High Court of Australia Barwick C.J. Gibbs, Stephen, Mason and Murphy JJ. Connair Pty Ltd v Frederiksen [1979] HCA 25 ORDER Appeal dismissed with costs. Cur. adv. vult. The following written judgments were delivered:— June 20 Barwick C.J. In considering the material in the appeal book and the submissions of counsel, I have had the advantage of reading the reasons for judgment prepared by my brother Mason. The relevant facts, evidence and legislative provisions are there to be found. I have no need to supplement them in any respect. It is well settled, as my brother Mason points out, that for an applicant worker to obtain compensation under s. 9 (1) of the Workmen's Compensation Ordinance 1949 N.T., the disease from which he suffers or the stage a pre-existing disease has reached during his employment with the respondent employer must be due to the nature of the employment. Because of the extension of the definition of disease in s. 6 (1) to include the aggravation of an existing disease as itself relevantly a disease, I have expressed the recited law in the abovementioned terms. But whether it be the disease itself, or its aggravation, the worker's condition must be due, not to the particular incidents of a particular employment, but to the nature of the class or classification of employment in which he was engaged: perhaps "occupation" is the appropriate synonym for employment in this connexion. I agree that the statutory requirement of the relationship of the nature of the employment and the diseased state of the worker can be expressed by saying that some special risk of the onset or aggravation of the particular disease is inherent in the class of employment or occupation in which the worker was engaged. As my brother points out, the majority of the Federal Court and the primary judge, and indeed, in my opinion, the psychiatric specialist on whose evidence reliance has been placed also, were concerned with the causal relationship between the incidents of the particular employment and the worker's condition. They did not address themselves to the question whether the worker's state was due to the nature of the employment as distinct from the circumstances of the particular employment. The question for this Court is whether employment as a pilot in a commercial airline, or, if it matters, a small commercial airline, has a tendency inherent in the nature of that occupation to bring on, or to exacerbate a pre-existing mental condition, so as to exhibit a phobic fear of or antipathy to flying. The Court has no relevant findings of fact of the courts below and must determine this question for itself upon the material led in evidence before the primary judge. There are some employments which it may be thought a priori, have of their nature a tendency to cause or to aggravate particular physical or mental complaints. For my part, the conclusion of fact in The Commonwealth v. Rutledge [8] was that spying as an occupation had an inherent tendency to exacerbate paranoia already existing in an employee engaged in that occupation. There was expert evidence in that case which could support that conclusion. 1. (1964) 111 C.L.R. 1. The evidence in this case, however, has been concerned with the question whether the respondent's employment with Connair Pty. Ltd., including his experiences and frustration in that service, had caused his phobic condition. The expert evidence in the case was directed, and in my opinion only directed, to establish that causal relationship. There was, in my opinion, no evidence at all as to any particular risks of mental disease or its aggravation in the occupation of commercial flying, whether in a large or small commercial airline. I doubt if there are two categories of pilot employment so far as a question of the present kind is concerned, i.e. whether in large or small commercial operations. But, for the purposes of this discussion, I am prepared to assume that there are. I am unable to conclude, without relevant evidence, that there is any particular relevant risk inherent in the occupation of a commercial airline pilot in the service of a small airline. I have carefully considered the expert evidence in this case to see whether, although it was given alio intuitu, it affords a basis for a conclusion on a balance of probabilities that the employment of a pilot in a commercial, albeit a small commercial, airline carries an inherent risk of the onset or aggravation of a mental condition exhibiting a phobic fear of or antipathy to flying. Indeed, the evidence leaves me with the distinct impression that the respondent's condition, whether it was a new disease manifested for the first time in his employment with the appellant or an aggravation manifested during the currency of that employment of a pre-existing mental state, so far as it had any relationship to that employment, was the manifestation of his frustration with what was, in his opinion, careless, perhaps dangerous, methods of his employer and the effect of overwork due not to the nature of his employment but to the influence of Cyclone Tracy. Whether by appropriate evidence it could be established that a pilot in a commercial airline was by the very nature of that occupation at risk of the onset of a phobic condition of the kind with which the respondent became afflicted, whether as the result of an initial disease or of the aggravation of a pre-existing disease, may be a real question. But whether or not that could be established, neither possibility was established in this case. In my opinion, the appeal should be allowed and the application for compensation dismissed. Gibbs J. In January 1969 the respondent, who held an airline transport pilot's licence, commenced employment with the appellant company, which conducted a commercial airline whose activities were based on the Northern Territory. During the year 1975 he developed an anxiety state, one manifestation of which was a fear of flying. As a result of this condition he failed to satisfy the medical standards prescribed for renewal of his pilot's licence, and in March 1976 was informed by the Department of Transport that for this reason his licence would not be renewed. In the same month his employment with the appellant company was terminated. Subsequently he made an application for compensation under the Workmen's Compensation Ordinance 1949 N.T. ("the Ordinance"). His application succeeded before the Workmen's Compensation Tribunal, and also on appeal to the Supreme Court of the Northern Territory, although the Court corrected some errors in the determination of the Tribunal [1] . The Court determined that the respondent "developed a disease, namely a nervous disorder, due to the nature of the employment in which he was then employed by the [appellant] employer", and that as a result he has become permanently partially incapacitated for work: his incapacity for work as a pilot is total, but he can engage in other work. The amount of compensation payable was adjourned for further consideration. An appeal from this decision was brought to the Federal Court but was dismissed by a majority [2] . 