People are looking to fly, but aviation medicine falls short

This post is cross-posted on CanLii.

A significant danger when governing safety-sensitive occupations is lapsing into anecdotal evidentiary practises to justify rigid rules. The danger inherent in anecdotes is their subjectivity, which is often clothed in the guise of fact: a rule’s legitimacy depends on the safety that it provides, which in turn must relate to an objective measurement. Absent that data, the rule exists with only putative purpose. We fall onto a host of fallacies, where personal opinion and lack of evidence create circular reasoning or, worse, a series of false dilemmas all in the name of safety. Rich democracies that tout the strength of their legal systems should, however, be better able to capture nuance.

Few fields better exemplify these ills than Canadian aviation medicine’s approach to mental health. The International Civil Aviation Organization (ICAO) points this criticism up in its Manual of Civil Aviation Medicine:

Aeromedical policy and individual decisions are often based on expert opinion, (‘level 5’ evidence) (13). Although expert opinion may be evidence-based, such an approach (which may also be termed ‘eminence-based’) is not as reliable as one that uses higher levels of evidence. However, expert opinion is often the easiest (quickest and least costly) to implement and may, therefore, be an attractive option for regulatory authorities. If a medical expert has experience in aviation medicine and their own specialty, such an opinion may be of great value (it may be the only possible approach for uncommon conditions), but often opinions vary greatly between experts presented with similar cases.


A quick review of a couple aviation medicine standards reveals that its approach to mental health is generally prohibitive: aviation’s traditional understanding of mental health problems is that any grey or black mark on a record disqualifies an aspiring pilot. This position has been somewhat alleviated in recent years, but civil aviation remains marred by what appears to be the illusion of certainty, which illusion potentially entails legal consequences for aviators and their medical professionals. A more permissive approach to mental health in civil aviation medicine may help resolve this tension.

To be clear: this problem is not one of regulatory inflexibility. Canada’s regulations and ICAO’s suggestions all allow a degree of flexibility commensurate with aviation safety. The problem is that, in the quest for aviation safety, Canada’s regulators have applied flexible standards in such a rigorous way that they risk violating human rights.

Evidence of a problem

In civil aviation medicine’s own words

ICAO’s Manual of Civil Aviation Medicine declares that:

Any mental condition which the applicant experiences or has experienced in the past must be assessed to ascertain the associated functional deficit. The examiner must also consider the risk of recurrence of any disabling psychiatric condition. Furthermore, many psychiatric conditions exist co-morbidly with other psychiatric conditions and particularly with abuse or misuse of psychoactive substances. The examiner must also be aware that, although the psychiatric condition may have responded well to treatment, the demands of the aviation environment are such that virtually any decrement in cognitive ability may have significant consequences.


This description adequately summarizes the conditions for obtaining a mental health clearance to fly. It also posits slippery slope logic and extends scientific data established by inference (i.e., studies of a cross-section of the population) to presumptive application in each case.

These sins are repeated with vigour in Transport Canada’s Handbook for Civil Aviation Medical Examiners. Anxiety and depression are presumptively banned for flight safety, with a policy that allows for individual examination. The Handbook, moreover, makes clear that Canada’s aviation medicine regulators have seen their hands forced to open their field of view up regarding neurological concerns:

The Canadian Charter of Rights and Freedoms which was enacted in 1982 has a number of human rights provisions, one of which states that “no person shall be discriminated against on the basis of disability”. Given this constitutional background there have been an increasing number of challenges in the Courts and Human Rights Tribunals on refusals to medically certify applicants with neurological disorders. Aeromedical “unfit” assessments must therefore be based on current scientific “state of the art” knowledge.


Note, however, that this opening is created for neurological conditions, not psychological states: civil aviation medicine, perhaps mirroring aviation more generally, focuses on the physically demonstrable. Intangible mental states are still expressly forbidden in the Handbook, although a policy exists to allow some leeway for personal circumstances. We may deduce that this policy exists as some response to human rights concerns.

These responses fall short of the mark because two standards exist in aviation medicine. The first and most accessible standard is inductive: data is selected and produced to inductively justify a prohibition; a second nuanced standard requires deductive assessment of each patient’s actual condition.

