the lightweight step if someone trod on the edge rather than the middle of the step. Thus, it was submitted, one needed to understand the cause of the event with precision. 43 In our view this is an overrefined and artificial approach. There was an unusual and unexpected event. On the evidence of the plaintiff, which was accepted, the primary judge's findings in this regard were correct. Likewise, his findings that the step gave way as a result of an external factor can be accepted as correct. There was an unexpected and unusual event or happening external to Mr Paterson which caused his fall. There was, therefore, applying Povey at 203-208 [28]-[44], an accident. 44 In these circumstances, it is unnecessary to discuss any further the correctness or applicability of Barclay. We would reserve our position on the correctness of the approach in [35] of Laws LJ's reasons and whether or not it is a proper application of what was said in Saks and Povey and a correct understanding of Art 17 of the Warsaw Convention.

45 It should also be said that there are a number of United States' cases which restrict the meaning of "accident" in Art 17 to events not only that are external to the passenger and unusual or unexpected but also that involve a malfunction or abnormality in the aircraft's operation: Gotz v Delta Air Lines Inc 12 F Supp 2d 199 (1998 D. Mass) (shoulder injury from hyperextension while holding a bag overhead to avoid another passenger who stood up not an accident); Garcia Ramos v Transmeridian Airlines 385 F Supp 2d 137 (2005 D. Puerto Rico) (one passenger injured when another passenger fell on him during boarding not an accident); Sethy v Malev Hungarian Airlines Inc 2000 US Dist Lexis 12606 (passenger tripped over luggage in aisle not an accident) (affirmed by summary order by the Second Circuit Court of Appeals on 12 June 2001); Sharma v Virgin Atlantic Airways 2006 US Dist Lexis 20127 (passenger slipping on a soapy toilet floor that proper procedures should have seen attended to by flight attendants an accident). 46 Multiplication of examples is not necessarily helpful. It suffices to say however, that the notion of externality and the usual operation of the aircraft have been welded by the courts in some of these cases into a construction that can exclude some undoubted accidents as external events on board aircraft because the events, which in a sense were external to the passenger, did not involve the malfunction of some aspect of the aircraft's equipment or of appropriate systems. There must be at least some doubt that these cases involve judicial glosses on the words of the article that do not find their source in the words of Art 17 itself, or, indeed, in the words of O'Connor J in Saks. 47 For the reasons we have otherwise given, these questions need not be decided in this case.

48 Here, an unexpected and unusual external event was present. There was an accident within the meaning of the Act, s 28. 49 We should add that our reasons do not require the adoption of Baroness Hale's comments to which we have referred. Nor, on our reading of the primary judge's reasons, did the adoption of Baroness Hale's views play an essential part in the reasoning of the primary judge. 50 In our view, Mr Paterson discharged the onus of proof in showing that the event which caused him to fall was one which was unusual, unexpected and externally caused, even if the precise details and character of that external cause were not proved. In our view, the primary judge's factual findings were soundly based and his conclusion that there was an accident for the purposes of the Act, s 28 was sound. 51 The above reasons deal with the arguments, as we understood them, put forward by Air Link. In particular, in this respect, we refer to the second sentence of [31] above, which we took to be a less than completely literal reliance upon [35] of Sir John Laws' reasons in Barclay. 52 Since completing these reasons in draft we have had the advantage of reading the reasons in draft of Sackville AJA, which deal with Air Link's arguments on the assumption that it does rely on the literal text of [35] in Barclay. To the extent that Sackville AJA is correct in appreciating the scope of Air Link's arguments, we adopt his Honour's reasons in dealing with [35] of Barclay. As his Honour says, [35] of Barclay, if read literally, goes beyond what is said in Povey as to the meaning of "accident". To that extent we are, of course, bound by the High Court, irrespective of what other considered decisions of foreign courts would say. We also otherwise agree with the reasons of Sackville AJA.

Damages 53 The primary judge awarded the respondent damages of $439,500. This amount was made up as follows:

General damages $ 50,000 Interest on general damages $ 20,000 Economic loss $250,000 Interest on economic loss $115,000 Out of pocket expenses $ 4,500 TOTAL $439,500

54 The appellant challenges his Honour's assessments of general damages of $50,000 and economic loss of $250,000 (and, in consequence, the interest payable on these amounts).

