Managing Human Limitations And Improving Performances In a Safety Environment

„Elie Carafoli” Aerospace Sciences Department

Managing human limitations and improving performances in a safety environment

BEng Final Project

Author: Preda Emilian-Costas

Supervisor: Ș.L. Dr. Ing. Silviu Zancu

Session: July 2016

Anti-Plagiarism Declaration

I, the undersigned Emilian-Costas Preda, student of the University Politehnica of Bucharest, Faculty of Aerospace Engineering declare herewith and certify that this final project is the result of my own, original, individual work. All the external sources of information used were quoted and included in the References. All the figures, diagrams, and tables taken from external sources include a reference to the source.

Date: _________ Signature: __________________________

Table of Figures

Figure 1.1 – Vitruvian Man (Source: Leonardo Da Vinci – The Complete Works)………………………12

Figure 1.2 – Flying Machine (Source: Leonardo Da Vinci – The Complete Works)…………………….13

Figure 2.1 – Man Ready for Survival (Source: Life’s Little Mysteries)………………………………….15

Figure 2.2 – Rat sleep deprivation experiment (Source: livescience.com)……………………………….16

Figure 2.3 – Airline Seating (Source: popsci.com/science)………………………………………………18

Figure 2.4 – Safe Zone graphs (Source: NASA)………………………………………………………….20

Figure 3.1 – Cross section of the eye (Source: Human Body Pushing the Limits Documentary)…….…..21

Figure 3.2 – Thighbone on a hydraulic press (Source: Human Body Pushing the Limits Documentary)..23

Figure 3.3 – Weave of collagen fibres (Source: Human Body Pushing the Limits Documentary)…….…24

Figure 3.4 – Collagen fibres (Source: Human Body Pushing the Limits Documentary)…………………25

Figure 3.5 – Sweat glands drying out (Source: Human Body Pushing the Limits Documentary)………..27

Figure 3.6 – Endorphins smothering the synapse (Source: Human Body Pushing the Limits Doc)………29

Figure 3.7 – Brain’s thought centre (Source: Human Body Pushing the Limits Documentary)………….30

Figure 3.8 – Brain’s emergency control (Source: Human Body Pushing the Limits Documentary)……..30

Figure 3.9 – Kissing vs. Eating Chocolate (Source: Human Body Pushing the Limits Documentary)…..31

Figure 3.10 – Hypothalamus (Source: Human Body Pushing the Limits Documentary)………………….31

Figure 3.11 – Pineal Gland (Source: Human Body Pushing the Limits Documentary)……………….….33

Figure 4.1 – Level of Pilot Capabilities during Flight (Source: Adapted from Transport Canada’s Human Factors for Aviation: Basic Handbook)…………………………………………………………….……..35

Figure 4.2 – The Stress Response Curve (Source: Adapted from Nixon P, Practitioner, 1979)……….…39

Figure 4.3 – The Inverted-U Relationship between Pressure and Performance (Source: mindtools.com).40

Figure 4.4 – Add/Run Window……………………………………………………………………………42

Figure 4.5 – Input Window………………………………………………………………………………..42

Figure 4.6 – Controllers’ Shifts Table Window……………………………………………………………43

Figure 4.7 – ATFCM………………………………………………………………………………………43

Figure 4.8 – Becky’s Timetable……………………………………………………………………………45

Figure 4.9 – Freddy’s Timetable…………………………………………………………………………..45

Figure 4.10 – Fred and John’s Timetables…………………………………………………………………46

Figure 5.1 – Professor Wilbur and his first G-Suit (Source: magazine.utoronto.ca)………………………50

Table of Acronyms

Executive Summary (English)

Safety has always been the number one priority in aviation. Almost every year improvements are brought to the field, even though testing, approving and implementing those takes a lot of time. Nevertheless, a countless number of measures have been added in order to avoid any accidents from happening, both in the air and on ground. Because this thesis is mainly about taking the human body beyond its limits, we will be talking about the principles and equipment used to take the ordinary human boundaries to a new level.

The human body is not without its weaknesses. To better increase efficiency, we must understand what our limits are and either work around them or find a means to bypass these limits (either by training or by creating devices that help us perform in otherwise unbearable conditions). Even the creation of aircraft itself is a means to overcome our lack of flying capabilities.

Nowadays, the human being in their daily routine rarely put to extreme conditions where our primal instincts are put to use, but that does not mean they are not there, inside of us; the human body stores immense amounts of power ready to be unleashed when needed most. Every man has its limits, but our bodies may surprise us when we can lift objects that are much heavier than our own body, run faster than we would imagine possible or survive without nutrition for days, even weeks when we are pushed to the limit. When in peril, our brain takes charge of our body without even knowing, enhancing our senses, increasing our strength and even replacing our ration with instant, on instinct decisions in situations that would otherwise be fatal. It is because of these traits that man can never be fully replaced by machines, especially when the lives of others is at stake.

One of the key factors that must be taken into account in all jobs that involve rapid decision making is stress. Stress and fatigue are the most important factors that are closely tied to performance and must never be taken lightly. Because of these, people that would otherwise be more than capable of performing their duties at optimum level end up falling behind their work and can often lead to serious repercussions. The first step to better managing a team is to understand each and everyone’s limits and then rearranging them with regard to their capacities such that the right person is always on the job when the task is accordingly demanding. This in the foundation of the program shown in the thesis, which will be replacing the conventional timetable for controllers with a new, more dynamic one that not only takes the level of performance of each individual into consideration, but also the stress tolerance of each one.