1. (1977) 16 A.L.R. 148. 2. (1978) 20 A.L.R. 579. The respondent's claim to compensation was made under s. 9 (1) of the Ordinance, which is in the following terms: Where— (a) a workman is suffering from a disease and is thereby incapacitated for work; or (b) the death of a workman is caused by a disease, and the disease is due to the nature of the employment in which the workman was employed, his employer shall, subject to this Ordinance, be liable to pay compensation in accordance with this Ordinance as if the disease were a personal injury by accident arising out of or in the course of his employment. By s. 6 (1) of the Ordinance, it is provided that in the Ordinance, unless the contrary intention appears— "disease" includes any physical or mental ailment, disorder, defect or morbid condition, whether of sudden or gradual development, and also includes the aggravation, acceleration or recurrence of a pre-existing disease. No oral evidence was called before the Supreme Court; the parties were content to rely on the transcript of the evidence given before the Tribunal. It appears from the judgment given by Muirhead J. in the Supreme Court that he accepted the psychiatrist called on behalf of the respondent as a reliable expert witness, and that he regarded the respondent himself as an honest witness, notwithstanding that his evidence was in some respects rendered unreliable by his anxiety state. There is no suggestion that Muirhead J. took any different view of the credibility of the witnesses from that taken by the Tribunal, or that we should view it in any different light. The evidence of the respondent himself shows that from about April 1970 onwards he became concerned about the safety of the appellant's aircraft, particularly because of what he regarded as inadequate standards of maintenance and repair. He gave evidence of incidents when an aircraft engine failed or other defects appeared during flight, and of his complaints to the management and engineers of the airline, which he thought were disregarded. Evidence was given on behalf of the appellant that the standards of the airline were high, and its safety record good, and the learned trial judge found that "towards the end of his flying life the respondent must have been tilting at windmills". It is not necessary to attempt to decide whether any of the complaints made by the respondent were well-founded in fact, but it is not suggested that the respondent's concern was other than genuine. It may however be observed, without in any way reflecting on the airline, that one of the appellant's witnesses said that he himself had experienced engine failure in flight and had been forced on three occasions to land with his undercarriage either retracted or not locked down. The respondent was very disturbed by the cyclone which struck Darwin in December 1974. After the cyclone, because of the emergency then prevailing, he worked longer hours than usual and on occasions had to fly in bad weather and with heavy loads. In about May of 1975 he began to feel worried and apprehensive when he was flying, and in July, while on a check flight with another pilot, found that he could not carry out his duties in the aircraft. He sought and received medical treatment, after which, on 29th August 1975, he was certified fit to return to duty. Soon afterwards, while in an aircraft waiting to take off from the strip at Ayers Rock, he again "went to pieces" and was unable to pilot the aircraft. He has not since flown an aircraft and has even experienced feelings of great anxiety when being flown as a passenger. The psychiatrist who gave evidence was, according to Muirhead J., well-qualified and experienced. However, his evidence was not always lucidly expressed, and it contained some apparent inconsistencies. Its effect may be shortly stated as follows. The respondent had an obsessive and compulsive personality which predisposed him to the condition of phobia which he developed. This was a completely new condition, and it was caused by the displacement of an inner fear, of which the respondent was unconscious, so that it became consciously related to an outward object, viz. flying. The inner fear was of the respondent's own anger. That anger was mainly directed at the appellant, and principally because of the respondent's feeling that the appellant was not taking seriously his complaints about the aircraft he was called upon to fly, when he considered that the lives of himself and his passengers might have been at risk. He had other resentments—at his father, at the appellant for passing him over for a post which he had hoped to be given, and at those in authority for what he regarded as their unsatisfactory performance during the cyclone. And he had experienced distress at the illness and death of his brother-in-law. The psychiatrist said that he thought that the respondent's condition "was precipitated by the cyclone as a major stress". He explained that by the cyclone he meant the cyclone and its aftermath and he said: He [the respondent] has to go on working in a situation which is not ideal. He can cope with this for a certain time because of the %y(3)6D everyone has to deal with the difficult situation, but he is working a bit longer hours. He is working under stress, he is having to fly planes with more people in them. He does not see that the planes are as safe as they should be and for this he feels angry at Connair He repeatedly mentioned the stress caused to the respondent by the cyclone and its after-effects, but said that the cyclone was "not the only major stress". He gave the following evidence as to the effect of the incidents that suggested to the respondent that the aircraft were unsafe: Assuming again the obsessive compulsive personality, what significance do you think the sort of incidents about which Mr. Frederiksen told us yesterday, the safety incidents, would have in working towards or in bringing about the phobic condition? I think it would aggravate it. Anybody can break down if the pressures that are put on them are enough. The obsessive compulsive, however, personality is, perhaps stressed a bit more and is more likely to break down than another person. He is going to feel more resentful if these safety factors are not dealt with. He is going to feel that he is not being taken seriously and this leads to the development of the symptoms of tingling, headaches and getting uptight and scared of being in a