General damages of $50,000 55 In March 1997 Mr Paterson experienced pain in his left leg. He was admitted to hospital with the complaint of "left knee injury". The history Mr Paterson gave to the hospital included a complaint of a swollen and painful left knee that had endured for two months. The hospital diagnosis included "medial meniscal injury". A report of an x-ray taken at hospital indicated that "a small volume joint effusion was present, with marginal looping at the articular surface of the patella". All the medical experts in the case agreed that the x-ray report in question indicated signs of minor degenerative change. 56 At trial Mr Paterson acknowledged his pre-existing condition but contended that it was nothing more than a mild inconvenience that did not require him to change his work habits. 57 Mr Paterson is a qualified engineer and his business prior to his fall on 25 September 1998 was that of "asset management and maintenance". As part of that business he would, as a consultant, visit mining sites and similar locations where he would inspect machinery and report on the standard of maintenance being applied. He was required to climb up and down ladders and, generally, to be physically active. His pre-existing condition did not preclude him from undertaking this work. 58 After the fall, Mr Paterson's left knee swelled up and progressively worsened. He could only walk by hobbling and he could not bend the joint. 59 In November 1998, Mr Paterson consulted Dr Ohmsen, a sports physician, who found mild effusion in the left knee and medial joint line tenderness consistent with an acute tear of the medial meniscus. Dr Ohmsen advised Mr Paterson to have an arthroscopy to assess the meniscus. Mr Paterson, however, had a strong aversion to being anaesthetised and did not have an arthroscopy until 2007. In the interim, he continued to have problems with his knee. He found travelling "very challenging" and had difficulties with the on-site visits that his work required. This caused him to change his business from asset management and maintenance to project management, which was more sedentary. 60 In February 2007 an x-ray revealed degenerative changes involving both knees which were "moderately severe in the right patellofemoral compartment". 61 On 1 March 2007, an arthroscopy was performed on the left knee. There was eburnated bone at the patella and trochlea and a probably symptomatic complex tear of the postero medial portion of the medial meniscus. By the arthroscopy, the tear was repaired and other remedial treatment was carried out. 62 Mr Paterson, for a while, obtained significant benefit from the arthroscopy but soon afterwards began to have problems with his right knee. He contended that, as a result of him favouring his left knee, extra pressure was put on the right knee, which was injured in consequence. Mr Paterson had not pleaded an injury to his right knee but the trial appears to have been run on the basis that he was entitled to claim damages for an injury to that knee and no point was made of this on appeal. 63 In summary, at trial, Mr Paterson's case was that the fall on 25 September 1998 caused:

(b) The pre-existing condition in the left knee to be aggravated. (c) The aggravated condition in the left knee to continue until after the arthroscopy (to a significantly worse degree than would have been the case had the fall not occurred).

(d) The right knee to be injured. 64 Air Link's case, on the other hand, was that:

(a) The meniscus had been torn before the fall. (b) While the fall had exacerbated the pre-existing condition in the left knee, that exacerbation only lasted a few months. (c) Within a few months after the fall, the exacerbation to Mr Paterson's left knee injury ceased (in other words, by then he had recovered from any injury caused by the fall). (d) Any disability from which he suffered thereafter (to both knees) was caused by his pre-existing condition.

65 Both parties led expert evidence to support their respective cases. The primary judge, however, was unable to decide which of the competing views expressed by the parties' respective experts was correct. His Honour said at [53]: "[53] In my view, every one of the doctors could be right and none of the views are such that they could be accepted as a probability over the others. If I approach it on a numerical basis then Mr Paterson would win (three to one) but I specifically do not do so. I thought Dr Coolican [called by Air Link] was as persuasive as Dr Wallace, Dr Pentis and Dr Ohmsen [called by Mr Paterson]." Thus, his Honour found Mr Paterson had not proved that the fall caused the meniscus to tear. 66 Nevertheless, his Honour found that Mr Paterson had proved that he had aggravated the previous existing injury to his left knee and that the symptoms of pain, discomfort and disability that he suffered as a result of that exacerbation continued until he recovered from his arthroscopy in 2007. 67 This finding was based on two categories of findings. Firstly, his Honour accepted Mr Paterson's evidence that: (a) Prior to the fall he worked and developed his asset management and maintenance business without any interference from his left knee. (b) After the fall his left knee began to swell and progressively became worse until he was hobbling and could not bend the joint. (c) He continued to suffer pain, over and above that from which he suffered prior to the fall, until after the arthroscopy in 2007. (d) "[F]ollowing the fall his left knee progressively became worse and although it fluctuated in time the problems were such that as a result of them, he made a deliberate change to the manner of conducting his business": see [61] of the reasons.