The most significant addition to an aircraft, before the closed cockpit was invented, was the pilot Flight Suit. First made out of leather to prevent injury from debris in WWI, it changed to electrically heated suits in WWII to allow higher altitude flights and then G-Suits made for pilots to survive flights with extreme G-forces.

All in all this project is focused on getting the reader familiar with the safety department in aviation, to have an understanding about the human limits and capabilities, to better organize people depending on their capabilities and some general information about the physical stresses our bodies are subjected to during high G-force flights and the G-Suit that helps overcome these negative effects.

Executive Summary (Română)

Siguranța a fost întotdeauna prioritatea numărul unu in aviație. Aproape în fiecare an îmbunătățiri sunt aduse în domeniu chiar dacă testarea, aprobarea și implementarea lor durează mult timp. În orice caz, nenumărate măsuri de siguranță au fost adăugate spre a evita orice accident, atât în zbor cât si pe sol. Deoarece lucrarea acoperă in principal depășirea limitelor umane, vom vorbi despre principiile si echipamentele folosite pentru a aduce limita umana spre un nou nivel.

Corpul uman nu este lipsit de slăbiciuni. Pentru a mări eficiența trebuie să înțelegem care sunt limitele noastre și ori să ne adaptăm in funcție de ele, ori să găsim modalități de a depăși aceste limite (fie prin antrenament, fie prin crearea unor echipamente care ne ajută să lucrăm în condiții fără de care ar fi imposibil de lucrat). Până și inventarea avionului este o metodă de a trece peste limitarea noastră de a ne deplasa numai pe sol.

În zilele noastre corpul uman în rutina sa zilnică este rar pus in condiții extreme unde instinctele noastre primare sunt puse în funcțiune, dar asta nu înseamnă că nu le mai avem; corpul uman dispune de cantități semnificative de putere gata de a fi degajate când este mai mare nevoie de ea. Orice om are limitele sale, dar corpurile noastre s-ar putea să ne surprindă când ajungem să ridicăm obiecte mult mai grele decât noi, să alergăm mai repede decât ne-am putut imagina că este posibil sau să supraviețuim fără hrană sau apă zile, chiar săptămâni întregi când suntem împinși la limită. Când suntem în pericol, creierul nostru preia conducerea fără ca noi să ne dăm seama, îmbunătățindu-ne simțurile, crescând puterea brută și chiar înlocuind gândirea rațională cu decizii instante, bazate pe instinct în situații fără de care ne-ar fi fatale. Datorită acestor trăsături omul nu va putea fi niciodată pe deplin înlocuit de mașinării, mai ales când viața altora este la mijloc.

Unul din factorii cheie care trebuie luat în considerare în toate domeniile care implică luarea de decizii rapide este stresul. Stresul și oboseala sunt cei mai importanți factori care sunt strâns legați de performanță și nu trebuie neglijați niciodată. Din cauza lor, persoane fără de care ar fi mai mult decât capabili să își îndeplinească îndatoririle la nivel optim ajung să facă greșeli care ar putea duce la repercusiuni serioase. Primul pas spre o mai bună organizare a unei echipe este sa înțelegi limitele fiecăruia și apoi să îi reorganizezi in funcție de capacitățile lor în așa fel încât persoana potrivită este întotdeauna la datorie când munca este de așa natură. Aceasta este fundația programului prezentat în lucrare, care va înlocui orarul convențional pentru controlori cu un nou, mai dinamic program care nu numai ca ia in considerare nivelul de performanță al individualului, dar si nivelul său de toleranță la stres.

Cea mai semnificativă adiție a unei aeronave, înainte de a fi inventată carlinga închisă, a fost costumul de zbor. Făcut inițial din piele pentru a preveni accidentările datorate resturilor în zbor în timpul primului război mondial, acesta s-a schimbat în costume încălzite electric in timpul celui de-al doilea război mondial pentru a facilita zborurile la altitudini mai mari, urmate apoi de G-Suits făcute pentru piloți pentru a supraviețui zborurilor cu forțe G extreme.

Acest proiect în ansamblu este concentrat spre a familiariza cititorul cu domeniul de siguranță în aviație, pentru a avea o mai bună înțelegere despre capacitățile si limitele umane, pentru a mai bine organiza oamenii în funcție de capacitățile lor, precum și câteva informații generale despre impactul fizic pe care îl suferă corpurile noastre când sunt supuși unor forțe G mari și despre G-Suit care ajută să diminueze aceste efecte negative.

What has already been done

A very important aspect in all areas of aviation is the physical and psychical condition of the pilot and air traffic controller, who play the most important roles in flight management. Both have to endure rigorous exams before given such a position to ensure that every individual is up to the task. Training rooms are created, as well as quizzes and tests. Constant revaluations are also demanded to make sure the individual is still up to the task. Still, recent history has shown that even the most drastic evaluations can't fully surface everyone. A new system needs to be installed that not only tests one's capabilities, but also how the job impacts the individual by constantly evaluating their stress tolerance levels and rearranging shifts and schedules such that every team meets optimum performance and when the job becomes most demanding, the right person is put on the proper position. The program presented in this thesis will evaluate the stress tolerance levels of all controllers and replace the traditional twelve hours shift of the controllers with a more dynamic timetable that better fits each and everyone’s unique capacities.

