Commentary: The Age 60 Rule as Protection Against Pilot Medical Incapacitation: Is It Still Valid?

Victor S.B. Jorden, M.D., M.P.H.*, and Susan P. Baker, M.P.H^§.

* Resident in Preventive Medicine, New Jersey Department of Health and Senior Services

§ Professor, Department of Health Policy and Management, The Johns Hopkins School of Public Health

As the conclusion of the 20^th century grows near, increasing numbers of traditional, arbitrary, and prejudicial barriers to occupational practice are being struck down. One of the most important of these barriers is age. In more and more professions, mandatory retirement ages are being banned, or at the very least, the rationale for a mandatory retirement age is being reviewed with careful scrutiny. One field that has sustained its mandatory retirement age, however, is commercial aviation. The Federal Aviation Administration Code states that all commercial airliner pilots (Part 121), as well as many scheduled commuter pilots (Part 135), must retire upon reaching the age of 60 regardless of their state of health and their ability to function as an aviator.¹

The Federal Aviation Administration (FAA) has specified three major concerns in permitting aviators over the age of 60 to continue as pilot-in-command in commercial aviation: reduced sensory acuities (visual and auditory), decreased pilot proficiency (including such parameters as reaction time and ability to function under stress), and most of all, increased risk of pilot incapacity due to medical disaster. The FAA has repeatedly concluded, in spite of contradictory evidence, that the risk of sudden medical incapacitation becomes unacceptably high once an individual turns 60. Additionally, the FAA asserts that the reasonable prediction of which pilots over the age of 60 are at greatest risk for incapacitating events is not possible.

Is the FAA’s logic reasonable, especially as we enter a millenium in which the average life span is greater than ever before, and the average health of persons 60 years or greater is better than it has ever been before? ² Are the FAA’s arguments based on reason, or are they a vestige of age discrimination that has managed to survive such legislative efforts as the Age Discrimination in Employment Act? Considering the amazing technological advances of recent decades, is the FAA’s premise of the lack of predictability of heart disease still valid? This discussion will analyze the historical perspective of the Age 60 Rule, the scientific basis, if any, for utilization of this retirement age, and consideration of whether this arbitrary guideline should be continued.

Brief History of the Age 60 Rule

The Federal Aviation Act of 1958 gave the FAA the authority to pronounce "regulations in the interest of safety for the …periods of service of airmen." Indeed, the legislature not only allowed, but required, the Administrator of the FAA to regulate "in a way that best tends to reduce or eliminate the possibility or recurrence of accidents in air transportation." The agency initiated the Age 60 Rule in 1959, citing the following reasoning:

"…there is a progressive deterioration of certain important physiological and psychological functions with age, that significant medical defects attributable to this degenerative process occur at an increasing rate as age increases, and that sudden incapacity due to such medical defects becomes more frequent in any group reaching age 60." ³

 

One of the FAA’s primary fears was that the pilot-in-command of a commercial airliner would suffer a cataclysmic cardiovascular event during a flight, thus potentially leaving the aircraft and all the occupants therein at the hands of a less experienced first officer during a critical juncture. The FAA admitted even in 1959 that not all pilots over the age of 60 were at risk for such disastrous in-flight events. However, the prevailing premise at the time, and the one on which the rule was based, was that the existing medical technology lacked sufficient sophistication to determine exactly which pilots were at high or low risk.

To bolster support for the Age 60 Rule, the FAA also cited other issues to legitimize the regulation. Most prominent among these issues was the apprehension that the natural aging process, accelerated once the age of 60 was attained, resulted in reduced pilot capability as follows:

"loss of ability to perform highly skilled tasks rapidly, to resist fatigue, to maintain physical stamina, to perform effectively in a complex and stressful environment, to apply experience, judgement, and reasoning rapidly in new, changing, and emergency situations, and to learn new techniques, skills, and procedures." ³

However, in response to challenges to the Age 60 Rule that have arisen over the last 40 years, the fear of precipitous medical incapacitation has been cited over and over as the key reason for the dictum.