Secondly, his Honour held that it was "clearly" open to him, on the medical evidence, to find that "the degenerative process, and the pain and restriction in the knee, could have been aggravated by the fall and that that aggravation could have continued for some time": see [49] of the reasons. 68 Based on these findings his Honour accepted (at [84]) that: "[84] … [T]here was a significant increase in pain and restriction of movement which progressively became worse following the fall and that this extra pain and limitation continued, as far as the left knee is concerned, for some years and probably up to the arthroscopy in 2007." 69 The primary judge further found that the condition of Mr Paterson's knee was such that the degeneration would ultimately have brought about a need for treatment, and perhaps an arthroscopy, but these consequences would have occurred later than when they in fact occurred. 70 The primary judge took the injuries to the right knee into account as a factor in the assessment of general damages "on the basis that it may, to some degree, have been caused by the left knee problems or at least its condition accelerated by the favouring of the left leg" see [84] of the reasons. 71 On the basis of these findings, his Honour assessed general damages at $50,000. 72 In challenging the primary judge's assessment of this head of damages, Air Link relied on three grounds of appeal, namely: (a) His Honour failed to deal with the evidence relating to the cause of the "knee disability". (b) His Honour erred in determining Mr Paterson's injuries by reference to his evidence as to the effect on him of the injuries that he suffered. (c) His Honour erred in failing to determine the nature and extent of Mr Paterson's injuries by reference to the expert evidence. 73 Mr R Williams QC, who together with Mr Stanton appeared for Air Link, submitted that Mr Paterson never fully recovered (as he admitted) from the condition that had been detected in March 1997. He repeated that, at that time, Mr Paterson was almost 49 years old and, although his ideal weight for height was 85 kg, between early 1997 and July 1998 he was at least 40 kg above that weight. In November 1998, Mr Paterson advised his doctor that he was improving and did not seek any further treatment until 2007. Mr Williams submitted that the primary judge should have found that the fall caused a temporary exacerbation of the pre-existing injury for a few months, but thereafter what occurred was inevitable because of that pre-existing injury. 74 Mr Williams drew attention to the fact that orthopaedic surgeons on each side offered their views as to whether the meniscus had been torn by the fall and as to whether the symptoms the respondent experienced over the relevant period were caused significantly by the fall or would have been experienced in any event because of Mr Paterson's pre-existing condition. Mr Williams submitted: "The judge elected not to determine the issue by reference to the medical evidence but to what [Mr Paterson] said about it". He argued that his Honour was not entitled to resolve the issue "of what impact the fall had on [Mr Paterson's knee]" by simply basing his finding on Mr Paterson's evidence (which, according to Mr Williams is what his Honour did). 75 In Zurich Australian Insurance Ltd v Raman; Gyimah v Mackay [2009] NSWCA 221, the reliability of lay witnesses in large measure depended upon how differences between experts were resolved. These differences were capable of being resolved rationally by examination and analysis and the trial judge made no demeanour findings in regard to the experts. The judge, nevertheless, decided the matter on the basis of demeanour, not of the experts themselves, but of the lay witnesses. His Honour resolved the difference between the experts, without any rational analysis of their opinions, but by preferring the opinion that was consistent with his credibility findings concerning the disputed evidence of lay witnesses. His approach was held to be erroneous. 76 The circumstances of this case, however, are entirely different. Firstly, the credibility of Mr Paterson's testimony was not dependent on which expert opinion was to be preferred. It was common ground that he had a pre-existing condition. Secondly, his Honour did subject the use of the expert witnesses to rational analysis and also took into account their demeanour, as he was entitled to do (Wiki v Atlantis Relocations (NSW) Pty Ltd [2004] NSWCA 174; 60 NSWLR 127). His Honour referred to and examined hospital notes, a note by Dr Yelland, (Mr Paterson's general practitioner), the notes of Dr Ohmsen, an MRI report, extracts of the evidence of Drs Wallace and Pentis (orthopaedic specialists called by Mr Paterson), the report of Dr Millons (a specialist whose report was commissioned by Air Link but tendered by Mr Paterson) and the evidence of Dr Coolican (an orthopaedic specialist called by Air Link). 77 Having conducted what amounted to an appropriate review of the testimony, the primary judge concluded that Mr Paterson had not proved that the fall caused the tear in the meniscus. As regards the degree and duration of the exacerbation that had occurred, his Honour was unable to decide which of the views of the experts was to be preferred. It was implicit, however, in his Honour's reasons that he accepted that, on the evidence, there was a reasonable possibility that the "degenerative process, and the pain and restriction in the knee, could have been aggravated by the fall and that that aggravation could have continued for some time": see [49] of the reasons. This inference is to be drawn from his Honour's observation (also at [49]) that it was "clearly open" to him to make such a finding. 78 In Sydney South West Area Health Service v Stamoulis [2009] NSWCA 153, Ipp JA (with the agreement of Beazley and Giles JJA) after referring to Seltsam Pty Ltd v McGuiness [2000] NSWCA 29; 49 NSWLR 262 (at 276 [89], 278 [98] and 287 [153]), EMI Australia Ltd v BES [1970] 2 NSWR 238 (at 242) and Fernandez v Tubemakers of Australia Ltd [1975] 2 NSWLR 190 (at 239, 240), said at [138]: "The fact that experts do not infer causation on a balance of probabilities does not mean that a court may not: Seltsam v McGuiness at [143]-[144]. A finding of causal connection may be made even when the expert evidence does not rise above the possible; the question is always whether the evidence as a whole establishes causation on a balance of probabilities: Seltsam v McGuiness at [89], [94]-[96], [98]-[100], [102], [143], [144] and [155]." 79 His Honour's findings as to the degree and the length of the period of exacerbation were made on entirely orthodox principles. Ordinarily, it is necessary for a trial judge to attempt to resolve differences between expert witnesses, particularly when that can be done by rational analysis. In this case, the primary judge explained, carefully, why he was unable to do so. That finding was open. We would not accept Air Link's criticism of the way in which his Honour dealt with the expert testimony. 80 Another way to approach the issue of the expert testimony is to analyse the situation by reference to the rule in Watts v Rake [1960] HCA 58; 108 CLR 158 as explained in Purkess v Crittenden [1965] HCA 34; 114 CLR 164. That rule (as expressed in Purkess v Crittenden (at 168) per Barwick CJ, Kitto and Taylor JJ) is as follows: "[W]here a plaintiff has, by direct or circumstantial evidence, made out a prima facie case that incapacity has resulted from the defendant's negligence, the onus of adducing evidence that his incapacity is wholly or partly the result of some pre-existing condition or that incapacity, either total or partial, would, in any event, have resulted from a pre-existing condition, rests upon the defendant." 81 The rule in Watts v Rake only operates to place an evidential onus on a defendant when the plaintiff establishes that the defendant's negligence has, in fact, caused a change in the plaintiff's condition. This is what his Honour found in Mr Paterson's case (and it was not in contest). The evidential burden then shifted to Air Link to adduce evidence that Mr Paterson's incapacity was the result of his pre-existing condition or that that incapacity, either total or partial, would, in any event have resulted from the pre-existing condition. Air Link adduced evidence to this effect, but the primary judge found that, upon the whole of the evidence, Mr Paterson had satisfied him of the extent of the injuries caused by the fall. 82 Again, in our view, on this basis the reasoning of the primary judge was unexceptionable. Accordingly, we would dismiss the appeal against the assessment of general damages.

