Select Committee on Science and Technology Fifth Report


8.1 In this Chapter, we consider some of the main non-medical matters arising from our Inquiry, namely: the lack of direct high-level responsibility for aviation health; some complacency over that unsatisfactory state of affairs; the lack of directly relevant basic factual material and of accessible health information; the poor awareness of fitness-to-fly issues; and the airline industry's handling of the public.

Responsibility for health

8.2 From the earliest days of civil aviation, safety was the main concern. When the international nature of the developing airline industry was formally recognised by the establishment of ICAO in the 1940s, the organisation's fundamental purpose, as noted in paragraph 3.5, was set as ensuring that the development of commercial aviation proceeded in a safe and orderly manner.

8.3 The national bodies that ought to have direct interests in passenger and crew health are noted in paragraphs 3.18 to 3.21. We were surprised that, although DoH accepted some responsibilities for advising the medical profession and the public on aviation-related (as other) health questions, it regarded DETR as in the lead on aviation health (Q 509). While the DETR Minister accepted the lead (QQ 509 & 555), the Department had exhibited a certain lack of vigour. When our Inquiry began, for example, there was no centrally commissioned research into the health effects of air travel (QQ 12 & 13). By the time our evidence-taking was drawing to a close, the gap was acknowledged by the Minister's announcement of new research, explicitly prompted by the Inquiry (Q 516), and discussed further in paragraphs 9.2ff.

8.4 CAA's responsibilities are focused on air safety. Any involvement in passenger health or comfort arises only indirectly as a consequence of safety, particularly in relation to emergency evacuation from aircraft (p 1). CAA does not address long-term health effects from flying (p 16) even in relation to flight crew (p 1, Q 60).

8.5 HSE has general oversight of employees' health and safety but, as noted in paragraph 3.21, commercial aircraft are largely exempt from the provisions of UK health and safety at work legislation. As regards the remaining relevant provisions, HSE avoids overlapping responsibilities with CAA under a memorandum of understanding, leaving the lead essentially with CAA.

8.6 On the international scene, JAA also stated that their primary concern was with safety and that their position on flight crew and passenger health was the same as CAA's (p 130). However, JAA recognised that passenger health might become more important in the future development of aviation. Indeed, they have set up a working group to examine this - although, reflecting JAA's general remit, the approach will continue to be strongly linked to air safety (p 130).

8.7 The lead on aviation health is, in our view, unacceptably weak. However, even in relation to safety - the main purpose of present national and international regulatory structures - the centre of gravity is not obvious. A full range of safety rules and regulations is in place under ICAO, but changing them seems remarkably difficult. Although ICAO has the authority, the reality is that it is governed by its member States. For things to progress in ICAO, members not only have to promote them strongly from below, but they may also have to deal laterally with regional organisations like JAA and the European Union at the same time (QQ 3-6, 71 & 72). This is a recipe for inaction: as an organisation, ICAO can wait for Member States' initiatives; and member States can wait for ICAO's lead. JAA is in a similar position (QQ 347 & 378). We recommend the United Kingdom and other governments to do everything they can to reduce inertia within the international safety-focused regulatory structures.

Complacency about health

8.8 DETR accepted that, over the years, airline passenger health had generally been "grafted on" to existing structures and ran the risk that they could "slip between the cracks" or be subject to "regulatory overlap". It was their view that primary responsibility for ensuring an acceptable aircraft cabin environment lay with the airline industry and that passengers themselves had a responsibility to ensure that they were fit to fly (Q 2). We agree with the latter point but, as discussed in paragraphs 8.29ff, we are clear that more needs to be done to enable passengers to assess their fitness.

8.9 Safety is paramount in the airline industry and nobody would wish it otherwise. Our concern is not that health is secondary to safety but that it has been woefully neglected. We welcome DETR's belated acceptance[101] that it has the lead within the United Kingdom, and we recommend the Government to ensure that concern for passenger and crew health becomes a firm priority.

8.10 It remains the case that there is no international regulatory focus for monitoring and developing practices and procedures on passenger and crew health. We recommend the Government actively to pursue the strong UK interest in passenger and crew health through its international contacts with JAA, ICAO and other appropriate organisations, and we urge them all actively to promote health. This will both benefit air travellers in other countries and also help to minimise the possible impact of greater attention to health on competition within the international airline industry.