Introduction

The goal of this scientific paper is to create a better understanding of the human capabilities and to introduce a new concept of air traffic controller management which better suits each individual’s capacity in terms of stress tolerance. Whist everyone is always focused on creating more and more performant systems and aircraft that perform better, the management of these systems at the same time become more and more complicated. Although the human factors field is not taken lightly and all new systems are taken through a long rigorous trial before release, there is still a slight tendency for the machine complications to overpass the capacity of the individual managing these systems. Since then, standards were implemented for such machines so that adaptation is made easy and this concept still remains until today.

The history of Human Factors and Ergonomics dated as early as the late 1600s when Leonardo Da Vinci started studying the human body to see if it is capable of flying. The most decisive moment was during the Second World War when both ground and air vehicles started to fail due to improper maintenance and control. This was due to the fact that there was no standard layout for cockpits and other sections of the machines made it impossible to learn every possible layout both for the pilot and the engineer.

Most people do not realise what their bodies are fully capable of. We may think we know how fast we can run or how much weight we can lift, but in reality we can do much more. Our bodies store extra power for emergency situations and the more we understand about these hidden sources, the more possible it is to tap into them voluntarily. Training and equipment might also be used to even further remove the constraints imposed by our body’s physiognomy.

Aside from understanding our boundaries, people are ultimately different from one another and as consequence, their capabilities may differ in certain fields. We must accept this difference and instead of forcing people to perform better where there is no room for improvement, accept them as they are and manage teams according to each’s performances. A dynamic workspace must replace the conventional, often fixed timetables where work is more demanding at certain times such that proper personnel must be present at those times to deal with the increased workload. For a more faster and stable rescheduling, the process will be done automatically through a computer program.

Although implementing this system will be a difficult task and as any other project in time it will prove to be not without its faults, this concept will still prove to be an improvement to any workspace as it takes several factors into account when creating a timetable.

Human Factors

Human factors (or ergonomics) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. Human factors contribute to the design and evaluation of tasks, jobs, products, environments and systems in order to make them compatible with the needs, abilities and limitations of people.

"Human Factors is a body of knowledge about human abilities, human limitations, and other human characteristics that are relevant to design. Human factors engineering is the application of human factors information to the design of tools, machines, systems, tasks, jobs, and environments for safe, comfortable, and effective human use."

"Ergonomics is the design and engineering of human-machine systems for the purpose of enhancing human performance."

"The study of human factors examines how humans interact with machines and other people (pilots, air traffic controllers, or design and acquisition personnel) and determines whether procedures and regulations take into account human abilities and limitations."

There are many definitions to this concept, all referring to the optimization of the relationship between people and their practices, creating a safe and comfortable workplace to increase the overall safety and efficiency.

History

Where did the attention to human factors really start? Going back to Leonardo da Vinci, the first to ever study human factors (late 1600), he drew the Vitruvian Man with all the anthropometric measures of strength and size. He was trying to decide if the human was strong enough to propel an aircraft.

In the early 1900 industrial engineers such as Frank and Lillian Gilbreth were trying to reduce human error in medicine. They were using call-backs when communicating in the operating room (much like we are using nowadays in aviation communication). At the same time, Orville and Wilbur Wright (the Wright brothers) were figuring out how to fit a human into the first aircraft. Shortly after that, the U.Ss Army was determining the required physical and mental characteristics for flight training candidates. They were also considering human factors as contributing causes to accidents.

operational accidents were caused by human error. Those errors were often a result of poor aircraft cockpit layout and non-standardised displays and controls. On the maintenance side it became obvious that maintenance was neglected because the aircraft design did not give proper attention to maintainability. That led to efforts to design and build aircraft not only for flying, but also for fixing. The Ergonomics Research Society emerged in 1949-1950 from various meetings held in London, Oxford and Cambridge. The intention was to facilitate the exchange of ideas and expertise between the many disciplines which had made a contribution to the increased effectiveness of human performance during the time of war and to extend the application of these principles beyond the military sphere. The first important symposium was held in Birmingham in 1951 called "Human Factors in Equipment Design" and the second at Cranfield in 1952 on "Fatigue". The Medical Research Council (MRC) sponsored the Climate and Working Efficiency Research Unit in Oxford and the Applied Psychology Research Unit in Cambridge. The MRC was responsible during the war (and still remains today) for the Personnel Research Committees of the Royal Navy, the Royal Air Force and the Army. It was activities under the aegis of these committees which could be regarded as the origin of ergonomics.

In 1957 in the U.S. the human factors and ergonomics society was established. There are 5 thousand members today. Two years later The International Ergonomics Association was formed.

aircraft and also on maintenance human factors.

By 1989 the FAA as well as Transport Canada appointed personnel to dedicate themselves to maintenance human factors. Since then, this type of activity has continued throughout the world.

Human Factors in Aviation Maintenance

In the aviation industry human factors plays a key role in its development. Here are twelve primary contributing factors that affect human performance and cause error in the aviation maintenance.

Most revenue service flight happen during the daytime, which means that aviation maintenance usually occur during the night when people's performance is typically at a low point. The problem with fatigue is that as aviation professionals we tend to overestimate our ability to deal with it and underestimate the problem.

When we are lacking the correct resources such as tools, parts, financial resource or knowledge, the temptation is to take a shortcut to get the job done at all costs. This is usually done by bypassing regulations or procedures in accordance with the way that the maintenance manual states.