Economic Loss of $250,000 83 The primary judge assessed Mr Paterson's loss of economic capacity of $250,000 on the basis of his finding that the injuries caused by the fall endured until after the arthroscopy in March 2007. This finding was challenged but, for the reasons we have expressed when dealing with the general damages award of $50,000, that challenge fails. 84 His Honour found that Mr Paterson's injuries caused him to change his business from asset maintenance and management to project management and this change led to a loss of $250,000. Air Link contended that the evidence did not support the finding that a loss of $250,000 had been incurred. 85 At trial, Mr Paterson tendered two reports by Mr David Watt, an expert accountant. These reports were based, partly, on the actual income and expenses of the Mal Paterson Family Trust. The amounts of income and expenditure were derived from the financial statements of that Trust. 86 The Trust distributed its profits to Mr Paterson and certain family members but no point of this was made at the trial. The parties accepted that for all intents and purposes the trust was Mr Paterson. As is stated by Harold Luntz, Assessment of Damages for Personal Injury and Death, 4th ed (2002) at 5.5.6: "Under the principle recognised in Husher v Husher [1999] HCA 47; (1999) 197 CLR 138 plaintiffs who maintain control of the product of the exercise of their earning capacities, even if they have adopted some sort of company or trust structure to diminish the impact of taxation, should be able to recover the full value of their earning capacity and so indirectly recover also for losses sustained by other members of the company or beneficiaries of the trust that result from the diminution in the victim's ability for work." 87 Mr Paterson conducted his asset maintenance and management business until 1999 and a project management business thereafter. He testified that the asset maintenance and management business was more profitable than project management and that from 1999 - 2001 he was building up his business and "re-directing" himself and his financial opportunities: Black 34. 88 Consistently with that evidence, Mr Watt's first report demonstrated that for the years ended 30 June 1999 to 2004 the operating profit of the Trust was significantly less than that for the year ended 30 June 1998. The reductions in question were about $124,000 in 1999, $132,000 in 2000, $149,000 in 2001, $11,000 in 2002, $107,000 in 2003 and $97,000 in 2004: see Blue 80. The reduction in profits has to be seen in the context of the fact that, as Mr Paterson testified, there was a downturn in the mining industry from 1999 - 2001. 89 The relevance of the evidence referred to in the previous paragraph is that it is capable of supporting Mr Paterson's case that his injuries caused him loss of economic capacity. He testified that it was his forced change to the new project management business that caused the reduction in profits. 90 Mr Sexton SC, who together with Mr Regattieri appeared for Mr Paterson, drew attention to the following additional matters: (a) In Mr Watts first report, on the basis of actual figures derived from the financial statements of the Trust, he expressed the opinion that Mr Paterson's past economic loss (encompassing the period from the fall in 1998 to 2006) had been $376,000. (b) After Mr Paterson had served Mr Watt's first report, Air Link responded by serving a report from its expert, Mr Ivey. That report of Mr Ivey was not tendered but Mr Watt referred to it in his second report, which was tendered. Paragraph 8.4 of Mr Watt's second report stated "The Ivey Report concludes that [Mr Paterson's] past economic loss for the period from 25 September 1998 to 30 June 2002 amounts to $227,000 (after tax)". No objection was made at trial to the material in Mr Watt's second report concerning the Ivey Report. (c) In his second report Mr Watt expressed the opinion that Mr Paterson's economic loss was more than the amount at which Mr Watt arrived in his first report. 91 The primary judge found that there was "definitely" an economic loss (at [93]). His Honour, however, did not accept the loss as calculated by Mr Watt. 92 The primary judge accepted that, while not all of the losses derived from actual figures as set out in Mr Watt's first report were attributable to Mr Paterson's injuries, some significant losses were in fact caused thereby. In effect, in awarding $250,000 over the period in question of about eight years, his Honour allowed for losses, on average, of just over $31,000 per year as having been caused by Mr Paterson's injuries. As his Honour said (at [94]), the amount of $250,000 was "consistent with Mr Ivey's approach which produced a loss of $227,000". 93 His Honour undoubtedly applied a broad-brush approach. But, contrary to Air Link's submissions, there was evidence to support it. His Honour was doing the best he could, based on the evidence and his findings as to the nature of the injuries Mr Paterson suffered. In our view, he was entitled to adopt that approach and it is not correct to say that his finding was not based on the material in evidence before him. We would therefore dismiss the appeal against economic loss. 94 Accordingly, the appeal should be dismissed with costs. 95 SACKVILLE AJA: I agree with the orders proposed by Allsop P and Ipp JA and with their Honours' reasoning on the question of damages. 96 I also agree generally with their Honours' reasoning on the question of liability. However, I wish to express my own reasons for rejecting the argument advanced on behalf of the appellant, in particular the reliance placed on the observations of Laws LJ in Barclay v British Airways plc [2008] EWCA Civ 1419; [2009] 1 All ER 871, at [35]. The outcome of the appeal turns on the application of s 28 of the Civil Aviation (Carriers' Liability) Act 1959 (Cth) ("CA Act") to the facts of the present case. Section 28 reads as follows: "Subject to this Part, where this Part applies to the carriage of a passenger, the carrier is liable for damage sustained by reason of the death of the passenger or any personal injury suffered by the passenger resulting from an accident which took place on board the aircraft or in the course of any of the operations of embarking or disembarking."

