Abstract
Flight Physiology is concerned with the physiological problems that pilots and passengers face when exposed to the conditions and pressures of air travel. The psychology of human beings is progressively modified to be effective to around 12,000 heights above sea altitude. This can be said to be the maximum value of the physiological effectiveness sector. Beyond this sector, physiological balance mechanisms most probably will be incapable of enduring the pressures of height above sea level. Pilots and especially military pilots undertake a sequence of training in high altitude building up low-pressure (hypobaric) compartments to reproduce initial phases of hypoxia. Hypoxia is a condition that occurs in the event of oxygen exhaustion in the body. This research paper looks at the role of flight physiology in flight operations. It also gives a detailed report of the harm that can be caused by a lack of sufficient oxygen at a certain height. The purpose of the research is to enlighten people on the role of flight physiology in safe flights.
Introduction
Flight Physiology is concerned with the physiological problems that pilots and passengers face when exposed to the conditions and pressures of air travel. The psychology of human beings is progressively modified to be effective at around 12,000 heights above sea altitude. (Aviation physiology, n.d.) This can be said to be the maximum value of the physiological effectiveness sector. Beyond this sector, physiological balance mechanisms most probably will be incapable of enduring the pressures of height above sea level. Pilots and especially military pilots undertake a sequence of training in high altitude building up low-pressure (hypobaric) compartments to reproduce initial phases of hypoxia. Hypoxia is a condition that occurs in the event of oxygen exhaustion in the body. (Kenneth, & Alistair, 2006)
The deficiency of oxygen is very dangerous to the pilot at high altitudes. This is what leads to the condition called hypoxia, which translated means deprivation of oxygen. In the situation where a pilot breathes in the air at high altitudes, there is usually insufficient oxygen pressure to allow ample quantities of oxygen into the casing of the lungs. This, therefore, means the oxygen is not reaching the bloodstream for it to be transported to the tissues of a person. This then leads to the malfunction of vital organs such as the brain. The pilot is not able to realize his condition and this leads to more serious consequences. In the early stages, one feels as though they have a soft intoxication of alcohol. Oxygen deficiency occurs in the brain first thus leading to a loss of sensation and the body becomes disoriented. Since the mind is not functioning well, the hands and limps turn out to be clumsy while the pilot is completely unaware. The pilot also becomes drowsy, unenergetic, and detached with no sense of safety measures. (The Unseen Menace, n.d.)
The pilot may become dizzy with a sense of stinging on the skin while the hypoxia is getting bad. The pilot will also experience a small headache without being fully aware and as the altitude gets higher, the situation worsens. The heartbeat becomes faster while the skin begins to change to blue and cannot be able to see far. With hypoxia, the pilot may feel as though he is flying very well and comfortably. Once at around 20,000 feet, the pilot’s vision becomes dull in such a way he cannot see at all. The pilot may not hear the sound of the engine and starts having problems breathing with the heart racing fast. In this situation, the pilot has no idea of what is happening and once at 25,000 feet, the pilot will most likely collapse. The pilot is also likely to die unless oxygen is supplied as soon as possible. (Hobler, &Carey, 1973, p.200)
Hypoxic hypoxia is caused by the malfunctioning system of oxygenation into the lungs. This means the insufficient supply of oxygen into the body entirely. This is due to the low pressure of oxygen like the one in high altitude. (Frushour, 2000) It is because of oxygen inhaled in the mixture of the adapted atmosphere of open drainage or in from nitrous oxide. Low pressure of oxygen into the lungs is the situation where there is a change from the breathed in anesthesia to atmospheric pressure, which is because of the Fink effect. It also comes about because of oxygen diffusion of the blood in the case of sleep apnea. Irregular pulmonary operation is another cause of hypoxic hypoxia. The other cause is due to airway hindrance or side-by-side shunts in the heart. Shunts occur because of failed alveoli due to hindrance of aeration in the region around the lung. (The Unseen Menace, n.d.)
Below is a graph showing the effects of oxygen deficiency.