These standards are meant to be complementary, but they carry the potential for uneven, anecdotal application reflective of personal opinion rather than established fact.

The problem, plainly

This difference applies David Hume’s Problem of Induction to a safety and human rights context. Hume describes his problem:

Shou’d it be said, that we have experience, that the same power continues united with the same object, and that like objects are endow’d with like powers, I wou’d renew my question, Why from this experience we form any conclusion beyond those past instances, of which we have had experience? If you answer this question in the same manner as the preceding, your answer gives still occasion to a new question of the same kind, even in infinitum; which clearly proves, that the foregoing reasoning had no just foundation.

A Treatise of Human Nature,

The first sentence of this description captures aviation medicine’s default position, the position of scientists intent on finding the most general rule to guarantee safety. Canadian aviation medicine, in fact, announces its desire to behave inductively in Transport Canada’s policy regarding mental health: ‘Each disposition decision is unique in its own way and cannot be cited as the “rule” for the next case. Precedence is set with each case but cannot be used precisely to measure the merits of the next case’ [sic]. This instruction, though a clear statement of deduction when considered in vacuo, means that medically observed trends apply over each case. The deductive process only begins once the inductive fantasy (see my other work on this subject) has run its course.

The problem, compounded

Courts, whose role at common law is often framed as the guardian of rights and freedoms, have generally gone along with Transport Canada’s decisions. The executive branch is afforded wide discretion in these matters and must only show that its policies and decisions are reasonable.

Justice Hughes of Canada’s Federal Court, put the matter plainly in Corneil v Canada. A man with obsessive compulsive disorder decided to obtain a pilot’s licence. He submitted to a Canadian aviation medical examiner and informed the examiner that he was taking four medication to control his compulsions. He was denied medical certification because his taking four psychotropic medications simultaneously presented a risk to air safety. The reasoning behind this decision is that psychotropic medications alter perception and emotions, which alterations inherently affect a person’s fitness to fly. Corneil took this decision on appeal and lost; the Court was implicated on judicial review of the appeal decision, where Corneil claimed that his Charter right to equality and his Canadian Human Rights Act right to non-discriminatory treatment were violated. Justice Hughes deferred to the appeal tribunals’ aeronautical expertise: he evaluated whether the denied appeals were reasonable.

After reviewing the case, Justice Hughes found Corneil unfit to hold a pilot’s license, but the Justice’s decision perfectly illustrated the problem of induction. A finding of reasonableness examines an inferior tribunal’s legal reasoning outside of its area of expertise and its disposition of the evidence based on its reasoning. Justice Hughes recapitulated part of the evidence:

I have not reproduced all of the relevant evidence but what I have set out gives a flavour as to what the one-member Tribunal had to consider and the three-member Tribunal had to review. This evidence is, by its nature, somewhat speculative; the Applicant has not had a problem — yet — and his medical expert says, in the double negative, that there is no evidence that he cannot. The Minister’s medical evidence is to the effect that, while one cannot say for certain, the more drugs that are being taken, the more one has to be cautious as to their effect, particularly with respect to sedating drugs.

Para. 48

Both sides speculated as to the effects of the four medications that Corneil was taking. Neither party, however, seems to have asked a more fundamental question: what can Mr. Corneil do? Put differently, the parties were, perhaps by the nature of the rules they were bound to apply, debating different inductive fantasies based on evidence derived from induction. The deductive exercise of determining Mr. Corneil’s actual abilities was not conducted, although Mr. Corneil did request this relief from Justice Hughes. The judge cited the Meiorin test, which allows a court to determine whether an employer has a veritable reason to discriminate against employees, in analogy:

In brief, an employer, and here by analogy, the Minister of Transport, can choose its purpose or goal as long as it is done in good faith and legitimately. If the policy or practice is reasonably necessary to an appropriate purpose or goal, and accommodation short of undue hardship has been incorporated into the standard, the fact that some classes of persons are excluded does not amount to discrimination.