The Legislation and The Convention 97 The Warsaw Convention as amended at the Hague Convention, 1955, and by Protocol No 4 of Montreal, 1975 ("Convention") applies to the international carriage of persons, baggage or goods (Art 1(1)). Section 25K(1) of the CA Act provides that subject to Part IIIC, the Convention: "has the force of law in Australia in relation to any carriage by air to which the [ Convention ] applies, irrespective of the nationality of the aircraft performing that carriage." 98 The liability of a carrier for the death or injury of a passenger under the Convention is governed principally by art 17. Article 17, the terms of which are extracted in the judgment of Allsop P and Ipp JA (at [6]), has been interpreted by the highest Courts in Australia, the United States and the United Kingdom: see, among other authorities, Povey v Qantas Airways Ltd [2005] HCA 33; (2005) 223 CLR 189; Air France v Saks (1985) 470 US 392; Olympic Airways v Husain (2004) 540 US 644; Sidhu v British Airways plc [1997] AC 430; In re Deep Vein Thrombosis and Air Travel Group Litigation [2006] 1 AC 495. 99 Part IV of the CA Act (including s 28) applies to certain domestic air carrier operations that are not subject to the Convention. The Minister, in the second reading speech on the Civil Aviation (Carriers' Liability) Bill stated that the legislation: "extends the principles of the amended convention to all domestic carriage by air within federal competence but with certain modifications which are considered more appropriate for domestic purposes."

