For several people, travelling on an aircraft is a nightmare. Adjusting to a restricted space with little leg-room and feeling your ear pop during take-off or landing is enough to dissuade many people from flying. Long distance journeys make the trip all the more cumbersome as being confined to a small space causes the muscle to spasm. However some people have taken air-travel to a whole new level by travelling as stowaways.
The wheels of the aircraft open out only during take-off and landing. During the flight the wheel retracts or folds into a space known as the wheel well. The space left behind in the wheel well once the wheel retracts is approximately 6-8 sq.ft, which is less than the size of a car boot. A man travelled all the way from Johannesburg, South Africa to London by hiding in the wheel well of an aircraft. He managed to survive the 11-hour ordeal despite the drop in temperature and insufficiency in oxygen.
This man is not an exception. In the last century approximately 105 people have tried to travel in the underbelly of the aircraft and a fourth of them have managed to survive the ordeal. Some are crushed when the wheel retracts into the compartment and a minority of them fall to death when the wheel opens during landing. The prime physiological factors that contribute the death of the person are hypoxia (lack of oxygen) and hypothermia (low body temperature).
Under normal circumstances, the lungs assist in the inhalation of oxygen and the brain controls the distribution of oxygen to the other organs to bring about proper functioning of organs. In higher altitudes, the amount of oxygen present in the air is insufficient to sustain the normal functions of the body. The carotid body, a portion of the carotid artery senses the lack of oxygen and alerts the brain. The brain responds by going into a hibernate mode, which makes the person unconscious. Once the person is unconscious, his body ceases to perform any voluntary functions like motion of limbs, speech etc. The person goes into a comatose state as the brain shuts off the supply of blood to the limbs and other extremities. Oxygen is transported through blood and regulating the supply of blood to voluntary organs aids in optimizing the minimal amount of oxygen available.
Mountaineers generally spend a few days at lower mid altitudes to allow their body to acclimatize. At the top of the Mount Everest Summit, the amount of oxygen present in the air is only one third of what is available at sea level. By acclimatizing, the body gets used to the insufficiency of oxygen gradually as the process occurs at several altitudes. In the case of plane stowaways, this is not the case as the body has no time to get used to the surroundings as the aircraft climbs to an altitude either equal to or greater than the height of the Everest in less than few minutes. Hence the body is faces an unfamiliar situation and the brain in an attempt to regain control goes into survival mode.
An optimum temperature is necessary for the functioning of the human body. In exceptionally high altitudes, the temperature is sometimes less than -60°C. This induces hypothermia or exceptionally low body temperature in the body. Hypothermia is usually fatal, but in the case of hypoxia, hypothermia is beneficial as the low temperatures results in slowing down the flow of blood to the extremities. This aids in the circulation of warm blood to the essential organs such as the brain and heart. In some cases, the heat generated by the electronic circuitry of the aircraft helps in increasing the temperature and aids in avoiding frostbite.
Humans are generally homeothermic or warm-blooded as the body regulates its own core temperature in order to maintain it at a constant. In animals like the crocodile, the external environment impacts the body temperature of the body. In exceptionally low temperatures, the human body becomes poikilothermic or cold blooded. The body temperature is influenced by the external temperature in contrast with normal conditions where external conditions do not influence the body temperature. Seasoned mountaineers and mountain dwellers do not exhibit poikilothermism as acclimatization prevents it. Poikilothermism is harmful, but is beneficial for stowaways as it regulates oxygen flow by making controlling blood flow.
Though the human body adjusts itself to its surroundings, travelling amidst insufficient oxygen and low temperature can be fatal. 77% of people who travel as stowaways do not complete the journey alive. Mid-air deaths are usually caused by extreme hypoxia when the amount of oxygen present in the air is insufficient to sustain even basic body functions like circulation and respiration. Hypothermia may also contribute to deaths when the person’s body gets frozen solid and the blood ceases to flow. The amount of oxygen present in the air and the temperature are inversely proportional to the altitude of the aircraft. Hence, stowaways on low-altitude flights are more likely to remain alive the end of the journey.