As the result of pilots’ advocacy efforts, the FAA has considered rescinding the Age 60 limitation at several times, including the early 1960’s, 1970, 1979, and 1982.⁴ At least one reevaluation was initiated by an act of Congress (1979). On all of these occasions, the agency’s final decision was to continue the Age 60 restriction, because of the continued inability to determine which pilots were at risk for an in-flight disaster. The FAA has continued to embrace the regulation in the last two decades, even in the face of a 1981 National Institutes of Health/ National Institute on Aging Report stating that medical evidence for the Age 60 Rule was absent.⁵ If any change has occurred in the FAA’s view of the Age 60 Rule, it has been in greater favor of the constraint, since the agency expanded the scope of the restriction by including certain commuter pilots (Part 135) under its jurisdiction as of 1995.⁶

The Age 60 Rule has been challenged through litigation on several occasions; some of these efforts have been assisted by the Professional Pilots Federation, an aviators’ advocacy group devoted to the rule’s dissolution. One major case was brought in 1993, when the Professional Pilots Federation, et al., sued the FAA to enable plaintiff pilots to continue as commercial pilots-in-command after turning 60 years of age.⁴ Notable in this lawsuit was the pilots’ citation of a series of studies (the "Hilton Report") commissioned by the FAA itself and performed by Hilton Systems, Inc. The Hilton report, based on an analysis of aviation accidents and pilot age, determined that there was actually a decreased trend of aviation mishaps as pilots approached the age of 60.⁷ The researchers admitted that the findings of the study might have been based, in part, on the rigorous medical screening and "weeding-out" of many pilots prior to their attaining the age of 60. In spite of this weakness, the report was considered by many in both the aviation and aerospace medicine communities as critical evidence invalidating the Age 60 Rule.⁸ However, the case was found in the FAA’s favor, and the Age 60 Rule remained in force.

A more recent suit was decided in 1997 in the case of Coupe v. Federal Express Corporation. Robert Coupe, a Federal Express pilot, was apprised that he would have to either retire or accept a lower paying flight engineer position when he reached his 60^th birthday, to comply with the FAA Age 60 Rule; this form of demotion is common, since unlike pilots-in-command, commercial flight engineers are not constrained by the rule. Coupe sued, citing primarily the Age Discrimination in Employment Act (ADEA) of 1967, but the FAA prevailed.⁹ The United States Ninth Circuit Court of Appeals affirmed the decision of the lower federal district court: the ADEA was held to be subordinate to the necessary occupational qualifications for the profession under consideration, and the FAA’s rationale for the Age 60 Rule, meant to promote public safety, could be interpreted as reasonable.¹⁰

Scientific Background

Several research issues have evolved as part of the effort to define the validity of the Age 60 Rule as it applies to sudden medical incapacitation. How often does in-flight medical incapacitation of the pilot occur, and how have passengers been impacted by pilot incapacitations? How does age impact on the risk of incapacitation? Finally, what technology exists that may determine which pilots are at moderate or high risk for in-flight disasters? As all these questions are answered, it should be possible to estimate the true legitimacy of the Age 60 Rule.

The occurrence of sudden medical incapacitation among pilots has been examined on various occasions using domestic data, with special regard to its association with advanced age. Buley studied in-flight disasters for the years 1961-1966; his data showed that the average age for incapacitations among licensed pilots was between 43 and 46 years, a finding that reflected the age distribution of pilots.¹¹ Two studies published in 1971 indicated that sudden incapacitations occurred very rarely (2-25/100,000 pilots per year), but the rate increased significantly with age.^{12, 13} This association between increasing age and an increasing accident rate was also found to exist in a 1977 study by Booze; however, in a review addressing these types of investigations, Booze’s study was considered to be methodologically flawed.^{14, 15}

Mohler and Booze determined in a 1978 study that pilots had fatal heart attacks in 13 of 1404 general aviation crashes, for the time period of 1974-75 inclusive.¹⁶ The pilots experiencing these adverse events ranged in age from 33-68 years, with a mean of only 52 years. The authors of that research concluded that although the potential of adverse medical event may increase with age, there is clearly no guarantee that restricting commercial pilots to age less than 60 negates the possibility of such an event occurring.