Commonwealth Senate, Parliamentary Debates (Hansard), 25 February 1959, at 187. See South Pacific Air Motive Pty Ltd v Magnus [1998] FCA 250; (1999) 87 FCR 301, at 342-343, per Sackville J. 100 The language of s 28 of the CA Act is very close to that of art 17(1) of the Convention, but not identical. The modifications to which the Minister referred in his second reading speech include substituting in s 28 the expression "personal injury" in place of the term "bodily injury" in the English translation of art 17(1) of the Convention. The difference in language was considered to be important in Magnus, where the Full Federal Court held that s 28, unlike art 17(1), applies to a claim by a passenger for damages in respect of purely psychological injury (as distinct from physical injury) resulting from an accident. 101 It should be noted that s 9B of the CA Act, which came into force on 24 January 2009, provides that the 1999 Montreal Convention for the Unification of Certain Rules for International Carriage by Air ("1999 Montreal Convention") has the force of law in Australia. Article 17(1) of the 1999 Montreal Convention is drafted in very similar terms to art 17(1) of the Convention. There is no occasion in the present case to consider whether the slight differences in language between the two articles have any significance.

The Issue 102 In the present case, there is no dispute that the respondent sustained "personal injury" when he fell after descending onto the portable step that the appellant's employees had placed on the tarmac at the foot of the aircraft steps. The question is therefore whether, in the language of s 28 of the CA Act, the personal injury resulted; "from an accident which took place on board the aircraft or in the course of any of the operations of embarking or disembarking ."

Reasoning 103 The parties are agreed that, in resolving this question, s 28 is to be construed in the same manner as art 17(1) of the Convention and that therefore the authorities on art 17(1), in particular those construing the word "accident", provide guidance on the meaning of s 28. 104 In Povey, the High Court followed the construction of "accident" in art 17(1) of the Convention adopted by the Supreme Court of the United States in Saks. The issue in Saks was whether a passenger who had become permanently deaf in one ear in consequence of the normal operations of the aircraft's pressurisation system, had suffered personal injury "resulting from an accident". The Supreme Court pointed out (at 399-400) that art 17(1) of the Convention refers to an accident which causes the injury rather than the injury itself. The Court concluded (at 405) that: "liability under Article 17 … arises only if a passenger's injury is caused by an unexpected or unusual event or happening that is external to the passenger." 105 O'Connor J, who wrote the opinion of the Court, observed (at 406) that: "when the injury indisputably results from the passenger's own internal reaction to the usual, normal, and expected operations of the aircraft, it has not been caused by an accident and article 17 of the [ Convention ] cannot apply." 106 In Povey, the question was whether a passenger on an international flight who suffered from deep vein thrombosis ("DVT") during the flight had done so as a result of an "accident". The joint judgment accepted (at 203 [28]) the analysis in Saks as the starting point. Their Honours held (at 205 [36]) that it was necessary to ask what had happened on board (or during embarking or disembarking) that caused the injury and whether what had happened was "unusual or unexpected". A passenger could not succeed unless something unusual or unexpected happened on board in the sense of a departure from the standard conditions of and procedures relating to air passenger travel: at 204 [31], 206-207 [40], [42]. Since nothing of this kind had been alleged by the passenger, his claim had to fail. 107 It might be thought that the present case falls comfortably within the concept of an "accident" as articulated in Saks and Povey. The primary Judge found that: o the portable step moved as the respondent placed his foot on it in the process of disembarking from the aircraft;

o this was an unusual or unexpected event because: "[i]t could never be said that a step used for passengers to reach the tarmac from an aircraft could be seen as behaving normally if it gave way";

o there was no act on the part of the respondent that caused the step to give way; and