Potential Effects of Oxygen-Deficient Atmospheres
Ischemic hypoxia or stagnant hypoxia occurs in the case where there is local limitation in the movement of blood that is sufficiently oxygenated. This causes the part of the body that receives this blood to be short of oxygen. Instances of this occur in cerebral ischemia, ischemic heart disease as well as intrauterine hypoxia. Anemic hypoxia is caused by a decline in the number of useful hemoglobin, which means that the red blood cells are less. Oxygen affinity hypoxia is caused by the inability of hemoglobin to produce oxygen. Hypemic hypoxia is the case where principal oxygen pressure is regular but the entire oxygen component of the blood is very low. (Walton, 2007)
Histotoxic hypoxia is caused by the failure of the cells to efficiently utilize oxygen. In this case, one may breathe in the oxygen and enter the cells in sufficient quantities. However, the cell is not able to use the oxygen. Therefore, because of interruption of oxygen giving phosphorylation enzymes process, tissue chambers are incapable of utilizing oxygen sufficiently. This destruction of cellular respiration is mainly due to alcohol as well as drugs. It can also be due to contact with poisonous gases in badly aerated regions or environment. The poisonous gases hinder the potential of the hemoglobin to carry and discharge oxygen. (Walton, 2007)
Cerebral hypoxia comes about when the brain gets insufficient oxygen that is needed to carry out its metabolic activities. In the human body, the brain chambers are very sensitive to oxygen deficiency. It only takes five minutes of oxygen deprivation for the brain to begin dying. If cerebral hypoxia lasts for more than five minutes, the individual will be exposed to convulsions, coma and in other cases brain damage. It is important to know the symptoms of cerebral hypoxia since it is a serious disease and every second is vital to helping such a person. (Nucleus medical media, n.d) Chronic Hypoxia can be caused by various medical circumstances including every disease related to persistent blood failure, cardiac mayhem, and persistent pulmonary ailments. It also happens to pilots who are getting used to high altitudes following a shift from the sea level. Situations that advance chronic hypoxia slowly bring about deterioration in how the tissues are oxygenated. This causes physiological trauma that leads to multiple body mechanisms. In persons who have persistent lung ailments, chronic hypoxia stimulates low arterial vein density because of the damage brought about by the advancement of the condition. (Gross, 2006)
There are a number of thing that pilots can do to ensure safety while flying. The pilot should always ensure that they have oxygen in the aircraft and in case it is not, they should not fly above 12,500 feet above sea level. He should also make use of the oxygen in any height above 12,500 because hypoxia will not allow one to know when they are in danger. In cases where there is bad weather, the pilot should make the decision to go around it in case it is not possible to fly over it. The pilot should be able to use oxygen in the situation where the flight has been prolonged and is around 12’500 feet. When it comes to night flights, the pilot should always use oxygen without exception. This also helps in improving the vision and ensuring a safe flight all the way. Pilots should learn to inhale normally while utilizing the oxygen since quick and forceful inhaling can bring about failure of consciousness. (Adrian, 2010)
Pilots should be able to know that no person is excluded from hypoxia thus oxygen supply is mandatory. Even though some pilot can fly at a higher feet than others without oxygen supply it is always good to be safe than sorry. Those pilots who are of age, those who are bigger, those who are not in form as well as smokers should ensure they keep to a maximum of up to 8,000 to 10,000 feet, except if they are using oxygen. Nowadays, executive airplanes have pressurized cabins and they frequently fly all the way to 40,000 feet. These planes have outfitted pressure inhaling oxygen apparatus, which provide oxygen in case of a minor pressure. In situations where there is no cabin pressure at heights over 38,000 feet, the oxygen in the lungs may not be sustained if the oxygen is not raised. In this way, hypoxia will take place very fast and pure oxygen need to be added to reinstate the body to a non-hypoxic level.
Pressure inhaling involves the change of the regular respiratory mode in such a way that lungs have to be working in the time of breathing in rather than breathing out. It is important to note that, even if pressure breathing improves a pilot’s lenience to higher heights, it should be addressed in regular flights. The pressure breathing is an emergency apparatus and should be used in situations where cabin pressurization is not working. In this way, oxygen will be there in times of decline to lower heights and it will not be needed. Research has revealed that pilots who are soaring in unpressurized aircrafts at heights around 8,000 and 12,000 with no extra oxygen are prone to more errors than oxygenated pilots are. Hyperbaric oxygen should be used because it enhances the oxygen circulation in the body in this way ensuring the body tissues are oxygenated.