In 1989 Booze studied National Transportation Safety Board (NTSB) data from 1975-1982, and determined that 3 crashes in 1000, or 15 of 1000 fatal crashes, were attributable to all causes of pilot medical incapacitation; this statistic includes all types of aviation, not just commercial.¹⁷ The data suggested that the likelihood of incapacitation increased with age, but the risk of incapacitation was lower overall than would be seen among the general population. These findings confirmed earlier research reported by the same author examining the relationship between age, occupation, and accidents.¹⁴ This earlier study had led Booze to conclude that occupational accidents were rarer among pilots than one would expect in the general population. An additional important finding was that a recent FAA certifying medical exam was not associated with a lower risk of accidents. Thus, the present FAA medical certification, although clearly a reasonable screen for medical problems by virtue of the very low incidence of in-flight disasters, does not guarantee pilot health at ages less than 60. Furthermore, pilots at any age are at lower risk for accidents than their similarly aged counterparts in several other professions, including medicine. Thus, the probability of a neurosurgeon collapsing during the clipping of a cerebral aneurysm may be significantly greater than the risk of a similarly aged pilot collapsing at the controls of a commercial aircraft.

A longitudinal study presently in progress may help to definitively resolve the issue of hidden cardiac risks among older pilots. A longevity and survival analysis for a cohort of retired airline pilots is being conducted under the aegis of Office of Aviation Medicine, Aircraft Accident Research Team, within the FAA Office of Aviation Medicine, Civil Aeronautical Institute.¹⁸ This investigation is following the survival of retired pilots, with determination of their risk for sudden events during the years they would have been permitted to fly had they not been forced to retire at age 60. Such research should supplement the older data from studies such as the "1,000 Aviators Study," which indicated that former military pilots died more rarely from cardiac causes than matched non-pilots.¹⁹ Naturally, the bias in such longitudinal studies would arise from the stresses of retirement greatly differing from those associated with flying a commercial aircraft, since these stresses may be a critical factor in the progression of cardiac disease. However, considering that many pilots continue flying in other non-commercial venues after age 60, the confounder of occupational stress may be epidemiological and statistically manageable.

In summary, aircrew in-flight medical disasters are extremely rare events. These events appear to occur more frequently in older than younger pilots, but have been found to affect aviators across a wide spectrum of ages. The low incidence of these events leads to the conclusion that although the present medical screening system is adequate, it is not infallibly predictive. Interestingly, incapacitations have caused no injuries or deaths in individuals other the incapacitation victims themselves, whether the incidents occurred in commercial or other types of aviation. However, a review of the FAA Adverse Incident Data System reveals multiple incapacitation reports describing passengers taking control of the general aviation aircraft, and commercial first officers landing airliners with the assistance of flight attendants. An in-flight pilot incapacitation, while never having affected hundreds of passengers at a time, clearly has the capacity to do so.

Medical Risk Assessment

The Age 60 Rule was written 40 years ago in 1959. At that time, the FAA’s policy was predicated on an existing medical technology that was incapable of determining which pilots were at high risk for sudden incapacitation. Since that time, despite the tremendous advances seen in medical technology, the FAA’s premise of lack of predictability has not changed. Many non-invasive tests such as exercise stress tests, as well as minimally invasive assessments such as blood lipid levels and stress-thallium tests, have been routinely used to stratify cardiac risk since as early as the 1980s.²⁰ However, even the Class 1 medical exam, the FAA’s highest tier of scrutiny and the one used to medically certify commercial aviators, includes only an electrocardiogram and not even a serum cholesterol level.²¹ The FAA clearly respects the prognostic value of more advanced technology such as stress tests, since such assessments are definitively required for the recertification of Class 3 airmen following a cardiac event.²² Why the FAA remains unaccepting of such technology as part of routine evaluation for class 1 airmen is unknown.

In addition to the screening modalities already discussed, such as stress tests and serum lipid profiles, two new tests are being evaluated for use in determining cardiac risk. Both of these are minimally invasive, easily performed blood tests. The measurement of C-reactive protein "would add greatly to the predictability of heart attacks in people not normally seen to be at risk."²³ Such a laboratory evaluation appears to be precisely the assessment needed by the FAA to identify pilots with adverse potential. An additional test under study is serum insulin level.²⁴ Researchers found that a high blood insulin level "was superior to measuring other risk factors in determining whether individuals would have heart attacks."

Even if these laboratory evaluations are not acceptable to the FAA, surely the standard American Heart Association First Heart Attack Risk Test should be. The assessment, which could easily be incorporated into the medical history taken by the Aerospace Medical Examiner, combines nine risk factors including age, family history, other illnesses such as diabetes and hypertension, and serum cholesterol level; the levels of these factors are then combined into a numerical index of risk.²⁵ Although "age greater than 54" was the single most heavily weighted contributory factor, the assessment emphasizes that lifestyle issues and the presence of medical risk factors impact heavily upon the risk of first heart attack.