We lead busy lives and often there are many things that happen each day that sometimes take our attention away from the task at hand. Distractions, one of the killers, as distractions are the leading cause for forgetting a task. The key to dealing with distractions is to recognise that you have been distracted and double check your work.

We deal with a lot of pressure each and every single day. Things such as deadlines, key performance indicators or financial targets sometimes put an immense amount of pressure that can lead us into a position where we are not aware of what is going on around us. Ensuring that quality and safety are always first is critical.

Sometimes we are put into situations where we're unsure or afraid to speak our minds in a way that communicates our feelings, opinions, concerns, beliefs and needs in a positive and productive manner. We need to make sure that at all times we do not compromise our own standards (also known as lack of assertiveness).

A lot of the work that is done in the aviation are team affairs. No single person can be responsible for the safe outcome of all tasks. However, if somebody is not contributing to the team effort, this can lead to unsafe conditions. This means that workers must rely on colleagues to make sure that work is done safely and effectively.

Often we have procedures that are agreed upon by the majority of the group, but are not documented, referred to as norms. The danger at norms occurs when they detract from the established safety or quality standard. This can present a risk to aviation standards' quality and airworthiness.

The human body is fascinating. It will naturally respond to events of the recent past or anticipate the events of the near future subconsciously. Danger comes when it seems to be no escape from the events, such as family illness, financial difficulty or relational issues which seem that there's no escape from. These factors cause stress and can easily reduce the quality of the job while under it.

Sometimes we fall into a situation where we have a sense of self-satisfaction, but accompanied by a lack of awareness to the danger. This is referred to as complacency. Complacency can result from overconfidence, stress, pressure, boredom or many other factors as well.

If we don’t have the resources that we need to perform our task correctly such as tools, manuals, parts, then the temptation is to do what we can to complete the job, regardless whether or not we have the right material. Not having proper knowledge decreases the quality in airworthiness risk if we try to accomplish a task when we lack the resources.

Poor communication is one of the most common, but also critical human factors' elements and it is estimated that only about 30% of message content is received and understood correctly. This needs to be taken into account whenever we try to communicate with other co-workers, customers or colleagues.

Sometimes when we're not vigilant we lose focus on the effect our actions may have on others. If we create a quality or safety risk it is our responsibility to make sure that we educate other people in the future that may come across that risk that it exists. This can be done with signs, Passover logs or other information. Not doing that will create a lack of awareness.

These 12 primary contributing factors to human error are known in the aviation world as The Dirty Dozen. The Dirty Dozen were developed by Gordon Dupont in 1993 as a method to improve human awareness about their interactions in aviation maintenance.

The Human Limitations

When we speak about limitations, we refer to an individual’s or even an object’s boundary while operating a certain task. There are two kinds of limitations:

Technical Limitations – where in order to overcome it, you need to upgrade or replace the device required for that specific task;

“Human Factor” Limitations – in which case the capability of performing certain tasks depend on the individual’s skills and traits and can only be improved through training and exercise.

When we speak about the human limitations, we refer to both the physical and psychological boundary of the human being. Although these limits can be heightened through means mentioned above, there are certain points which you cannot pass without any external aid. For example nobody can run faster than 50 km/h (43 km/h being the fastest recorded speed) and you can’t imagine a colour beyond that of the visible spectrum.

Figure 2.1 – Man Ready for Survival

Put a human anywhere in the known universe except for the thin shell of space that extends a couple of miles above or below sea level on Earth, and we perish within minutes. As strong and resilient as the human body seems in some situations, considered in the context of the cosmos as a whole, it's unnervingly fragile. Our bones may snap after falling only a few meters from the ground, our body can function in a relative narrow range of temperatures and we cannot survive on our own at altitudes over 8000 meters. Machines, meanwhile, can take a lot. The wings of a Boeing 777, for instance, can bend as much as 24 feet from their resting position, and any turbulence powerful enough to bend them that far will damage the passengers long before it damages the airplane.

Many of the boundaries within which a typical human can survive have been fully established; the well-known "rule of threes" dictates how long we can forgo air, water and food (roughly three minutes, three days and three weeks, respectively). Other limits are more speculative, because people have seldom, if ever, tested them. For example, how long can you stay awake before you die? How high in altitude can you climb before suffocating? How much acceleration can your body withstand before it rips apart? Experiments over the decades, either intentional, others accidental, have helped stake out the domain within which we, literally, live.

How long can we stay awake?

Air Force pilots have been known to become so delirious after three or four days of sleep deprivation that they crash their planes (having fallen asleep). Even staying awake a whole day impairs driving abilities as much as being under the influence of alcohol. The absolute longest anyone has voluntarily stayed awake before nodding off is 264 hours (about 11 days). Before falling asleep on day 11, he was unable to move.

How much radiation can we absorb?

Radiation poses a long-term danger because it mutates DNA, rewriting the genetic code in ways that can lead to cancerous growth of cells. But how much radiation will strike you dead right away? According to Peter Caracappa, a nuclear engineer and radiation safety specialist at Rensselaer Polytechnic Institute, 5 and 6 Sieverts (Sv) over the course of a few minutes will shred up too many cells for your body to fix at once. "The longer the time period over which the dose is accumulated, the higher that range would be, since the body works to repair itself over that time as well".

As a point of comparison, some workers at Japan's Fukushima nuclear plant absorbed 0.4 to 1 Sv of radiation per hour while contending with the nuclear disaster last March. Although they survived in the short term, their lifetime cancer risk increased, scientists have said.