In the present case, the Act and Regulations are directed to air safety. Medical fitness of a pilot is required. Discretion is given to the Minister, in the case of a disability, to grant a licence when air safety is not compromised.

Paras. 51-2

The judicial inquiry is, in short, precluded, according to Justice Hughes, once the executive branch has earnestly chosen its policy or practice, so long as that policy is ‘reasonably necessary’. If medical opinion applied to individuals gives a whiff of intolerable risk, the individual is not entitled to fly a plane.

Reversing the onus in aviation medicine

The current judicially sanctioned system places a lot of emphasis upon the general observations of medical researchers, while placing the individual applicant’s abilities on a lower order. This pattern is, as I’ve suggested, flawed. It privileges opinions that are, by their definition and intent, completely disinterested in the applicant. The applicant is thus forced to prove themselves capable, but such proof may not be considered if a judge’s first reference is evidence derived from induction.

Reversing this onus, however, effectively resolves the problem: all applicants for an aviation medical certification must prove their ability to meet requirements necessary for certification. This approach frames safety concerns in terms of aptitude, which may be deduced from interaction with the applicant. Civil aviation medical examiners’ authority in this regard is further asserted because they are best placed to evaluate their patients. Transport Canada’s central aviation medical branch reviews decisions, but it faces the uphill battle of disproving the initial examiner’s deductive claims.

This approach would be more commensurate with the Supreme Court’s test in Meiorin, which then-Justice McLachlin delivered on behalf of a unanimous bench:

I propose the following three-step test for determining whether a prima facie discriminatory standard is a BFOR.  An employer may justify the impugned standard by establishing on the balance of probabilities:

(1)   that the employer adopted the standard for a purpose rationally connected to the performance of the job;

(2)   that the employer adopted the particular standard in an honest and good faith belief that it was necessary to the fulfilment of that legitimate work-related purpose; and

(3)   that the standard is reasonably necessary to the accomplishment of that legitimate work-related purpose.  To show that the standard is reasonably necessary, it must be demonstrated that it is impossible to accommodate individual employees sharing the characteristics of the claimant without imposing undue hardship upon the employer.

This approach is premised on the need to develop standards that accommodate the potential contributions of all employees in so far as this can be done without undue hardship to the employer. Standards may adversely affect members of a particular group, to be sure.

Paras. 54-5

Assuming that Meiorin may be made to apply to aviation medicine, Justice McLachlin’s test contains a compelling argument for the reversed onus. Transport Canada already admits to a need for additional pilots: Canadian air operators are facing a shortage of qualified aviators. The policy regarding aviation and mental health adverts to this shortage when discussing psychotropic medication:

There is an increasing consensus of medical opinion that it is possible to allow the use of these medications in aircrew, in circumstances that would not compromise flight safety or operational effectiveness, and, on the positive side, would allow the preservation of trained aircrew resources.

The potential contributions of all those interested in aviation can be valorized so long as each individual demonstrates that they are able to safely take part in the desired activity.

Justice McLachlin’s third criteria is the clincher in any argument for a reverse onus. The government must demonstrate that the current aviation medical regime is the only means of accommodating applicants for medical authorization. If another reasonable alternative exists, the Meiorin test requires its application. Justice McLachlin also anticipated objections to her test:

Courts and tribunals should be sensitive to the various ways in which individual capabilities may be accommodated. Apart from individual testing to determine whether the person has the aptitude or qualification that is necessary to perform the work, the possibility that there may be different ways to perform the job while still accomplishing the employer’s legitimate work-related purpose should be considered in appropriate cases.  The skills, capabilities and potential contributions of the individual claimant and others like him or her must be respected as much as possible.  Employers, courts and tribunals should be innovative yet practical when considering how this may best be done in particular circumstances.

Para. 64

The reversed onus for which I have argued places the emphasis where Justice McLachlin wants it to belong: on the individual facing discrimination. If Justice Hughes pushed his analysis a touch further, he may have extracted this lesson from Meiorin and applied it analogously to Transport Canada’s regulation of aviation medicine.