8.11 In the effective national (and international) policy vacuum on passenger health and comfort noted above, aircraft manufacturers and airlines have accepted responsibility. Both directly and through airline representative bodies, they professed high ideals (pp 99, 104, 107, 110, 224 & 229). We were surprised, however, at the degree of complacency amongst them.

8.12 AUC and the airlines are understandably concerned not to scare the travelling public (pp 57, 99 & 104). As British Airways stated, "we want to be absolutely honest with the customers and potential customers, but we do not want to frighten them" (Q 323). But such honesty requires an acknowledgement of risk and uncertainty where that exists. The representative of ATA told us that, while USA-based airlines often had a small general health brief in in-flight publications, it did not include DVT - because they could "not say definitively that there is a direct causal relationship between air travel and DVT and, as such, we do not wish to frighten our passengers unnecessarily" (Q 302).

8.13 On behalf of British airlines, BATA did not consider that there were any significant health issues about which they should have serious concerns currently (p104); ATA (p 110) had similar views. British Airways felt that much of the public concern about health in the cabin environment was only anecdotal (Q 310)[102]. The airline Emirates stated that there was no evidence to suggest that the cabin environment was unhealthy or adversely affected passengers or crew (p 229).

8.14 Among the manufacturers, Boeing felt the need for more research into the possible causes of flight crew and passenger symptoms and complaints (p 204). Airbus Industrie said they were "ready to consider improvements to aircraft design if there is a clear link with passenger or crew health" (p 165).

8.15 We had expected AUC (set up by CAA to represent the interests of air passengers to regulatory authorities and service providers) to help get attention focused on these matters. However, it had no human or material resources to commission research and was essentially reactive, although its representatives said they would lobby for regulatory change if they thought it was necessary (p 57, QQ 157-169).

8.16 The charge made by Mr Kahn (Q 94) that the industry was "in a state of denial" about passenger health was considered as reasonably fair by the Consumers' Association (Q 206) and not disputed by the AUC (Q 208). The charge is perhaps a harsh one, but the industry could do more to avoid such charges. To all those with responsibilities for passenger and crew health, we have to say that absence of evidence of harm is not the same as evidence of the absence of harm. Without succumbing to the impossible counsel of perfection that everything should be demonstrated to be completely safe in all possible circumstances, there is much scope not only for more positive responses to health issues when they are raised, but also for pro-activity in detecting, examining and dealing with new and emerging concerns.

Lack of basic factual material

8.17 As noted in paragraph 2.9, the starting point of our Inquiry was to be a review of current knowledge about the health implications of the commercial aircraft cabin environment and the extent to which this informed current practice. While we acknowledged the possibility that there might be some gaps in that knowledge, we were surprised to find that there were so many. There are very few published or easily available recorded data on the majority of questions in which we were interested. In the absence of the facts, it is not surprising that there is also a serious lack of knowledge about the relationships between aircraft cabin environment factors and health, particularly in relation to cabin occupants already in a poor state of health. In the absence of accessible and authoritative information, it is not surprising that rumour and speculation thrive.


8.18 We were told many times that, with the rapid development of commercial aviation in recent years, the demographic spectrum of travellers has been widening as air travel has become increasingly attractive and available to the general public. While that coincides with common sense, none of our witnesses provided detailed factual evidence to support this.

8.19 As noted in paragraph 3.51, CAA recently commissioned research to study the size and shape of aircraft passengers to enable them to set appropriate safety standards for emergency evacuations. What needs to be known in terms of passenger health encompasses a much broader range of issues. To enable proper judgements to be made about any potentially adverse impact of cabin environment factors on travellers' health, various facts about the flying public are required - as a minimum, material on their age, sex, height, weight, social status and general health status, in each case associated with the class and duration of travel.

8.20 Such data are not available. On our behalf, the Parliamentary Office of Science and Technology conducted extensive searches for this sort of material and was able to find only the limited material outlined in Box 1 (see paragraph 2.3) covering a few general conclusions about trends in UK-origin leisure and business travel.


8.21 Epidemiology is the study of the statistics of health and disease, in particular the presence and incidence of ill health in a selected population, and its relationship with factors of medical or environmental significance. It can be a very powerful tool in understanding complex interactions of factors. Whilst there have been some recent small-scale studies on DVT in travellers (see paragraph 6.16), the general epidemiology of ill health connected with flying is non-existent. Moreover, that knowledge could not be established quickly because, as noted in paragraph 7.73, a standardised basis for reporting in-flight medical incidents is only just about to be introduced, and there are no formal systems for detecting and reporting post-flight ill health.

