5th September 2005

Long Haul Medical Issues

by Michelle Doherty -- Source: PIA Air Safety Publication

While pilots are often cited as having fitness and longevity levels that exceed those who work in non-flying professions, there are certain factors that have raised concerns in the past and need to be considered in the operation of long- haul flights. With modern aircraft promising to increase flight times still further, medical specialists are using previously gathered data in an attempt to foresee problems that may arise when flight times increase.

Over the years, one of the prime health concerns to those who fly regularly has centered on whether flight crew have an increased risk of cancer due to prolonged exposure to high doses of cosmic radiation. This has led to a number of studies into this matter including one carried out by the California Department of Health Services on Cabin crew, which found that there was a twofold increase in the risk of melanoma skin cancer and that breast cancer was 30% higher.

The World Health Organization (WHO) says that while airline crews are subjected to higher levels of naturally occurring radiation than the general public, levels are still low. Dr. Ian Perry, an aviation medical expert who sits on a number of advisory panels, believes that there is too much blame placed on flying and that such illnesses may have more to do with airline crew's "lifestyle and irregular diet over the years." He also says that crews go to more exotic locations and are therefore exposed more frequently to sunlight which in turn means they have a higher risk of skin cancer.

At a seminar on The Aeromedical Challenges of Ultra-long Haul Flying held at the Royal Aeronautical Society (RAes) in London in April 2004, Dr. Michael Bagshaw of British Airways (BA) presented a paper on cosmic radiation. Bagshaw discussed how at low altitudes we are protected from cosmic radiation by the Earth's magnetic field. The area over the equator enjoys the greatest protection with zero protection offered over the geomagnetic poles and - somewhat anomalously - reduced levels of protection over an area in the South Atlantic. Air travel at altitude can take us beyond this protective 'blanket' and increases our exposure to cosmic radiation. With ULH flights setting to favor the use of polar routes in travel, it is clear that exposure on these flights will be even greater.

We are all exposed to 'background' radiation, measured in milliSieverts (mSv), throughout our daily lives and the International Radiological Protection Commission suggests a General Public limit dose of one mSv per year in excess of exposure to background levels. Placed in context, this equates to eight return transatlantic flights or five antipodean return flights in a year. Supersonic aircraft travel at higher altitude and as a result iust 100 hours per year of supersonic flight is enough to expose an individual to the recommended maximum dose. These guidelines are intended for passengers, for Cabin and Flight Crew, an occupational exposure limit of 20mSv per year is set instead.

Bagshaw explained how radiation exposure is calculated by taking a flight, its profile and airports used and then measuring the altitude, latitude and longitude of the flight as well as other contributory factors - such as the solar cycle. This is generally carried out using a range of computer programmes specifically designed for this task. While there have been reports of increased risk during times of solar flare, cosmic radiations itself "is a fairly constant flux," says Bagshaw.

BA has carried out a number of studies into radiation levels in flight crew and continues to monitor this issue. In one such study, flight crew levels were measured against those recorded in people working in other areas of industry. While the maximum levels recorded in flight crew were almost equivalent to those seen in people working in the nuclear fuel industry, the statistical average fell well below this rate.

So how does the overall picture look? Between 1950 and 1992, BA monitored 6,209 pilots and 1,153 flight engineers comprising 143,500 person years of observation. The results were encouraging and revealed that life expectancy for long haul crew was four to five years better than that of the average recorded in members of the public - with short haul crew having an increased life expectancy of two to three years. Although radiation levels are known to present a heightened risk of leukaemia, they were found to be far less than expected in those studied - in fact there was no occupational increase in cancer levels, bar that of melanoma.

Fatigue

The effects of fatigue in flight crew have also been repeatedly flagged up as a health care issue by both the aviation medical professionals and pilots themselves. At the Royal Aeronautical Society seminar, Dr. Ian Hosegood of Emirates Airlines discussed how the airline is looking at this issue.

Also to be brought into use by Singapore Airlines and Canadian Airlines, the four-engine 313-seater aircraft has a range of 8,360 nm (16,000 km) and will enable the airline to extend its operations to the east and west coast of the USA although it is likely to be used on shorter routes initially.

According to Hosegood, "there has been scant data on the medical effects of flying over 14 hours with pilot fatigue having been traditionally viewed as an industrial issue." Hosegood says that for the first time, safety is going to be dependent on flight crew being well-rested and that a paradigm shift in how this matter is approached by regulators is needed as the existing "football team approach" will no longer suffice.

Emirates has been busy reviewing scientific literature on the effects of fatigue using in-house expertise on this matter as well as that of Qinetiq and Harvard University and a number of other organizations conducting research in this area. Within the aviation industry, information from the United Augmented Flight Study, NASA and DERA reports and the results of the Emirates Pilot Questionnaire was reviewed. ULR meetings and workshops provided another source of information particularly as did those held by the Flight Safety Foundation in recent years.