An example of an accident that was caused by the effects of hypoxia was the crash of Helios Airways Flight 522. A Helios Airways Boeing 737-300 on 14th August crashed in the north of Marathon and Varnavas Greece. There were 121 passengers on board and they all died in the crash. Apparently, the crew had not set the pressurization apparatus to auto, which was wrong going by the principles of Boeing. Moments after the plane left the ground, the cabin altitude signals went on because of pressurization. The crew then mistook it for a take-off arrangement signal, which shows the plane was not prepared to fly and they proceeded to shut it down. At 14,000 feet, the oxygen visors in the cabin automatically set up. It was during this time that the crew got in touch with the ground engineers. A few minutes later larger warning beams came on showing something wrong was in the system. (Phillips, 2005)
The crew mistook that for the system being overheated. The captain told the engineer who was on land that the aeration fanlights were turned off. This showed that the captain was experiencing hypoxia since that aircraft did not have such lights. The engineer inferred to the captain to repeat his information. The captain then said that the equipment cooling lights were off, which was another sign of confusion. The engineer told him everything was all right and the captain asked him another confused question. The plane did not manage to contact air traffic controllers and within moments, the plane ran out of fuel and crashed. The cause of the plane crash after investigations showed that the cabin pressurization power regulator was put to manual. It was not reset to auto once the post-maintenance pressurization controls were finished. (Phillips, 2005)
Flight and Crash (Time Table)
Below is a graph showing the timetable for the crash of an aircraft caused by the effects of hypoxia:
Conclusion
Flight physiology is very important in aviation sector for all crewmembers. The aircrew should be well trained on the topic to ensure that mistakes do not happen that could lead to a disaster. Flight safety can be improved by having the concerned persons adhere to the flight physiology requirements. In the cases where there is a situation involving hypoxia and other related flight physiology issues, the crew should be able to react within proper procedures.
Hypoxia can be very dangerous and therefore the pilot should be well informed about the condition. He should ensure that the right procedure is followed to ensure that the aircraft reaches its destination safely. He should be able to coordinate his crew in the event of such a condition to ensure that an emergency is declared and that the co-pilot can take over. Their work should be well coordinated and the right training in flight physiology should be ensured. The passengers should also be made aware of this situation and given the right instructions in cases of an emergency.
Recommendations
Having known the effects of flight physiology, I recommend that pilots should be trained well before being given the license to fly. They should be able to know when it is necessary to put the oxygen in order to ensure safety of the passengers. Symptoms of hypoxia are not very vivid and the pilot will not be able to know their condition therefore it is paramount that they receive proper training on this. The pilot should ensure proper control and checking of the altitude to ensure he does not fly in dangerous conditions.
The aircrew should also be well trained to ensure they know the measures to take in case there is a condition of hypoxia with the pilot or any other passenger. They should give the person the required attention and first aid to ensure calmness and coordination. Hypoxia is very unpredictable and its effects can be devastating therefore, proper medical attention should be provided.
References
Adrian, K. (2010). Top 5 Scariest Things about Flying and How to Stay Safe. Web.
Aviation physiology. (n.d.). 2010. Web.
Frushour, S. (2000). Hypoxia and flying. Web.
Gross, K. (2006). Cerebral hypoxia. Web.
Hobler, K.E.; Carey, L, C. (1973). “Effect of acute progressive hypoxemia on cardiac output and plasma excess lactate”. Ann Surg. 177 (2): 199–202.
Kenneth, B, & Alistair, S. (2006). “Altitude oxygen calculator”. Apex (Altitude Physiology Expeditions). Web.
Nucleus medical media. (n.d). Cerebral hypoxia. 2010. Web.
Phillips, D. (2005). “Crash inquiry focuses on oxygen mask use”. International Herald Tribune. Web.
The Unseen Menace. (n.d.). The Effects of Oxygen deficiency. 2010. Web.
Walton, C. (2007). Hypoxia causes, Symptoms and Treatment options. Web.