8.22 There have been some studies on symptom or sickness reports from aircrew, usually in response to complaints about the aircraft cabin environment (pp 204, 213 & 245), but self-reporting or anecdotal studies of this type are of very limited scientific value and may indicate only where more formal research is needed.

8.23 Professor Sir Colin Berry, Professor Denison and Dr Murray all suggested that study of aircrew medical records should provide valuable information on any long-term effects on health from disinsection and other potentially hazardous cabin factors (QQ 224 & 231-235). However, we were surprised to find that systematic recording over time of the health status of flight crew or cabin crew is not carried out by licensing authorities or airlines (see paragraphs 3.44ff). Thus, apart from mortality data on flight crew obtained by research on company pension records[103], there are no recorded data on crew health by which retrospective epidemiological studies could be carried out. CAA has proposed carrying out further studies on pilot licence medical records, but these are currently in abeyance (p 39) and, in any case, may not contain morbidity (illness) information useful for assessing long-term health.


8.24 The design parameters for the aircraft cabin environment have largely been set to maintain efficient operational performance by flight crew, based on a wealth of laboratory and field investigations (pp 86 & 251, Q 47). As a result of the selection and accreditation process, flight crew are people in robust health. However, some passengers will be in less than full health, and there appears to be little or no soundly-based knowledge about the potential for adverse impact of cabin environment conditions on them, or on those who might have personal risk factors which could render them vulnerable to conditions in the aircraft cabin.

8.25 Additionally, much of the evidence given to us about the health effects of flying is based either on anecdote, which is scientifically unreliable, or on extrapolation from studies carried out in ground environments, notably in relation to DVT (see paragraphs 6.13-6.14) which is also scientifically unsound. As discussed in previous Chapters, the cabin environment at cruising altitude is very different from any ground environment, not only in many individual respects but also, and particularly, in the potential for interplay between those effects.


8.26 The various deficiencies noted in the preceding paragraphs severely limit the amount of medical knowledge on which advice to intending passengers can be based. For example, the AUC told us that they had agreed with DETR to expand the currently brief section in their booklet Flight Plan on general medical advice to intending passengers. They said that one of the reasons why this had not already been done was that they were not sure what to say in it. They noted significant gaps in research that needed to be filled, particularly on DVT, before they could advise people what they should do (Q 171). We were also pleased to note that DoH planned to extend and improve the guidance it provides to the public (in Health Advice for Travellers), at least in relation to DVT (Q 544).

8.27 The absence of a broad and detailed knowledge base means that neither the general public, nor their professional health advisers, can easily obtain reliable high-quality information, particularly about unusual sets of circumstances. The implications of this for individuals' assessment of any potential health risks from the aircraft cabin environment about which they may be concerned are discussed further in the next section.

8.28 Given these gaps in the knowledge base, we were pleased to hear about the DETR/DoH research proposal noted in paragraph 8.3. Drawing on the points made throughout this Report, our suggestions for the topics needing to be covered are summarised in paragraph 9.3.

Lack of accessible health information


8.29 The principal sources of initial advice and guidance to members of the public on flying and health are either official publications or articles in the media. The two official publications are Health Advice for Travellers (DoH) and Flight Plan (AUC)[104]. However, unless these are provided with the tickets at the time of booking, the public is unlikely to be aware of their existence. In addition, the information contained in the editions current during our Inquiry[105] was very general. Neither contained any information on health related to the aircraft cabin environment itself, nor on additional risks to those whose health was already poor.

8.30 Neither publication would be of any assistance to someone not in robust health seeking information on which to base a decision on whether to fly - or even whether they needed to seek professional advice. The question is how people are to judge this for themselves without carefully framed guidance - such as the risk categories we have proposed in relation to DVT (see paragraph 0).

8.31 AsMA drew our attention (p 198) to the leaflet Useful Tips for Airline Travel that they publish with the ATA. This usefully outlines the main features of the cabin environment and contains helpful advice. While it does not refer to DVT explicitly, it does encourage movement "to prevent leg compression and blood pooling" and notes that "one good exercise is to flex and extend the ankle joint every 20-30 minutes". It advises intending passengers to delay their trip if they are not well or have a contagious disease and to consult their physician if they have a history of blood clotting disorders or have any other questions about their fitness to fly.