Alternative modelling is to be carried out and Hosegood said, "we need to work out how much sleep crew get and what it's worth - for example we know it's important that crew rest at circadian lows." It has been found that if a rest period is simply split down the middle, crew are often fatigued. Having two sleep opportunities should ensure that at least one is successfully used and this is also said to reduce crew anxiety. Other ways that Emirates is planning to tackle this matter include a "stepwise" increment in sector lengths whereby crew can become slowly accustomed to flying longer sectors, integration into the company Fatigue Risk Management Systems (FRMS) and light exposure - although this is still seen as a tricky thing to get right and may potentially cause more of a problem if done incorrectly.

Educating crew and management and carefully devising rosters is also a key step in improving matters. Flight crew, especially, need to be armed with the knowledge to make "tactical decisions" and devise personal strategies for ensuring they are as well rested as possible and that they look at factors such as exercise, diet and caffeine intake and have a strategic plan for each route.

With plans to eventually use two captains and two first officers on the planned long haul A340 flights, Emirates has initially approved the use of the "City Pair" system whereby crew fly out and back in single sectors. Various designs of crew rest facilities are being looked at for onboard the new aircraft. Flight crew will be segregated from cabin crew and considerations include: noise / vibration, temperature / humidity, bedding, ablutions and relaxation as well as full IFE facilities.

In further fatigue modelling, testing and validation, Emirates will be using data gathered from using wrist actometers such Actiwatch. This "watch like" device can be worn by pilots to test fatigue levels and can be plugged into a laptop computer where data - similar to that seen in an electro-cardiogram - is downloaded and analyzed.

Other ways in which fatigue will be measured include using electro-encephalograms (EEC) and electro-oculograms (EOG), and sleep logs as well getting crew to participate in Psychomotor Vigilance Tasks (PVT).

However, one of the onegoing issues, says Dr. Hosegood, is the recognition that everyone is different and with this in mind it is difficult to know whether to model on the average or the worst case. Another factor to be considered is integrating with current Flight Time Limitation (FTL) schemes.

Recognizing the risks posed by fatigue, a number of organizations have published advice on alertness management. In their Guide, the Air Transport Association provides basic information on the physiological causes of fatigue and also prescribes some preventive and operational fatigue countermeasures. As well as obvious measures such as developing good sleeping habits and trying to minimize sleep loss, there is information on strategies that actively reset the body's circadian clock. Operational countermeasures include increasing social interaction and conversation, taking exercise and also the use of caffeine during a flight.

The Guide also cites ajoint National Aeronautics and Space Administration (NASA) and Federal Aviation Administration (FAA) study in which crewmembers who were allowed to take planned naps showed better performance (34 percent) and higher physiological alertness (100 percent) during the last 90 minutes of flight than the control group crewrnembers who had not napped.

The FAA does not currently sanction this practice, but research is ongoing and there are always going to be opportunities for 'strategic naps' outside of the cockpit. Napping is the only operational countermeasure that addresses one of the major physiological causes of fatigue - the need for sleep - and reverses it. While other operational countermeasures primarily mask fatigue, naps actually reduce it.

BA, as with many airlines, takes flight crew fatigue extremely seriously and has been taking steps to address this issue. Representatives from the airline have attended a Fatigue Countermeasure course run by NASA and then devised a training module, which is given to all flight and cabin crew. Flight crew receive this as part of their annual refresher course in aviation medicine, and cabin crew as part of their Crew Resource Management (CRM) training. As well as classroom sessions, printed notes summarize what they have been taught and highlight details on topics such as sleep scheduling, good sleep habits and napping. Long-haul crew also receive "preventative and operational recommendations, individualized to the operations they are flying." This translates as route and time specific advice cards for every long-haul sector flown by British Airways developed from a concept pioneered by Airbus Industries.

Stress

Stress and fatigue can be closely related and there are a number of environmental issues that can contribute to the levels of nervous tension in flight crew. For example, with aircraft travelling at increasingly high speeds it is vital that pilots have a high degree of alertness and are able to concentrate for the long periods of time required. This is especially true in poor weather and night conditions where there is an increased risk of an accident as visual references are lost. During such difficult conditions, pilots need to be extra vigilant and ensure that flight instruments are accurately monitored and this is naturally very tiring.

On long haul operations, the design of the cockpit itself can be an important contributory factor when measuring stress and fatigue levels. As well as ease of instrument use, heating and ventilation are important in maintaining comfort levels thereby reducing stress and areas of distraction.

Altitude can cause stress, particularly below 5,000 feet as this is where the greatest atmospheric changes generally occur and flight crew can suffer from trapped gases within the body. Common health problems such as a common cold can cause significant ear and sinus discomfort during descent.

'Self-imposed' Stress

While fatigue may generally be the main cause of stress amongst the pilot community, the lifestyle itself has much to answer for. A long-haul pilot is less likely to have a stable home life and multiple marriages are common. With divorce and relationship problems being high on the list of life's stressful events, this is a factor that can push an indivdual to a high point of anxiety and potentially into alcohol and drug abuse.