plane situation. He also said: the fear situation I think is something new, the fear of planes situation, is something which has cropped up since the cyclone. When he was asked whether the respondent would have developed some sort of phobia if he had entered into some other occupation, for example, accountancy, he replied: It might have done if there was sufficient stress put on him, but you are not likely to have the same sort of stresses put on you in accountancy or other occupations as you are as a pilot where you have people's lives dependent on you. In argument before us, counsel for the appellant conceded that the respondent was suffering from a disease within the meaning of s. 9 (1) of the Ordinance. Further, it was not disputed that the respondent's employment with the appellant had contributed to cause his condition. The appellant's submission was that the evidence did not establish that the respondent's disease was "due to the nature of the employment" in which he was employed. The provisions of s. 9 (1) of the Ordinance, in their original form, were in substance identical with those of s. 10 (1) of the Commonwealth Employees' Compensation Act 1930-1956 Cth ("the Act") whose meaning has been considered in three decisions of this Court—The Commonwealth v. Bourne [3] ; The Commonwealth v. Thompson [4] , and The Commonwealth v. Rutledge [5] . By Ordinance No. 1 of 1970 a number of amendments have been made to s. 9, although s. 9 (1) itself has not been amended. Those amendments provide, inter alia, that where the workman was employed by two or more employers in employment the nature of which caused the disease, the compensation shall be recoverable from the employer who last employed the workman (sub-s. (1A)), and enable an employer against whom proceedings are brought and who alleges that the disease was contracted while the workman was in the employment of some other employer, to join the latter employer as a party (sub-s. (3B)). Moreover, by Ordinance No. 14 of 1977 there has been inserted in the Ordinance a new s. 9AA, sub-s. 1 of which, inter alia, has the effect that, "Without limiting the operation of section 9", where a workman who is suffering from a disease of a kind specified in the first column of the Fourth Schedule was, at any time before he became aware of the contraction of that disease, engaged as a workman in employment of a kind specified in the second column of that schedule opposite to the specification of that disease, then, for the purposes of the Ordinance, unless the contrary is established, that disease shall be deemed to be due to the nature of the employment in which that person was employed. 1. (1960) 104 C.L.R. 32. 2. (1960) 104 C.L.R. 48. 3. (1964) 111 C.L.R. 1. The source of the relevant words of s. 9(1) appears to have been s. 8 of the Workmen's Compensation Act, 1906 U.K. although the words that appeared in that section were "the disease is due to the nature of any employment in which the workman was employed". It was held by the House of Lords in Blatchford v. Staddon & Founds [6] that those words are not synonymous with the words "due to the employment", and that under s. 8 a workman was entitled to compensation if the disease was "incidental to that class of employment so that it" [could] "be attributed to service therein" [7] . The "employment" referred to in the section meant the work or process in which the workman was engaged, rather than his relationship with a particular employer [8] . The purpose of using the words "was to provide for ready recourse by the employee to the latest employer who employed him in work to the nature of which his complaint was due independently of the question whether working for that particular employer contributed at all to his condition ": The Commonwealth v. Bourne [9] , per Dixon C.J. In other words, once the workman proved that the employment was "of a nature to cause the particular disease" from which he was suffering, he was not required to prove that the disease in fact resulted from his employment with any particular employer: Hopwood v. Textile Paper Tube Co. Ltd. [10] . The workman was thus relieved of the necessity of showing that the actual employment with any particular employer caused or aggravated the disease. Although the test established by the English legislation was whether the disease was due to the nature of the employment, rather than whether it was due to the employment itself, the authorities are not opposed to the view that the fact that the disease was caused by the employment is in many if not most cases evidence that it was in the nature of the work to cause it. For although the eccentricities of animate behaviour may cause persons and animals to act contrary to their natures, the same is not true of employment, and when it is proved that a disease was caused by (and not merely contracted during) the employment, and it appears, either by proof or as a matter of common knowledge, that the incident, aspect or characteristic of the employment that caused the disease is one that would be expected to occur in employment of that class, it would seem to follow that the disease was due to the nature of the employment. And having regard to the objects of the legislation, and the purpose of using the words in question, it is difficult to believe that the legislature intended to place a workman under the burden of calling evidence either as to the manner in which employment of a particular kind is generally carried on by employers other than his own, or of the extent to which a particular disease is found to accompany the performance of employment of that kind. 1. [1927] A.C. 461. 2. [1927] A.C., at p. 470. 3. [1927] A.C., at p. 482. 4. (1960) 104 C.L.R., at p. 38. 5. [1946] 1 All E.R. 618, at p. 620. There is no decision of this Court that evidence that the employment in fact caused or aggravated the workman's disease is irrelevant to the issue whether the disease was due to the nature of the employment. The Commonwealth v. Bourne [11] and The Commonwealth v. Thompson [12] arose out of very similar facts; in each, an officer of the Taxation Department had died as a result of coronary disease, which was claimed to have been caused by the worry attendant upon the performance of his duties. It was held that the disease was not due to the nature of the officer's employment. However, in both cases the evidence failed to establish that the work in fact aggravated or accelerated the disease from which the employee was suffering: see, in The Commonwealth v. Bourne, per Dixon C.J. [13] , per Taylor J. [14] , and per Windeyer J. [15] and, in The Commonwealth v. Thompson, per Dixon C.J. [16] and per Taylor J. [17] . In the third decision, The Commonwealth v. Rutledge [18] , a clerical assistant in the Postmaster-General's Department was required to act as a spy to investigate suspected dishonesty on the part of her fellow employees. She suffered from latent paranoia, and the strain of her special duties resulted in a severe psychotic disorder. It was held that she was suffering from a disease due to the nature of her employment and was entitled to compensation. 