Justice LeBlanc correctly applied the Meiorin test in Walsh v Canada, where a mariner was denied a marine medical certificate because he suffered from alcohol dependency and depression. This case was a review of the Canadian Human Rights Commission’s decision to refuse (for a second time–the first decision in this case was rendered four months before Justice Hughes’ decision in Corneil) prosecuting the mariner’s case before the Canadian Human Rights Tribunal. Justice LeBlanc viewed Transport Canada’s blanket denial with suspicion because he identified other accommodations that could allow the mariner to exercise his profession. The Justice cited Justice McLachlin’s decision in Meiorin to order a third review by the Human Rights Commission:

Also, as the Supreme Court of Canada pointed out in Meiorin, courts and tribunals “should be sensitive to the various ways in which individual capabilities may be accommodated” (Meiorin, at para 64). Although I appreciate the fact that when it comes to seafarers, Transport Canada acts as a regulator, not as an actual employer, and that, therefore, there are some limits to its duty to accommodate, the Commission, in the Supplementary Investigation Report, appears to recognize that part of Transport Canada’s role in that regard is to “possibly identify potential accommodations measures an applicant may require” (Supplementary Investigation Report, at para 48). It seems that performing “No Lone Watchkeeping” duties under the supervision of a ship officer, as proposed by the Applicant (Supplementary Investigation Report, at para 27) could alleviate the safety concerns Transport Canada has regarding this accommodation option by making sure that there is no ambiguity for the crew and the public as to who is the person ultimately in charge of giving instructions. I take it that this option could be in place until the end of the policy’s two-year monitoring period and subject to the policy’s quarterly abstinence reports. There is no evidence before me that an employer would not be amenable to such an arrangement, be it for health, safety or costs concerns. However, there is no discussion in the Commission’s Supplementary Investigation Report as to whether it would have been impossible to accommodate the Applicant in this fashion in May 2012.

Para. 53

Justice LeBlanc’s reasoning applies a strict view of the Meiorin test’s third criteria to Transport Canada medical decisions and to human rights review of Transport Canada’s actions and policies: neither Transport Canada nor the Canadian Human Rights Commission can use broad medical observations to create a rule of general application. Government agencies must always inquire into an applicant’s specific circumstances.

Corneil has received little judicial commentary. Judges prefer Justice LeBlanc’s approach to reviewing medical clearances. The sticking point in these cases is, as I have suggested above, that administrative decision-makers must have regard for ‘obviously crucial evidence’ (Houle v Canada, para. 101), which evidence relies on deductive inquiry rather than an inductive application of broad medical observations. Another mariner case, Houle v Canada, upheld the general rule, which promotes reversing Transport Canada’s current onus:

This approach, mainly focused on the general unfitness for work at sea of people who, like the applicant, are suffering from mental or behavioral disorders, contrasts with the standards of the normative framework which is required at Transport Canada. These standards, while being focused, as they should be, on maintaining safety at sea, allow, as we have seen, for a degree of flexibility in their interpretation, provide guidance for physicians called upon to interpret them and make the “individual features” of the common medical condition of the seafarer being examined the heart of the assessment of his or her fitness for working at sea. Also, and above all, these standards, unlike the Physician’s Guide, recognize that a seafarer afflicted with mental or behavioural disorders may still be fit, with or without limitations, for service at sea.

Para. 112

The same judicial reasoning may be directly applied to Transport Canada’s civil aviation medical certification process. The current double standard forces applicants to justify their condition when Transport Canada’s objective in fact looks to assess, in positive terms, whether all flight personnel are medically fit to fly, regardless of how their personal foibles and conditions are categorized.

Making aviation medicine more responsive

When the onus is reversed, Canadian aviation medicine better achieves the twin goals of flight safety and compliance with Canadian human rights standards with respect to mental health. Safety is maintained by first-order investigation of mental health concerns, including potentially dangerous treatment options. The investigation is focused on a doctor-patient interaction, which ensures that the patient’s actual circumstances and disposition are taken into account. The process is, of course, more resource-intensive, but the administration of aviation licensing is already resource-intensive: the existing infrastructure carries the load while allowing more Canadians to become safely involved in this exciting world.