Many flight crew indulge in activities that are not always conducive to promoting good health. These do not only have adverse effects on their physical and mental well-being but can also be a real threat to safety. An acronym often used to list these factors is DEATH which stands for "Drugs, exhaustion, alcohol, tobacco and hypoglycaemia."

Psychological Problems

While the vast majority of pilots are extremely competent people of sound mind, they are not immune to the psychological disorders anymore than any other sections of the working public. A pilot's flying life - especially when flying long-haul routes - can be very stressful and it is important that colleagues or line managers are able to quickly respond to warning signs of psychological distress.

A case of what can happen when these warning signs are not observed is that of Gamil el Batouti, relief pilot of Egyptair Flight 990 who was thought to have crashed the aircraft on purpose. Post accident reports indicate that Batouti may have been an "acute psychotic" and that there were numerous warning signs that should have been noted. He was said to have exhibited frequent mood changes and was argumentative and was also said to have been invoked in a number of high-risk activities.

In light of this tragic event, the US National Transportation Safety Board (NTSB) suggested that it might be prudent for the industry to introduce psychological profiling of pilots. This suggestion caused outrage amongst the US pilot population who thought it would be ineffective and an invasion of privacy.

Aerotoxic Syndrome

While rare, there have been various reports on crew suffering health problems due to cabin vapours caused by either leaking engine oil or faulty air conditioning units. Exposure to such fumes can cause symptoms that range from skin, nose, eye and respiratory irritation through to neurological dysfunction and chronic fatigue syndrome. Chris Winder, from the School of Safety Science at the University of New South Wales, Australia says that any aircraft that leaks oil can cause such problems and said this can include Boeing 757, Airbus A320, BAe146 and MD80 types. A recent report by the Australian Federation of Air Pilots, highlighted the problem and cited details from a number of recent surveys that revealed the extent of the problem.

One of the most recent of these was an analysis of 21 BAe146 pilots who had experienced diarrhoea, recurring headaches, and intolerance to certain types of food and alcohol as well as brain impairment. These toxic vapours are said to range from "light blue to a black cloud and can smell like strong blue cheese," according to members of a research project on this matter.

Deep Vein Thrombosis (DVT)

In recent years, Deep Vein Thrombosis (DVT) has received more coverage - at least in the popular media - than any other air travel related issues. Michael Reynolds has set up 'Airhealth.org', a non- profit-making organization dedicated to educating air travellers on the risks of DVT. Reynolds and his team are quick to point out that the popularly termed 'economy class syndrome' is a condition which has the potential to affect all air travellers, pilots included. Quoting Dr. David McKenas, medical director at American Airlines, the website states that 'the most common causes of sudden pilot incapacitation are cardiac arrest, arrhythmia, and fainting', all of which are often caused by a blood clot in the lung.

Indeed, 5% of DVT sufferers who have contacted the website are pilots. In contrast to flight attendants who exercise enough during a flight to reduce the risk of DVT, pilots tend to move around less and the risk is higher, especially if coagulability is already high from a previous flight and they fall asleep sitting upright.

Airhealth's stance is supported by a number of studies such as Gianni Belcaro's LONFLIT series. However, in a presentation to the Royal Society of Medicine in London in January 2002, Dr. Michael Bagshaw, pointed to Swiss research published in 2001 which found professional pilots were less likely to suffer DVT than the general population, and that 16 out of 27 pilots who did had well recognized, pre-disposing factors.

There are, of course, many acute, short-term conditions or illnesses brought on by working as flight crew. The diet and eating patterns can suffer due to time zone changes and can lead to number of medical issues within individuals. In exotic locations, crew may be more susceptible to food poisoning or may be exposed to contagious illnesses as in the case of the recent Severe Acute Respiratory Syndrome (SARS) outbreak. Another very serious health risk is hypoxia which is an issue in its own right and can affect crew on both short and long haul flights.

Also referred to as "mountain sickness", hypoxia is a condition that can be caused by flying at altitude and can cause a pilot's mental coordination to slow down and may potentially reduce night vision. According to Group Captain David Gradwell, Consultant adviser in Aviation Medicine with the Royal Airforce, it is a condition that can affect even the fittest and youngest of pilots and there is no known predictor of susceptibility. Although it is extremely rare for flight crew to be affected by hypoxia, it is a potentially serious condition and there are often no symptoms. Research into this condition is ongoing with much of it being carried out in conjunction with aircraft air quality studies. One of the most notable studies has been instigated by the European Union (EU) and is primarily looking at lowering cabin altitude.

So will the ULH flights of the future pose an increased medical risk to flight crew? Certainly the view of the speakers at the RAeS seminar is that jury is still out on this matter. It is clear that fatigue is the primary concern and that crew on these flights will be carefully monitored. It could even be that ULH flights will prove safer if crews are doubled up and have adequate rest facilities onboard. It will be interesting to see what further research and monitoring on this matter will reveal.