The FAA maintains that risk stratification using present medical knowledge and technology is not sufficient. However, a study that the FAA commissioned through its Civil Aeronautic Institute, examining 44 in-flight incapacitations occurring from 1982 to 1991, determined that only one pilot in five had an "antecedent condition," suggesting that screening, at least based on history alone, may not be a reasonable predictor.²⁶ Incredibly, however, the FAA itself continues to rely primarily on histories attained by its medical examiners to certify (or not certify) pilots. Thus, by virtue of the FAA’s own study, risk assessment should be modernized to include newer modalities, since the medical history alone is clearly not adequate.

The FAA has considered the use of screening exercise stress tests, but has rejected them citing low predictive value as the reason.²⁷ Yet, the same regulating body continues to believe that the milestone of age 60 yields better predictive value. The evidence is clear from the cardiology community that the risk of an incapacitating event may be stratified, thus permitting the screening out of high and even intermediate risk pilots from Parts 121 and 135 service. Why the FAA has proven so resistant to the inclusion of newer modalities into its certifying examinations remains unclear.

Conclusions

The aging process is being studied in greater depth and with more profound interest than ever before. One of the most important and universally accepted tenets that can be made about this process is that we do not all age uniformly.²⁸ The function of our bodies changes at different rates, and as a result many persons enjoy excellent health into their sixth, if not later decades. Certainly, this prolonged state of sound health should be noted among airline pilots, who have been described as "the healthiest group in the world."²⁹

Does the risk of in-flight pilot incapacitation increase with age? Data are contradictory: some research, such as the Hilton Report, indicates no increased accident rate with advancing age, while several aforementioned earlier studies link older pilots with increasing rates of incapacitations. Significant strides have been made in the diagnosis and treatment of chronic conditions often preceding cardiac events, such as hypertension and hypercholesterolemia, and such technology may be creating a much healthier group of older pilots than ever seen previously. Perhaps the only reasonable statement that may be asserted about the association between age and incapacitation is that the dynamics of the relationship are changing, and that older data may be invalid due to medical advances.

Whatever the relationship between aging and incapacitation, the low yet disturbing frequency of incapacitating events that have been documented to occur in pilots substantially younger than 60 cannot be ignored. Incredibly, the average age for in-flight impairment in one study cited above was approximately 45 years, with events occurring in aviators as young as 33 years. Clearly, the Age 60 Rule failed to protect the flying public from any hazards related to these pilot events. The numerous incapacitations suffered by relatively young pilots indicate that the antiquated certification system presently in use has serious deficiencies, regardless of whatever scientific validity may exist for forced retirement at 60.

The draconian Age 60 Rule is completely effective at removing all pilots at risk for incapacitation who are over the age of 60, by preventing them from flying commercially at all. However, the combination of present screening standards, which include the Age 60 Rule, are obviously not completely efficacious at removing all pilots at risk. Medical technology has advanced to a point where the reasonable screening of pilots at risk for adverse events is a reality, and assessment methods continue to improve rapidly. Such screening may be accomplished non-invasively and at acceptable cost. The FAA is clearly accepting of such technology, since such non-invasive testing is required for class 3 airmen (private pilots) who have suffered cardiac events and wish to return to flying.

In light of this analysis, the Age 60 rule is no longer valid as a measure to prevent in-flight medical incapacitation. Such a conclusion was reached years ago among the European Union (12 nations), in Australia, and other international venues where aviators over the age of 60 may continue as pilot-in-command. The overall rarity of incapacitations, general good health of pilots, and the safety net of medical risk stratification and screening make the Age 60 Rule nothing more than an anachronism in 20^th century occupational health. The proposal of risk assessment as a substitute for the arbitrary retirement age of 60 for pilots is not new, yet today it carries greater validity than ever before.^{30, 31} Such screening would enhance aviation safety by not only properly screening out medically unsuitable pilots under the age of 60, but also by permitting aviation consumers to benefit from the most mature and experienced captains in the fleet who may be over the age of 60.³² Clearly, once modern risk assessment and medical screening have been appropriately incorporated into pilot certification, the benefits of having a captain over 60 will greatly exceed the risks.