1. (1960) 104 C.L.R. 32. 2. (1960) 104 C.L.R. 48. 3. (1960) 104 C.L.R., at p. 38. 4. (1960) 104 C.L.R., at p. 42. 5. (1960) 104 C.L.R., at p. 47. 6. (1960) 104 C.L.R., at p. 53. 7. (1960) 104 C.L.R., at p. 55. 8. (1964) 111 C.L.R. 1. There are in these three cases strong dicta by Taylor and Menzies JJ. that it is not enough to show that the disease from which the workman is suffering was aggravated or accelerated by the duties he or she was actually required to perform; see The Commonwealth v. Bourne, per Taylor J. [14] , per Menzies J. [19] ; in The Commonwealth v. Thompson, per Taylor J. [17] and per Menzies J. [17] and in The Commonwealth v. Rutledge, per Menzies J. [20] . If their Honours intended to do no more than emphasize that the test is whether the disease was due to the nature of the employment, their statements are incontrovertible. But if they intended to suggest that evidence that the disease was in fact caused, aggravated or accelerated by the employment is irrelevant to the question whether that test has been satisfied, or that in no case would such evidence be sufficient, I would respectfully disagree. If their remarks were intended to have that meaning they were no more than obiter, having regard to the facts to which I have already referred. 1. (1960) 104 C.L.R., at p. 42. 2. (1960) 104 C.L.R., at pp. 44-45. 3. (1960) 104 C.L.R., at p. 55. 4. (1960) 104 C.L.R., at p. 55. 5. (1964) 111 C.L.R., at p. 11. I am of the opinion that in the present case the evidence that showed that the respondent's disease was due to the actual circumstances of his employment was relevant to the issue. I need not consider whether such evidence would alone have been sufficient, because there was, in my opinion, further evidence that the disease was "due to the nature of the employment". I venture to doubt whether those words gain much in clarity by explanation and elaboration. However, if it is necessary to go beyond the words themselves in an attempt to elucidate their meaning, I would respectfully apply the tests suggested by Dixon C.J. in The Commonwealth v. Bourne [22] : I do not think that the expression "due to the nature of the employment in which the employee is engaged" covers an employment which has no particular tendency to give rise to a disease, contribute or conduce to it or accelerate it and no incident, adjunct or quality of which involves those employed therein in any particular liability to the contraction of the disease or to the aggravation or acceleration of its course. The word "nature" is a wide as well as a vague word and one must be careful not to narrow its application or attempt to reduce it to too much precision. But it does seem to refer to a connexion between the "disease" in the defined sense and the description of employment in virtue of its tendencies, incidents or characteristics. In the same case, Fullagar J. [23] , suggested that the workman must show that a characteristic or distinctive feature of the employment was a tendency to cause, aggravate or accelerate the disease, and added that the section only applies to cases where there is a special risk of contracting a particular disease or of suffering an aggravation or acceleration of a particular disease. He did not, however, suggest that the risk should be high, or that it was necessary that the employment should frequently or commonly cause the disease. The decision in The Commonwealth v. Rutledge is opposed to any such notion, since it can hardly be suggested that a person serving as a clerical employee in the Postmaster-General's Department runs a high risk of contracting a severe psychotic disorder, or of suffering an aggravation or acceleration of an existing disorder of that kind, or that there are many cases in which service in that capacity results in mental disease. Nor is it suggested that the risk must be one unique to the employment in question, and there is nothing in the words of the section to support such a suggestion. Further, there is no warrant for limiting the section to any particular sorts of disease—the Ordinance now does contain a schedule of what might be called industrial or occupational diseases, but s. 9AA makes it clear that the operation of s. 9 is not limited to diseases of that kind. 1. (1960) 104 C.L.R., at pp. 38-39. 2. (1960) 104 C.L.R., at p. 40. In the present case, it is clearly established on the balance of probabilities that the respondent had a personality which predisposed him to the anxiety state from which he now suffers. It is unimportant to decide whether that pre-existing condition was itself a disease, but in my opinion it was not. It is further established by the evidence of the psychiatrist that although the underlying cause was within the respondent's own mind, the disease was precipitated by the stresses to which he was subjected and under which he broke. Not all of those stresses were caused by his employment, but many of them were, including those that arose during the aftermath of the cyclone, and particularly those caused by flying aircraft he thought to be unsafe. Further, it is, in my opinion, established by the evidence, if indeed evidence is necessary, that stress is incidental to the work of a pilot, particularly perhaps in an airline flying small aircraft in a fairly remote area, as the appellant's airline was. In the course of flying, emergencies, or supposed emergencies, arise from time to time in the nature of things, as they did in fact in the employment of the respondent, and when they arise they tend to subject the pilot to stress which in some circumstances may be very great because of the possibility, or at least the fear, of serious danger to himself and his passengers. The employment of a pilot, in its nature, therefore has a tendency to give rise to any disease which is precipitated by stress. In other words, a pilot runs a special risk of contracting a disease which is due to stress. Where the stress-caused disease is an anxiety state, whose main symptom is a phobia of flying, there seems to me a close connexion between the disease and the nature of employment as a pilot. Such disease is incidental to that class of employment, whether or not it is an incident that commonly occurs. It is of course true that some of the stress which affected the respondent was caused by particular incidents of his actual employment, such as the occasions when he was required to fly in aircraft which he regarded