o accordingly, the step gave way as the result of an external factor. 108 On the basis of these findings it does not seem difficult to conclude that something unexpected or unusual happened in the course of the respondent disembarking from the aircraft, namely (in the respondent's words) the "slipping from under [him]" of a portable step provided and placed on the tarmac by the appellant's employee. The event was external to the respondent since he was not responsible for the provision or placement of the step and, on the primary Judge's findings, he did not act in a manner that caused the step to give way. 109 Mr Williams QC, who appeared with Mr Stanton for the appellant, challenged the factual findings made by the primary Judge. However, he also argued that even if the findings stood (with the exception of the last), the primary Judge had erred in concluding that the respondent had suffered personal injury resulting from an "accident". 110 Mr Williams contended, first, that the respondent could not demonstrate that his injury was the result of an accident unless he could establish the reason why the step had moved when he put his weight on it in the course of disembarking from the aircraft. Since the primary Judge was unable, on the evidence, to determine what the cause was, the respondent had failed to make out his case. 111 Secondly, Mr Williams submitted that an event could not constitute an "accident" for the purposes of art 17(1) of the Convention or s 28 of the CA Act unless the passenger could show, in the language of the English Court of Appeal in Barclay v British Airways plc [2008] EWCA Civ 1419; [2009] 1 All ER 871, at 884 [35], that there had been: "a distinct event, not being part of the usual, normal and expected operation of the aircraft, which happens independently of anything done or omitted by the passenger ." (Emphasis added)

In the present case, so Mr Williams argued, the relevant event was the respondent putting his weight on the portable step. That event plainly did not happen " independently of anything done or omitted by the passenger ". 112 In In re Deep Vein Thrombosis the House of Lords concluded, as had the High Court in Povey, that a passenger who suffered DVT in the course of an international flight could not satisfy art 17(1) of the Convention. Lord Scott (with whom Lords Steyn and Walker and Baroness Hale expressed agreement) warned (at 503 [12]) about the danger of substituting judicial definitions for the language of the Convention: "…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." 113 As Lord Scott pointed out (at 504 [15]-[17]), the Supreme Court's formulation of the test in Saks was prompted by the particular facts of that case. Specifically, the requirement that the causative event be "external" to the passenger reflected the conclusion expressed by O'Connor J (540 US, at 406) quoted at [105] above. Lord Scott noted that O'Connor J recognised in Saks (at 405) the importance of a "flexibl[e]" application of the test she had formulated, taking into account "all the circumstances surrounding a passenger's injuries". 114 In Barclay, on which Mr Williams placed much reliance, the passenger had slipped on a plastic strip embedded in the floor of the aircraft as she was lowering herself into her seat. The plastic strips and the passenger seats installed on the aircraft were in accordance with the airline's usual standard for aircraft of that type and were not defective in any way. Moreover, the aircraft complied with all applicable aviation regulations. Laws LJ (with whom Thomas and Wilson LJJ agreed) emphasised (at 882 [27]) the requirement laid down by the authorities that an "accident", for the purposes of the Convention, is an unexpected event external to the passenger. His Lordship identified (at 883 [30]) the issue for resolution as follows: "When injury is caused by an event (here the slip) constituted by some contact or interaction between the passenger and the aeroplane in its normal state, is such an event an " accident " within art 17(1)?" 115 Laws LJ accepted (at 884 [32]) that the case could not turn on what the Supreme Court in Saks meant by the word "external", since that would amount to "interpreting an interpretation". However, the Court was required to deploy binding authority as a guide to the application of the Convention language to similar facts. The authorities had established (at [33]) that: "where injury is caused by an autonomous collapse in the passenger's health with which the aircraft environment had nothing to do, there is no accident." 116 Laws LJ observed (at 884 [34]) that if the passenger's case was good, art 17(1) would impose liability for a very wide range of injuries suffered on board an aircraft. Consequently: "[a]ny slip or fall resulting merely from contact with an inert piece of equipment, installed and operating as intended, would constitute an accident."