8.32 Another source of information for passengers is the airlines themselves. The material most obviously targeted at passengers is in airlines' in-flight magazines (p 124), although it is open to question how many passengers read the health-related articles they may contain other than by chance. We noted that the half-page guide to "good health for travellers" in the May 2000 edition of British Airway's in-flight magazine High Life was about three-quarters of the way through its 200 pages. The guide contained advice on exercise to avoid "blood circulation from becoming sluggish, something which can happen if you sit still for a long period, which might cause circulatory problems for some people". However, all this was accompanied by a stern warning that a doctor should be consulted before starting the exercise programme and that, by participating in it, passengers released the airline from any responsibility for any health consequences that might arise as a result.

8.33 British Airways have recently introduced a pre-flight travel guide, Fly, that is issued with their tickets (Q 319). While the Summer 2000 edition we saw made no reference to in-flight health, British Airways confirmed during the evidence session (Q 325) and in later correspondence that they planned to include appropriate material within it, alongside the development of health-related information on their web site[106]. We understand that other aviation organisations are also developing the provision of flight health information over the Internet.

8.34 Airlines and their agents are in the front line of selling tickets to passengers. In our view, they could and should do a great deal more to inform their passengers about air-travel health issues. We make more concrete proposals in paragraphs 9.5ff.


8.35 An important source of information for passengers is journalism. The challenge for journalists in this area is to provide accurate information without causing unnecessary concern[107], particularly among those who have some fear of flying - who, as Mr McKenzie Buchanan noted (Appendix 4), probably number many more than those who openly admit it. This calls for careful judgement about language and presentation. It cannot be right to side-step potential health problems by knowingly underplaying the significance of cabin factors for health. It is equally unacceptable to overplay the health significance of such factors.

8.36 In our recent Report Science and Society[108], we commented extensively on the role of the press and other media in informing and educating the public on scientific matters, and of the need for them to act responsibly in presenting sometimes complex questions of uncertainty and risk. All those points apply in the handling of information about the health effects of flying, and we again commend to journalists the guidance outlined in Chapter 7 of Science and Society.

8.37 It is entirely possible to deal with aviation health in a balanced way that develops awareness, knowledge and understanding of the complicated and potentially emotive questions that arise. For example, we commend a series of Consumers' Association reports recently published in Holiday Which? namely In-flight medical emergencies (January 1996); Health in the air (Winter 1999); and Are you sitting comfortably? (Spring 2000). Journalism is not always so balanced. In Box 6 are some sample headlines of articles published during our Inquiry. We understand the importance of a headline in gaining the reader's attention and, as noted, some of these do so in a reasonable manner. The others seem to us to be arguably sensational.

8.38 Sensationalism is sometimes continued in the articles themselves. In this connection, we must comment briefly on the work of Mr Farrol Kahn, who was either the author of, or a substantial source for the views quoted in, a number of these. Mr Kahn has done a lot to raise the profile of flying and health, and we felt that his contribution could be helpful in our deliberations. His written evidence was broad-ranging and peppered with apparently impressive references (p 44). Disappointingly, these did not stand up to examination (QQ 87-151). For example, in paragraph 24 of his memorandum (p 44), Mr Kahn implied that Kenyon et al supported his contention that filters were changed less frequently than specified. During his oral evidence, Mr Kahn seemed first to confirm this (Q 138) but later attributed the view to Professor Hocking (Q 143). Separately, Professor Hocking stated that, to the best of his knowledge, he had not published any information on this (p 236). After several reminders, Mr Kahn said in correspondence that the attribution to Professor Hocking was a mistake and he could not provide the confirmatory material he had offered (Q 144) as this had been given to him in confidence.