as unsafe, and the conditions under which he worked after the cyclone. That does not mean that the stress was not due to the nature of his employment. The evidence shows that it is in the nature of employment as a pilot to undergo stress, and the incidents mentioned provide examples of that general truth. That being so, the anxiety state, precipitated by stress, was due to the nature of the respondent's employment. It is unnecessary for me to discuss at length the reasons for judgment given by Muirhead J.; it is sufficient to say that in my opinion his Honour applied the correct test and, in any case, reached the correct conclusion on the evidence. The majority of the Federal Court were correct in upholding his decision. I would dismiss the appeal. Stephen J. I agree with the reasons for judgment of the Chief Justice. The meaning and effect of s. 9(1) of the Workmen's Compensation Ordinance 1949 N.T. has been elucidated, in relation to the similar provision of the Commonwealth Employees' Compensation Act 1930, in The Commonwealth v. Bourne [24] and in The Commonwealth v. Thompson [25] : The Commonwealth v. Rutledge [26] involved no departure from but, rather, an application of these earlier decisions. 1. (1960) 104 C.L.R. 32. 2. (1960) 104 C.L.R. 48. 3. (1964) 111 C.L.R. 1. It follows that for an employee to obtain any entitlement to compensation under s. 9 (1) of the Ordinance his disease or its aggravation must be such as is shown to be due to the nature of his employment. This is, of course, no more than the very wording of s. 9 (1). It follows that some risk special to the nature of his class of employment must have eventuated. The evidence in this case was directed to the different and, as I think, irrelevant question whether the respondent's condition was causally related to his particular experience as an employee of the appellant. That testimony might, nonetheless, have provided evidence relevant to the respondent's claim under s. 9 (1). However, my reading of it has led me to the same conclusion as the Chief Justice: the respondent has failed to establish that the nature of his employment, that of a pilot in a small commercial airline, was such as to cause the condition from which he now suffers. I would allow this appeal. Mason J. Section 9 (1) of the Workmen's Compensation Ordinance 1949 N.T. provides: Where— (a) a workman is suffering from a disease and is thereby incapacitated for work; or (b) the death of a workman is caused by a disease, and the disease is due to the nature of the employment in which the workman was employed, his employer shall, subject to this Ordinance, be liable to pay compensation in accordance with this Ordinance as if the disease were a personal injury by accident arising out of or in the course of his employment. In this case we are confronted with the problem of applying the sub-section to an employee who is incapacitated for work as a pilot by reason of a mental ailment which takes the form of a phobia against, or fear of, flying. The answer to the problem hinges on the application of the words "and the disease is due to the nature of the employment in which the workman was employed". The meaning of these words in similar provisions in workers' compensation statutes has been settled by the course of judicial decision in the United Kingdom and, more importantly, in this Court. In The Commonwealth v. Bourne the Court held in a unanimous decision that the words "due to the nature of the employment in which the employee was engaged" in s. 10 (1) of the Commonwealth Employees' Compensation Act 1930-1956 referred to results which are incidental to the class of employment by virtue of its tendencies, incidents or characteristics, and that it was not concerned directly with something arising out of the particular service of the particular employee. Dixon C.J. [27] said that he did not think that the expression "due to the nature of the employment" covers an employment which has no particular tendency to give rise to a disease, contribute or conduce to it or accelerate it and no incident, adjunct or quality of which involves those employed therein in any particular liability to the contraction of the disease or to the aggravation or acceleration of its course. The phrase "nature of the employment" is, of course, no novelty in this context in the law of employers' liability: cf. s. 43 (1) of the Workmen's Compensation Act 1925 U.K.. In the provisions to which the use of the expression is to be traced the purpose of using the words "due to the nature of the employment" and not "due to the employment" was to provide for ready recourse by the employee to the latest employer who employed him in work to the nature of which his complaint was due independently of the question whether working for that particular employer contributed at all to his condition or aggravated it or accelerated its development; that employer could then claim over against a previous employer employing the claimant in work of a like nature and so on down the line. It was accordingly necessary to make the nature of the work the test and not the actual work done or the employment as it actually affected the man. In a not very full form sub-ss. (3) and (4) exhibit the same principle. In Blatchford v. Staddon & Founds [28] Lord Sumner said of the phrase: "In construing the Act effect must be given to the words "to the nature of". Their meaning cannot be the same as if the section had simply said "is due to" any employment. I think they are inserted because this part of the section is not concerned directly with something arising out of the particular service of the particular employer sued, but with results which are incidental to the class of employment, in which the workman has served several employers". 1. (1960) 104 C.L.R., at pp. 38-39. 2. [1927] A.C. 461, at p. 470. The employee, Bourne, was employed as an investigating officer in the Sales Tax Branch of the Taxation Department. He died from coronary sclerosis and myocardial degeneration while on annual leave. He had been engaged on a specific task of investigation of importance for eight months before his death and this apparently caused him great anxiety. There was evidence that the disease from which he suffered had progressively developed over a number of years. The Court found that the investigation of sales tax cases had nothing in its nature to cause, aggravate or accelerate vascular and cardiac degeneration and that his employment did not expose him to a special risk of attracting or suffering an aggravation or acceleration of any particular disease. In The Commonwealth v. Thompson [29] the Court, applying the same interpretation of s. 10 (1) of the Commonwealth Employees' Compensation Act 1930-1956, held that the heart disease from which an officer of the Department died was not due to the nature of his employment on the footing that it was not shown that the nature of his employment in the Department tended to cause or contribute to the attraction, aggravation or acceleration of coronary disease or of any of its consequences. 