Flying and Health — Page 116, Lesson 182

I want to walk you through the topic of flying and health, specifically the effects of radiation on aircrew and the critical importance of fitness to fly. Let's start with galactic radiation. This is a type of radiation that comes from outer space. The excerpt tells us that stratospheric absorption gives considerable protection in equatorial regions, but this effect declines to zero as the polar regions are approached. So the effects of galactic radiation are worst at the poles. Additionally, the effects of galactic radiation also increase with altitude. To give you a sense of scale, the Concorde — which flew at much higher altitudes than subsonic aircraft — was exposed to a galactic radiation dose of about twice that to which subsonic aircraft are exposed. Now, there is an international body called the International Committee on Radiation Protection. They recommend that the maximum annual permissible dose for the general public is 5 millisieverts, which is equivalent to 0.5 rem. A millisievert is a unit of radiation dose, and a rem is an older unit — 1 sievert equals 100 rem, so 5 millisieverts equals 0.5 rem. If Concorde were still in service, this annual limit of 5 millisieverts would equate to about 60 return trips across the Atlantic per year. Next, let's look at solar radiation. Solar radiation is of a lower energy than galactic radiation and emanates from the sun via solar flares. So while it's lower energy than galactic radiation, it can be intense and unpredictable. The excerpt tells us that adequate shielding on aircraft would impose uneconomic weight penalties. So instead of shielding the whole aircraft, Concorde had detectors to record exposure, which were mounted on the forward passenger cabin. Now, what can be done to reduce the effects of radiation? Designers and manufacturers are paying much more attention to the effects of radiation as the tendency for flights to operate at higher altitudes increases. For passengers, little can be done to avoid the effects other than keeping high altitude travel to a minimum. For crew, responsible operators will monitor crew exposure and will enforce appropriate rostering — meaning they schedule crew so that no individual exceeds safe exposure limits. What are the effects of excess radiation exposure? It will affect the central nervous system and damage organs. It can also cause cancer — especially of the skin. Now, let's move to a different but equally important topic: common ailments and fitness to fly. Minor ailments, such as a slight cold or mild food poisoning, can cause a deterioration of flying performance. The decision whether or not to fly requires careful consideration by a pilot. The rule is clear: if there is any doubt whatsoever with regard to personal fitness, a pilot should not fly. Finally, let's discuss drugs and self-medication. Apart from the primary purpose for which drugs are intended, it is generally true that most of them have some unwanted side effects. Individuals also vary in the way that the primary drug affects them. In some cases, due to a personal idiosyncrasy — meaning a unique personal reaction — a drug may have an adverse effect and the taker may rapidly become very ill. For these reasons, it is absolutely essential that aircrew only take medication which has been specifically prescribed by a medical aviation specialist who is aware of their profession. Self-medication is particularly dangerous. It not only carries the risk of suffering side effects but also the hazards associated with the underlying illness. The possible dangers of side effects may not be obvious, particularly when a mixture of drugs is contained in an apparently innocuous compound on sale to the general public in the local chemist.