Even if one steers clear of nuclear disasters and supernova explosions, the natural background radiation we all experience on Earth (from sources like uranium in the soil, cosmic rays and medical devices) increases our chance of developing cancer in a given year by 0.025 percent. This sets a bizarre upper limit on the human life span.

"An average person … receiving an average background radiation dose every year over 4,000 years, in the absence of all other influences, would be reasonably assured of contracting a radiation-induced cancer". In short, even if we eventually manage to eradicate all disease and switch off the genetic commands that tell our bodies to age, we will never live past age 4,000.

How much can we accelerate?

Humans are frail. The rib cage protects our heart from rough impacts, but it's rather weak against the kinds of jostling that technology has made possible today. Just how much acceleration can our organs tolerate?

NASA and military researchers have made strides in answering that question for the purposes of safe spacecraft and aircraft design. Lateral acceleration (sudden movements to the sides) puts heavy stresses on our insides because of the asymmetry of the forces. “Going forward too fast is dangerous enough, but a sudden sideways knock can be deadly. Most airplanes' overhead bins can withstand up to 14 G of lateral acceleration, but humans confronted by the same force must either envelop themselves in racecar-style seats or risk having their organs torn loose.” . Head-to-foot motion, meanwhile, plunges all the blood to the feet. Between 4 and 8 longitudinal G will make you unconscious.

Forward or backward acceleration appears to go easiest on the body, because they allow the head and heart to accelerate together. Military experiments in the 1940s and 1950s with a "human decelerator," essentially a rocket that travelled back and forth across Edwards Air Force base in California, suggest we can survive slowing down at a rate of 45 G, or the equivalent of the gravity of 45 Earths. At that rate, you slow from 630 miles per hour to 0 mph in fractions of a second over a few hundred feet.

Much of what we know is drawn anecdotally from the violent, often accidental experiences of airmen and astronauts. That's because engineers can't test humans the way they can other components of an aircraft. In designing one, "you can stress a part until it breaks. The human body is the only system in engineering that you can't take to failure." In 1966 a test pilot named Bill Weaver managed to eject when his SR-71 Blackbird broke apart at Mach 3.18. His systems officer was killed, but at 78,000 feet Weaver survived more than 2,000 mph of air resistance, revealing that a human can in fact withstand incredible shock at a very high altitude, at least when protected by a pressurized suit.

Military and NASA researchers don't really investigate human comfort, at least not in the way that a commercial traveler might hope. They aren't attempting to engineer conditions that will convince the traveler to fly a particular airline or buy a particular car. NASA engineer Dustin Gohmert, who designed seat systems for the crew module of the Orion spacecraft, explains the military-civilian distinction in straightforward terms. "Comfort itself is difficult to quantify. We look primarily at the safety of the crew."

Figure 2.3 – Airlines want to pack the maximum amount of people into the minimum amount of space, and it is safety, not comfort, that determines those limits. As a Boeing spokesman told the BBC last year when a European airline proposed a stand-up only route, "Stringent regulatory requirements—including seats capable of withstanding a force of 16 G—pretty much preclude such an arrangement."

What environmental changes can we handle?

Individuals vary greatly in how well they tolerate departures from normal atmospheric conditions, whether these are changes in temperature, pressure or oxygen content of the air. Bounds of survival also depend on how slowly environmental changes set in, because the body can gradually adjust its oxygen usage and metabolism in response to external conditions. But some rough estimates of our breaking points can be made.

Most humans will suffer hyperthermia after 10 minutes in extremely humid, 60 degrees Celsius heat. Death by cold is harder to delimit. A person usually expires when their body temperature drops to 21 degrees Celsius, but how long this takes to happen depends on how "used to the cold" a person is, and whether a latent form of hibernation sets in, which has been known to happen.

The boundaries of survival are better established for long-term comfort. According to a 1958 NASA report, people can live indefinitely in environments that range between roughly 4 and 35 degrees Celsius, if the latter temperature occurs at no more than 50 percent relative humidity. The maximum temperature pushes upward when it's less humid, because lower water content in the air makes it easier to sweat, and thus, keep cool.

Humans don't fare too well with abnormal oxygen or pressure levels. At atmospheric pressure, air contains 21 percent oxygen. We die of anoxia when that concentration drops past 11 percent. Too much oxygen also kills, by gradually causing inflammation of the lungs over the course of a few days.

We pass out when the pressure drops below 57 percent of atmospheric pressure, equivalent to that at an altitude of 15,000 feet (4,572 meters). Climbers can push higher because they gradually acclimate their bodies to the drop in oxygen, but no one survives long without an oxygen tank above 26,000 feet (7925 m).

Nausea is a common illness found while flying. It is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It occasionally precedes vomiting, but a person can have nausea without vomiting.

There are many causes of nausea. In aviation, it is caused by motion sickness. Motion sickness is one of the few areas where civilian desires overlap with military requirements, because it can effect both the common passenger and the trained pilot. A lot of data has been generated. In 1995, for example, British naval doctors subjected participants to repeated vertical and horizontal motions while the participants were either seated upright or lying on their backs, and determined that the subjects found horizontal movement while prone to be the most tolerable, and seated horizontal movement to be least tolerable. And a 2006 study established that low-frequency movement is more nauseating than high-frequency movement.