1. (1960) 104 C.L.R. 48. Subsequently, in The Commonwealth v. Rutledge [30] , an employee in the telephone accounts section of the P.M.G.'s Department who suffered from paranoia was required for little more than a week to carry out special duties involving the investigation of dishonest practices by other employees in the section. She was subjected to strain by these duties, with the result that she sustained a severe mental disturbance which incapacitated her for work. It was held by Taylor and Menzies JJ., Owen J. dissenting, that she was suffering from a disease due to the nature of her employment within s. 10 (1) of the Commonwealth Employees' Compensation Act 1930-1959. 1. (1964) 111 C.L.R. 1. The division of opinion in the Court related to the relationship between s. 10 (1) and the extended statutory definition of disease in s. 4 (1). The definition included "any physical or mental ailment, disorder, defect or morbid condition, whether of sudden or gradual development" and also included "the aggravation, acceleration or recurrence of a pre-existing disease". The majority held that "disease" in s. 10 (1) should be read in the light of the definition, whereas Owen J. thought that it had no application to the sub-section. The majority then applied s. 10 (1) as if the words "its aggravation, acceleration or occurrence" followed the word "disease" where it appeared thirdly and fourthly in the sub-section. They went on to hold that the nature of Rutledge's employment was such to expose her as a latent paranoiac to a special risk of being converted into an active psychotic. This was a finding of fact based on the evidence given in the case which has no relevance to the issue in the present case. In these cases the Court uniformly applied the interpretation of s. 10 (1) which it formulated in Bourne's Case [31] . The interpretation favoured by the majority in Rutledge's Case conformed to what had been said in the two earlier decisions, in particular, to the views expressed by Dixon C.J., Fullagar J. and Menzies J. in Bourne's Case [32] , and by Dixon C.J. and Windeyer J. in Thompson's Case [33] . 1. (1960) 104 C.L.R. 32. 2. (1960) 104 C.L.R., at pp. 39, 40, 44. 3. (1960) 104 C.L.R., at pp. 52-53, 56. The statutory definition of disease in s. 6 (1) of the Ordinance is in terms identical with the statutory definition of disease in the Commonwealth Employees' Compensation Act and it is common ground that the word "disease" where it thirdly and fourthly appears in s. 9 (1) of the Ordinance should be read in the light of the definition. The effect of the decisions is that the Commonwealth Employees' Compensation Act, and therefore the Ordinance, for it is indistinguishable from the statute, does not give an entitlement to compensation to an employee who is incapacitated by a disease not amounting to an injury, contracted in the course of a particular employment, unless it is due to the nature of that employment. This interpretation is not by any means remarkable. It is and always has been extremely difficult to prove that a disease was contracted in, or caused by, a particular employment. It was to meet this difficulty that provisions such as s. 43 (1) of the Workmen's Compensation Act, 1925 U.K. and s. 9 (1) of the Ordinance were enacted, their purpose being to enable an employee to recover if he could show that the employment in which he was engaged involved a particular liability to, or a special risk of, contracting the disease from which he suffered, although he could not prove that he contracted the disease in the employment of the defendant employer. The Ordinance confers on the defendant employer a right to join a prior employer as a party to the proceedings and if it be proved that the disease was contracted while the employee was in the employment of that employer compensation, if payable, is recoverable from that employer (s. 9 (3B)), subject to his recovering from the later employer an amount in respect of any aggravation or acceleration of the disease that may have occurred in the later employment (s. 9 (3C)). Workers' compensation legislation has acknowledged the need to provide for compensation for incapacity due to injury arising out of or in the course of employment, though it was not always so. For some time the legislation insisted on the co-existence of both causal and temporal connexions. But the legislation has made separate and different provision for disease and this in itself is not without significance. It was thought initially that the predecessors of s. 9 (1) were directed to the so-called "occupational diseases" or "industrial diseases" as they are sometimes called, such as silicosis. This conception of the provisions has been overtaken by later developments with the result that the sub-section is now applied to mental and psychological disorders and to cardiac and vascular conditions. I shall refer briefly to some of these developments. A broader interpretation of "injury" has been established by judicial decision so that in some statutes at least it extends to diseases having a bacterial or viral origin in the absence of a limiting context—see Brintons Ltd. v. Turvey [34] ; Grant v. Kynoch [35] ; Martin v. Manchester Corporation [36] ; Hutchinson v. Kiveton Park Colliery Co Ltd. [37] : cf. Slazengers (Australia) Pty. Ltd. v. Burnett [38] ; Darling Island Stevedoring and Lighterage Co. Ltd. v. Hussey [39] ; Favelle Mort Ltd. v. Murray [40] . 1. [1905] A.C. 230. 2. (1919) 12 B.W.C.C. 78. 3. (1912) 5 B.W.C.C. 259, at p. 262. 4. [1926] 1 K.B. 279, at p. 291. 5. [1951] A.C. 13, at p. 20. 6. (1959) 102 C.L.R. 482. 7. (1976) 133 C.L.R. 580. The statutory definition of injury in s. 6 (1) of the Ordinance is not so expressed as to include any disease or any class of disease, as does the statutory definition of injury in s. 6 (1) of the Workers' Compensation Act, 1926 N.S.W.. Consequently, the considerations which led the Privy Council in Slazengers' Case [41] and this Court in the Darling Island Case to conclude that a disease could not be an injury unless it fell within the express inclusion within the definition have no application here. For the same reason the division of opinion between the members of this Court in Favelle Mort on the same question may be put aside. Under the Ordinance an infection due to the entry into the body of bacteria or a virus is an injury, though it also answers the statutory description of "disease". The result, and it is of some importance, is that in all those cases in which incapacity is produced by a disease which is also an injury, the employee can recover if the injury arises out of or in the course of his employment (s. 7 (1)). 