His Lordship concluded with the statement to which I have already referred (at [111] above) and which Mr Williams said applied to the present case. 117 Three points should be made about Barclay. First, as Mr Williams accepted, it is clearly distinguishable from the present case. In Barclay, the injury was received as the result of a passenger making contact with an "inert piece of equipment" properly installed and operating as intended. In the present case, the injury occurred as the result of the portable step "tipping up" when the passenger put his weight on it in the course of disembarking from the aircraft. A portable step is neither inert nor operating as intended if, when a passenger puts his or her weight on the step, it shifts sufficiently to cause the passenger to fall. 118 Secondly, in order to decide Barclay it was not necessary for Laws LJ to state that art 17(1) contemplates a distinct event, not being part of the usual, normal and expected operation of the aircraft, which happens "independently of anything done or omitted by the passenger". It was enough to conclude that a slip or fall resulting from contact with an inert piece of equipment, properly installed and operating as intended, could not constitute an accident. 119 Thirdly, with all due respect, I do not think that the statement of principle relied on by the appellant can be read literally. The Convention itself expressly acknowledges that a passenger may be able to recover notwithstanding that the damage was "caused by or contributed to by the negligence" of the injured passenger: art 21. The Convention therefore contemplates that a passenger may sustain an accident notwithstanding that he or she may have done or omitted to do something that contributed to the event causing the injury. Moreover, if the statement of principle were to be read literally, it would mean that a passenger would not be able to recover under the Convention if for example, he or she is struck by a hypodermic needle protruding from the fabric of the seat in front of him (cf Waxman v CIS Mexicana De Aviacion SA (1998) 13 F Supp 2d 508) or aggravates a pre-existing lumbo-sacral disc degeneration because of a defect in the lumbar support mechanism in the allocated aircraft seat (cf Malaysian Airline Systems Berhad v Krum [2005] VSCA 232). None of the leading authorities lends support to such a conclusion. 120 It is not necessary, in my view, in order for a passenger to succeed in a claim under art 17(1) of the Convention or s 28 of the CA Act, to show that the event causing injury occurred independently of anything done or omitted by the passenger. The conduct of the passenger may disentitle him or her from recovery if, for example, it is so out of the ordinary that the operations of the airline cannot be expected to deal with the conduct. An airline, for example, cannot necessarily be expected to provide a portable step sturdy enough to withstand the weight of a passenger who chooses to leap from the aircraft door directly onto the step, bypassing the steps attached to the aircraft. But the mere fact that the passenger has brought himself or herself into contact with a piece of equipment that is not operating in the usual, normal and expected way does not prevent the event from being an "accident" for the purposes of the Convention and s 28 of the CA Act. 121 Equally, in my opinion, it is not essential for a passenger to establish the reason why the aircraft, or the airline's equipment or services, did not operate in the usual or expected manner. What is required is proof that the injury was caused by an unexpected or unusual event that is external to the passenger: Povey, at 203 [28]. Moreover, as was pointed out in Saks, at 406, any injury is the product of a chain of causes and it is only necessary for the passenger to prove that some link in the chain was an unusual or unexpected event external to the passenger: see also Olympic Airways v Husain (2004) 540 US 644 at 653. Doubtless, in many cases, the passenger will adduce evidence of the reason or reasons why the aircraft, equipment or services did not operate in the usual or expected manner. But in some cases, for example when an aircraft simply disappears over an ocean and all passengers are lost, evidence as to the precise cause or causes of the catastrophe may not be available. Yet the crash of an aircraft in such circumstances is clearly an unexpected and unusual event external to the passenger. 122 These conclusions are consistent with the observations of Marrero DJ in Fulop v Malev Hungarian Airlines (2001) 175 F Supp 2d 651, at 657, quoted with approval by Lord Mance in In re Deep Vein Thrombosis Group Litigation [2006] 1 AC 495, at 521: "In so far as any decisive pattern may be discerned … the fulcrum of these considerations often rests on the extent to which the circumstances giving rise to the claimed accident fall within the causal purview or control of the carrier - or at least within its practical ability to influence - as an aspect of the operations of the aircraft or airline. The larger the role of the airline in the causal chain, and the greater the knowledge and involvement of its personnel and operations in bringing about the harmful event, the more likely it is that liability will be found. Conversely, as the causal balance shifts towards acts and conditions that are independent of the knowledge or will of the carrier, or not associated with the operation of the aircraft or airline nor arising from risks characteristic of air travel, and instead are more unique to the passenger alleging injury, the lesser the claimant's probability of recovery." 123 For these reasons, the fact that the respondent placed his weight on the portable step does not prevent the Saks test from being satisfied. On the findings made by the primary Judge, the respondent did nothing more than disembark from the aircraft in the usual way. The portable step did not, as the primary Judge found, "behav[e] normally". The appellant has not established that the primary Judge misinterpreted or misapplied s 28 of the CA Act. 124 I agree with Allsop P and Ipp JA that the factual findings made by the primary Judge were open to him and were correct. His Honour therefore correctly concluded that the respondent had established that his injury resulted from an accident which took place in the course of the operations of disembarking from the aircraft.

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