The accepted notion, proposed by the English physician J.A. Irwin in 1881 and largely confirmed by NASA in 1970, is that we get sick when our visual input contradicts our vestibular, inner-ear input, when what we see (an unmoving bulkhead) is in conflict with what we feel (sudden acceleration). This is why passengers get sick before drivers or pilots do.

"Pilots on the controls have a foreknowledge of the aircraft motion. For passengers, expectations of aircraft motion often conflict with actual motion, and sickness often results."

Figure 2.4 – Safe Zone graphs

Pushing the Limits of the Human Body

Even though the human, by structure, are fragile and cannot survive in many scenarios, we still strive every day to achieve new levels of performance. The human body is such a complex system, that sometimes it is hard to say what a man can and cannot do. Under pressure our bodies can show us how extraordinary they truly are. This complex machine grew out of millions of years of evolution. So intricate, we are still mystified by many of the things going on inside us.

Sight

Our sight relies on the most complex system of our bodies. It functions as survival sensors, giving us essential information at the crucial time. Using three quarters of our brain power when we’re challenged our eyes focus on the smallest detail at lightning speed. They allow us to see in the dark. Our brain allows us to see even while we sleep.

Just about every activity in our life involves our sight. It guides the human body. Many animals have different kinds of vision, but as humans, we can do it all. Like no other creature on Earth, our vision can distinguish around ten million colours, switch focus from infinity to mere centimetres in a fifth of a second, pinpoint detail regardless of light and have a field of view of almost 180 degrees. Seventy percent of the neurons in the brain in some way sub serve the visual system.

At the back of the eye most of the retina consists of millions of rods. These cells see no colour or detail, but if anything in our field moves, the rod spots it. This helps gathering essential information in demanding moments, when there are multiple events happening at the same time in our field of view and we have to take everything into account when planning our actions. When focusing at a single object, other cells at the mid retina act. A pin head size dot holds six million cells called cones. Their role is to percept colour and detail. Together, these two processes help focus where the vision is most needed whilst also monitoring other activities around us, drawing attention when needed.

But how do we know when facing numerous such activities, which require our focus next? Motion sensing rod cells switch off when they detect action that’s consistent or constant, so the brain tricks the eyes by scanning, forcing the eyes to lock on to small details. Taking all this information is hard work. Human sight has only two degrees of detail vision at the centre. To check the whole monitoring area, the human has to sweep, jumping from point to point for detail. Each jump is called a Saccade. The Saccade is the movement that the eyes make together when they are looking directly at one thing and all of a sudden they look at something else. We have mechanisms that wire the muscles that move our eyes to the image and we can quickly lock on to another image, all at once. Along with another skill called interpretation of detail, we can distinguish what needs our attention and what doesn’t at incredible speeds.

Another trait of the human eye is its adaptability to brightness. They have amazing sensitivity. In complete darkness from over sixty kilometres we can detect the light from a single candle. We rely on the rod cells which despite the fact that they detect only black and white, are highly sensitive. Though not as efficient as in the light, together with the photographic memory of our brain gathered from our lifespan, we can fill the blanks in our vision with objects we associate that might be there. For example, we can associate a box with black and white squares in the dark with a chessboard or a tall cylinder with a bottle. Our brain constantly makes assumptions when looking, but not fully seeing the object ahead. This helps us scan wide areas in a short amount of time and make rapid judgements.

There are many reasons why we have two eyes and are both placed frontally. Because of the distance between the two, the images each eye projects is slightly different than the other and that difference gives us a sense of distance between objects.

Strength

In a crisis, our bodies can accelerate fast, survive a crunching fall from the sky, lift unimaginable weights and drive ourselves mile after mile. Our muscles are made out of thousands of fibres, millions of filaments, the microscopic engines that power us all.

To prevent damage from external sources, our internal organs are protected by our bones. Our skeleton is made up of 206 bones. They are incredibly strong; their strength to weight ratio unmatched by any other natural material on Earth. Inside is a matrix of hollow cells, its walls are as thin as paper. Bone gets its rigidity from calcium and phosphorus, materials found in seashells and teeth. Also, almost half of our bone mass is soft and alive, allowing our bones to bend. Our rib cage can bend up to 2.5 cm. A thighbone can withstand almost a ton of stress before snapping.

Figure 3.2 – Thighbone on a hydraulic press

Every seven years a healthy human body completely replaces every single bone cell. This renewal keeps our bones incredibly strong and uniquely adaptable. “The beauty of bone is that it can change, in terms of its patterns, depending upon the stress that it sees in that particular area and there are geometric designs in the bone that prevent the bone from breaking with torsion, with compression, with different types of loads.” . Each individual’s bone structure is different, adapting according to each’s needs. For example, a runner grows stronger leg bones than a swimmer and a tennis player has bigger bones in their racket arm.

The human skeleton has evolved a material so strong that no technology can match it. Running puts a strain on our legs three times our body weight. To overcome this our legs have high-performance shock absorbers. A jump can put the skeleton under stress equal to ten times body weight, but the body has ways to handle such forces. On landing, leg muscles absorb energy so we don’t simply collapse. They key to such a feature lies within our knees. The knee bones are connected by ligaments, lengths of fibrous tissue that crisscross. As the joint flexes, they stretch. But ligaments are twice as tough as nylon rope, with a combined breaking strain of nearly a ton. At the joint’s core, between the two bones, lies the cartilage. A mere fraction of a centimetre thick, it absorbs the impact’s full force. Cartilage shapes the nose and ears and is made of collagen. But in our joints, cartilage has remarkable properties. A weave of collagen fibres is surrounded by eighty percent water. On impact it acts like a water-filled cushion. An average cartilage can bear up to seven tons before it gives way. What’s more, on the pad’s surface, collagen fibres are uniquely arranged to make it almost frictionless, the knee bones rolling over one another smoothly.