1. [1951] A.C. 13. This expansion of "injury" by judicial interpretation has been accompanied by extensions of the statutory definitions of "disease". It is defined by s. 6 (1) of the Ordinance as follows: "disease" includes any physical or mental ailment, disorder, defect or morbid condition, whether of sudden or gradual development, and also includes the aggravation, acceleration or recurrence of a pre-existing disease. For present purposes the importance of the definition is that it includes aggravation, acceleration or recurrence of a disease. This extension of the definition, read in conjunction with s. 9 (1), has resulted in a considerable expansion in the area of operation of that sub-section. There are many employments of which it may be said that, although they have no tendency to cause a particular disease to be contracted, they have a tendency to aggravate or accelerate that disease. Rutledge's Case [42] is an example. The nature of the work there was held to be such as to aggravate the applicant's condition of latent paranoia; but the nature of the work was not such as to bring that condition into existence. 1. (1964) 111 C.L.R. 1. The issue for this Court is whether the Full Court of the Federal Court correctly applied s. 9 (1). The evidence was that the respondent suffered from an obsessive compulsive personality which developed into a phobia against flying. The question for the Court was whether the respondent's employment as a pilot with the appellant in a commercial airline had a tendency to cause, aggravate or accelerate that condition, or, to put it in other words, whether that employment involved a particular liability or special risk of that kind. In my opinion the majority in the Full Court did not direct their attention to this question. St.John J. said [43] : There is no mention in Rutledge's Case of any evidence that there was a general tendency to spur latent paranoia into activity. The application of the principle enunciated in Bourne's Case [44] to the facts of Rutledge's Case leaves scope for concluding that the particular effect of the work done can be substituted for general tendency in the formulation of the principle to be applied. It is quite evident from this passage that his Honour misconceived the effect of Rutledge's Case. He attributed to the decision in that case a denial of the principle on which Bourne's Case had been decided. 1. (1978) 20 A.L.R., at p. 596. 2. (1960) 104 C.L.R. 32. Gallop J. said [45] : A workman might also more readily be entitled to compensation if the disease due to the nature of his employment is a recently contracted disease rather than a contraction of gradual development or the aggravation, acceleration or recurrence of a pre-existing disease. In such case a workman may not have to contend with the complicating background of a pre-disposed disposition or history of symptoms which may or may not be described as a disease. Likewise from a factual point of view the length of time during which the workman had been employed in a particular class of employment or on a particular task as part of that employment may be important in determining as a matter of fact whether the contraction of the disease was due to the nature of the employment, or was due to some other circumstances unrelated to the employment, such as contraction from an outside source, or the natural progression of a pre-existing condition, not aggravated or accelerated by the employment. In other words, it may be that the duration of the employment generally or of the performance of a particular task may be an indication that the disease was contracted during and was due to the nature of that employment. The shorter the employment or performance of a particular task, the more difficult it may be to establish as a fact the necessary connection between the disease and the employment or task. These observations are again inconsistent with Bourne's Case and indicate that his Honour was directing his attention to the question of causal connexion between the disease and the employment or task in which the employee was engaged. 1. (1978) 20 A.L.R., at p. 602. It follows that the majority in the Full Court misdirected themselves and that they failed to consider the real question for determination, namely, whether the evidence established the requisite tendency in the employment of the respondent as a pilot in a commercial airline or a small commercial airline to cause, aggravate or accelerate the condition from which he suffered. The evidence relied upon to support an affirmative answer to that question was that of Dr. Litt, a psychiatrist. He gave this evidence: Q. Are there any sorts of occupations where that sort of personality would be an advantage? A. You see this at various levels and this is the level that lieutenant-colonels get to in the army. You see this in accountants; but where it can get out of kilter is like with one patient I had who was an accountant who was an obsessive compulsive. He had to check his figures. He had to check his figures every time he was adding up a row of figures. He had to add them up 21 times. He got the same answer each time, but he was unconsciously compelled to go for this 21 times. He was very good at his work, but in doing this he would also slow it up, so he got through a much smaller amount of work than the other people he was working with. That is a sort of extension where the excessive compulsive starts to become abnormal. Q. All other things being equal and all technical ability being—assuming technical ability—equal, would this sort of personality assist a person who was a pilot? A. I think it would. He would be conscientious. He would do his checks adequately. Everything would be run by the book, he would get upset and he would get worried. Later, the doctor gave this evidence: Q. How did this relate to flying or aircraft? A. He felt angry and resentful at Connair. This is the thing, in talking to Mr. Frederiksen, that comes out time after time, the feeling that this is a group of people who are not taking him seriously. He makes complaints about his plane. If he does not take them seriously first of all he is put in a life-threatening situation, he himself may die but also his passengers may die too if they do not take seriously what he says. Q. Can you express any opinion as to the likelihood of this phobic condition being related to flying aeroplanes developing in someone who was not in fact flying aeroplanes? A. Many people have the fear of flying, but this again—it is not just the fear of "the plane may crash". It is usually read as some other fear, as