8.39 During examination, Mr Kahn said that he was not a doctor or scientist, but was an interested observer, medical writer and journalist (QQ 109, 113 & 147). He claimed to be a medical expert "by accretion" (Q 109), but his expertise is limited. As Dr Giangrande noted (p 234), the view half-attributed to him by Mr Kahn that "when you breathe in and out you are not replenishing your blood plasma" (QQ 108 & 109) is nonsense. This carelessness with facts is not limited to medical or technical points. Mr Kahn's paraphrase of British Airways' rejection of his request for research funding ("passenger health is not a Board-approved priority theme" - Q 128) is not the obvious intent of the letter[109]. These faults are continued in his journalism. Dr Perry stated that Mr Kahn completely misreported two alleged cases of TB transmission (p 267). Mr Scurr was surprised to find that Mr Kahn not only claimed credit for DVT-related research that was not his but also purported to summarise the findings which, at the time, were not known (p 283). We acknowledge that some of the professionally written material promulgated under the aegis of the Aviation Health Institute is very helpful. However, we have been concerned at the confused thinking, lack of substance and erroneous statements in some of the other material presented to us and the public by Mr Kahn, the Institute's founder director. In spite of his evident enthusiasm for his cause, sadly we have not found him to be a reliable source of scientific and medical information.

Box 6

Examples of headlines



Health risks to air passengers bring calls for stronger warnings
Guardian - 3 May 2000

What that holiday flight really does to your body
Daily Mail - 30 May 2000

How safe is Airplane Air?
Wall Street Journal - 9 June 2000

Inquiry into blood clot danger for air travellers
Independent on Sunday - 2 July 2000

Fasten your seatbelts - it could be a sickly ride
Mail on Sunday - 2 July 2000

Are planes bad for you?
Daily Telegraph - 3 July 2000



The sky high cancer risk (the flight path of a 747 to Japan is a trip through radiation hell)
Guardian - 11 May 2000

Long-haul passengers pass out from "oxygen shortage"
Sunday Times - 14 May 2000

Flying can prove fatal in economy class
Independent on Sunday - 28 May 2000

It's high flyers who may be laid low - a survey claims airlines are neglecting in-flight health
Daily Telegraph - 22 June 2000


8.40 There is much more information available for health professionals. As indicated by the references throughout the evidence submitted to us (reproduced in Volume II of this Report), much of this is of a highly specialised nature. Being also mainly journal-based, such material is of limited use to busy general practitioners and practice nurses for quick reference.

8.41 Doctors and nurses in general practice may only rarely be asked to give an opinion on fitness to fly and, if asked, they need to have appropriate reference material readily to hand. We were surprised to learn that the current edition of the DoH book Health Information for Overseas Travel aimed at health professionals did not contain information on medical considerations for travel and on the significance of pre-existing medical conditions (Q 26), and we were pleased to find that this was being remedied in a revised edition already in preparation, and the Minister confirmed that it would, in particular, deal with deep vein thrombosis and immobility (Q 533). We recommend that DoH monitor the use of the revised Health Information for Overseas Travel to ensure that, with further additions and amendments as necessary, the publication provides the user-friendly authoritative information source that is needed by health professionals.

8.42 Other broad-ranging guidance is currently rather limited. Two UK publications to which our attention was drawn are Aviation Medicine[110] and the chapter on aerospace medicine in the Oxford Textbook of Medicine[111]. However, both of these are essentially scientific texts for doctors with special interests in aviation medicine rather than practical guides for general practitioners. A better model, because it is designed for doctors who deal with passengers rather than with aircrew, is the American Medical Guidelines for Air Travel[112].

8.43 Into this gap, the airlines have themselves placed material on fitness to fly and related courses for health professionals (QQ 315 & 317), free of charge (Q 321), and they acknowledged the demand for such guidance (QQ 315 & 317). During the preparation of this Report, British Airways opened its new health web site[113], to which its useful guide for doctors, Your Patient and Air Travel, has been transferred. The Aviation Health Institute has also promulgated Contra-indications to Air Travel: Guide for GPs[114].

101   See paragraph 8.3. Back

102   Although, commendably, British Airways was actively and materially supporting research into DVT (Q 304) Back

103   Irvine D and Davies D M (1999), Aviation, Space, and Environmental Medicine; 70:548-555, as cited by Varig (p 288) Back

104   CAA also publishes a leaflet, Travelling Safely, but dealing only with safety issues.  Back

105   As noted in paragraph 8.26, revisions are in prospect. Back

106 Back

107   We have been very conscious of this responsibility in framing our Report. Back

108   3rd Report, Session 1999-2000, HL Paper 38. Back

109   The text of which is reproduced as a footnote to Q 128. Back

110   3rd edition, British Medical Association Publishing Group, 1993. Back

111   3rd edition, Oxford University Press, 1996. Back

112   Aerospace Medical Association, Alexandria, Virginia USA, 1997. Back

113 Back

114   Published in General Practitioner, 23 June 2000 Back

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