Figure 3.3 – “A weave of collagen fibres is surrounded by eighty percent water.”

We cannot control our bones, but we do have power over our muscles. In a daily routine, our body can only do so much for us, but when in crisis our body enters into overdrive through adrenaline rush, unlocking power we never knew we had before.

Muscle tissue works by contracting, pulling on bone, using it like a lever. These contractions occur microscopically. Each muscle has thousands of individual fibres, bundled like wires in a cable. As we age, muscles may get bigger or smaller, but we’re born with every muscle fibre we will ever have. Within each fibre are yet smaller filaments. To activate the muscle, chemicals trigger neighbouring filaments to ratchet together, intermeshing like locked fingers. As they slide past each other, the whole muscle fibre shortens. These contractions drive all our muscle movement.

Yet the big surprise is that most of us use only about a third of our muscle fibres at any one time, even when we feel we exert ourselves. It is the way our muscles deliver power most efficiently and most of us cannot consciously or voluntarily surpass that limit, but when we need a great amount of force, in a life-threatening situation or other emergency, our body synchronizes instantaneously, our brain activates all the fibres in our muscles at the same time and the result is a surge of power. We wouldn’t normally use our body to that extent because we risk ripping muscle from bone.

Our bodies have strength to override normal reactions, so we can ignore damage and keep going, but we only do this by drawing on a very special series of factors. Adrenaline along with training help the brain ignore the pain suffered and keep going. Damage to our bodies causes pain we all sense, but we differ in how we deal with it, how much pain we tolerate. “Where the difference is is not in pain threshold, but in pain tolerance.” .

Besides unlocking our body’s resilience, the mind can also unleash extraordinary speed. We instinctively call on that power when the brain spots a hazard too deadly to confront. Rather than face it, we push our bodies to the limit to escape. Like all other bursts of power, it is triggered by adrenaline. Just above the kidneys, glands inject the hormone adrenaline into the bloodstream. The adrenaline boosts the heart rate, which pumps blood to the muscles more quickly. Adrenaline signals the liver to flood the body with glucose. Another trigger is instant energy, which is stored in the muscles in case of emergency. This is called Adenosine Triphosphate. ATP is the energy molecule that keeps us alive. It fuels our muscles and it can be made by burning glucose or fat. We store an emergency reserve of ATP in our muscles, available for instant action, turbocharging us on demand for a few seconds.

through the nervous system to the muscles in a very organized, synchronised pattern. Not all muscles have the same number of controlling nerves. The body’s biggest muscles, in our legs, take orders from only five hundred nerves. These muscles have the most pulling power. The muscles responsible for the most complex and delicate procedures lie in our hands and are controlled by four thousand nerves. Each hand has twenty seven bones, thirty individual muscles, and more than one thousand six hundred kilometres of nerve fibres and blood vessels. Coordinating all this takes a lot of brainwork. Merely controlling our hands takes almost half of the part of our brains dedicated to movement.

A set of connections between brain cells governs every action, but we aren’t born with these connections. We learn them and maintain this strength throughout our lives. When we repeat a certain action enough times, it becomes a reflex, because it no longer requires the brain’s full commitment to it. This process is called automation. Without thinking, signals fly down to the muscles at more than a hundred meters per second and the move becomes automatic. Training for automation may continue even overnight. While sleeping, the skills practiced all day are reinforced as connections are strengthened in our brain. Same applies with studying, when during REM (rapid eye movement) sleep or dreaming sleep, your memories are consolidated.

To keep our muscles working over sustained periods require another strength, called fat. The average person has about two to three hours’ worth of energy. The brain detects low blood-sugar levels, which forces you to put a stop to your activity. To keep going, the brain has to trigger a new fuel source. When glucose runs low, we tap fat cells for reserve energy, but fat takes longer to process than carbohydrates, so shifting between the supply changeovers needs to be practiced in order to be used on a regular basis. This process also takes up additional oxygen, so to avoid fatigue abnormal stress is put on the heart to deliver the needed oxygenated blood to the muscles.

Locked inside us, a network of muscle and bone give us unparalleled flexibility, exquisite coordination and in a crisis, brute force and the speed to escape.

Sensation

Sensations keep us alive, letting us see, hear and touch our world. More than a million tiny sensors beneath our skin feed us raw data. Seventy kilometres of nerve fibres let us respond at incredible speed. Our sensations warn us of danger and are our first line of defence.

Each square centimetre of our hands holds 300 touch sensors. Some, near the surface, record the lightest of contacts. Others lie deeper and measure harder sustained pressure. Through a web of nerves, they fire signals to our brain. In fractions of a second, the brain signals motors nerves, triggering precise movement of our hands. Four thousand nerves direct each hand.

We seldom do not rely on our hands alone when doing something. When a pilot controls a helicopter, aside from maintaining a desired attitude through the use of his hands and feet on the controls, at the same time he must read data from a dozen instruments, watch the horizon and pay attention to the radio, as well. Amid all this, his sensory system must calculate and balance altitude, speed and position, as well as plan ahead his moves, outperforming any existing computer.