I mentioned earlier on, of what they might do in a situation where they may break down. Is that what you are looking for? Q. What I am asking you doctor is whether a person who is not a pilot would be likely to develop the same sort of phobia to flying that Mr. Frederiksen has? A. They may do for other reasons but I think it is more pertinent to him because this is his occupation. This is what he has always wanted to do. It is what he struggled to do. He struggled against his father and he put himself through flying and he has got his scholarships and he is always trying to do well, so it is a major thing for him to have to give this up. Q. Assuming then that the predisposed obsessive compulsive personality and the after result of the development of a phobic condition, am I right in saying "after result"? Is it in fact an after result of things that have happened? A. I think it was precipitated by the cyclone as the major stress, and it was a major stressful situation, and not just for him but for everybody else who went through this. Q. In what way, doctor, assuming the history that Mr. Frederiksen has given in the witness box, in the history of a hypothetical patient—in what way would you see the cyclone and the aftermath as being related to the triggering off of the phobic condition? A. He has to go on working in a situation which is not ideal. He can cope with this for a certain time because of the everyone has to deal with the difficult situation, but he is working a bit longer hours. He is working under stress, he is having to fly planes with more people in them. He does not see that the planes are as safe as they should be and for this he feels angry at Connair. There is a great deal of anger expressed at Connair and the way they did not cope with their planes and they did not deal with his complaint and he felt he was being brushed off. And these all tend to make him feel more resentful and as this anger builds up and he can do little about it, this is where his phobic symptoms start. Q. Given that pre-existing personality, if he had entered into some other occupation, for example, accountancy, do you consider that he might have developed some sort of unusual phobia in that field, for example, having to count through his figures 21 times? A. It might have done if there was sufficient stress put on him, but you are not likely to have the same sort of stresses put on you in accountancy or other occupations as you are as a pilot where you have people's lives dependent on you. Q. do you consider that his phobia against flying would have become manifest if he was with another airline, under much the same circumstances, that is, circumstances of the cyclone, of his problems with his family, of his referring to certain defects in the aircraft and, should I add, perhaps some reaction against one of the members of the company concerned? Do you consider that was peculiarly ? A. especially his attitude to the company and his not being taken serious (sic) when he pointed out things that were going wrong, yes, I think it would have. These passages certainly demonstrate that the respondent's employment had the effect of causing, aggravating or accelerating his phobia against flying. Do they also show that his employment as a pilot in a commercial or a small commercial airline had a tendency to cause, aggravate or accelerate such a phobia? Much of the evidence lacked the requisite generality because the witness was preoccupied with the impact of the employment on the respondent's personality. The witness apparently believed, mistakenly in my view, that it was necessary to prove the employment caused or contributed to the development of the phobia. However, to my mind the witness said enough to demonstrate that employment as a pilot in a commercial or small commercial airline involved some special risk of producing in a person with an obsessive compulsive personality a phobia against flying. On this question, I respectfully disagree with the conclusion reached by Bowen C.J. in the Federal Court. It emerged from the answers which I have quoted that employment as a pilot had the necessary tendency because it tended to cause or exacerbate the phobia to a greater degree than employment in other occupations. I do not think that the tendency has to be exclusive to employment of the kind in question. It is enough if the tendency to expose the employee to the risk of contracting, aggravating or accelerating the disease distinguishes the employment from most, if not all, other employments. This in one sense is by the way, because the evidence indicates that the risk in the respondent's employment as a pilot was greater than that involved in other occupations. The expert evidence, slight and confused though it is, confirms one's impression as a layman that if a person with an obsessive compulsive personality is employed as a pilot, employment in that capacity will expose him to a special, if not unique, risk of developing a phobia against flying or of aggravating or accelerating that phobia. The consequence is that in my opinion there was evidence on which the Full Court of the Federal Court, had it correctly applied s. 9 (1), could, and should, have found that the respondent was incapacitated for work by a disease which was due to the nature of the employment in which he was engaged. The same comment of necessity applies to the Supreme Court of the Northern Territory (Muirhead J.) from whose judgment an appeal was taken to the Full Court of the Federal Court. Although his Honour found for the respondent, he appears to have based that finding on the conclusion that the evidence established a causal connexion between the disease and the employment. In the result I would dismiss the appeal. Murphy J. I agree generally with what has been said by Gibbs J. The words, "disease due to the nature of the employment", in the Workmen's Compensation Ordinance 1949 N.T. are satisfied if it is proved that the disease is due to the employment. The effect of previous construction of similar legislation is that even if the disease is not proved to be due to the employment, it may still be due to the nature of the employment (see Blatchford v. Staddon & Founds [46] ; The Commonwealth v. Bourne [47] ). 1. [1927] A.C. 461. 2. (1960) 104 C.L.R. 32. In my opinion, it is sufficient but not necessary if the applicant shows that the disease was due to the employment. The contrary view would lead to the result that a disease which is not due to the employment may be held to be due to the nature of the employment and compensable, but one which is due to the employment may be held to be not due to the nature of the employment and not compensable. In workers' compensation legislation, this would be ludicrous. The appeal should be dismissed.