Another essential factor is the speed of signals in our nerves. The secret lies in the nerve structure. Our nerves are bundles of thin cells, some almost a meter long, carrying electrical signals to and from the brain. As insulation protects electrical wiring, a sleeve of fat surrounds key nerves and it is this fat layer that keeps signals from interfering with one another so they can transmit signals around our nervous system at speeds over four hundred kilometres per hour. Our nerves work so fast and our touch can be so precise that we can make tiny adjustments without thinking. By acting on instinct, we depend on sensations working faster than we can think.

This layer of sensors is not distributed evenly beneath our skin. Our hands have a hundred times as many sensors per square centimetre as the back of our legs. They are placed when we need them most. Our hands, feet, lips and tongue are most sensible to touch. Other senses have different patterns. Sensors for heat are most dense in our fingertips, nose and strangely, our elbows.

Even when we don’t realise it, these sensors control how our bodies function. When it gets hot, sensors and nerves work together to keep us cool, at about thirty seven degrees Celsius. This is doable thanks to hundreds of thousands of tiny heat sensors and the cooling system they trigger. When our skin heats beyond 34 degrees Celsius, sensors signals our brain. Its central thermostat uses other nerves to start the cooling process. Beneath our skin lie over a million tiny sweat glands. When we heat up, our blood vessels dilate, bringing blood and heat to the skin surface more quickly. The sweat glands extract water from the blood and release it into the open. As it evaporates, it cools us. Under ordinary conditions, we produce about one litre of sweat a day, but in extremes we pump out a lot more (more than two litres per hour).

The human body is seventy five percent water. To survive, our vital organs need their share of that fluid. Normally, we have enough to spare for the cooling system, provided we keep the body filled up. Losing as little as three percent of the body’s water can cause cramps, headaches, disorientation and even hallucinations. In response to the lack of water, the brain reacts by overriding the body’s thermostat,

Sensation tells us about the world around us, but under certain circumstances it can work the other way around. Our nerves tell the world about what is going on inside us. Our physical reactions can reveal what we truly feel, whether our cheeks are flushing with embarrassment, a voice choking with emotion or even different allergic reactions such as skin rashes. A polygraph, or lie detector, captures the signals our body transmits when we are lying to tell if we are telling the truth or not. When we are stressed, our network of nerves starts to prepare our body for action, as if it is under attack. It starts by triggering your stress hormone, adrenaline. Your heart rate increases to pump more blood to your muscles, as if you are about to act. Your breathing deepens, as vital oxygen reaches your muscles and you begin to sweat. The body cools so that you won’t overheat when rushed into action. The brain will not let us stop this survival strategy. These basic nervous functions are automatic, that’s why a polygraph can often uncover a liar.

Of all the sensations, the one most of us would rather not feel is pain, but pain is vital. It is there to protect us by alerting the brain to harm. Any injury triggers chemical reactions within pain sensors. They fire electrical signals into the nervous system that travel to the brain. Pain nerves work more slowly than others. Signals that convey dull, throbbing pain operate so slowly that we sense the delay between an injury happening and the pain it triggers. This delay gives us precious moments to escape the cause of the pain before the full effect overwhelms us. In the brain, pain works differently from other sensations. Other senses are processed in specific areas, but pain is processed in many different parts of the brain and the areas activated differ from one person to the next. “Pain is a perception. It is in the brain. It is the brain’s interpretation of an injury and that is the risen why it is so different among different people. Pain has an emotional component to the experience and it is the variation in the emotional component that will colour and alter the way a person perceives pain.” .

The pain sensors don’t run directly to the brain. They go via the spinal cord. As they enter the vertebrae, they pass through a gate. Buried in tissue with the consistency of jelly is the meeting of two nerves, known as a synapse. Jumping a tiny gap, the signal passes from nerve to nerve and on up the spinal column toward the brain. These junctions have a special property, they can be turned off. In extreme cases when the damage results in overwhelming pain signals, the brain orders the release of endorphins. They flow down to the junctions in the spinal cord, where they smother the synapse, stopping the pain signals from jumping across. The result, no sense of pain. These natural painkillers are stronger than morphine. By supressing the pain, the mind is free to assess the immediate threat without any distractions.

The body doesn’t always try to neutralise pain. Sometimes our nervous system makes us hurt more. The sensation of pain is often the only way we will know that or body is damaged. Pain serves as our central alarm system. Whenever our skin is broken, the body fights back quickly. First, it sends white blood cells to clean the wound. Then, the surrounding tissue swells, irritating nerve endings. The area becomes inflamed and painful. When an insect bites you, it is not the wound that hurts, but the body’s reaction to it. When the tissue inflames, it acts as a safety perimeter, warning us to protect the area or do something about it.

Pain can be terrible, but living without the sensation can be even worse. Diabetes is a disease that leaves too much sugar in the blood. Excess blood sugar can damage nerves, leaving parts of the body unable to sense touch, temperature or discomfort. If you can’t see an injury or feel it you won’t know you need to treat it. Anyone without the nerves to transmit the sensation of pain must be extra careful. The smallest wound could become infected, with inflammation spiralling out of control before the patient realises it.

Subtle pain signals constantly alert the body to make adjustments, otherwise we would stress bones and blister skin. The nervous system is essential to who we are. Without sensations like pain, our bodies would soon fall apart.

Aside from the body’s reaction, there are other ways to which you can bypass the pain. Hypnosis is one of them. By using it, one may enter into a deep slumber during surgery and interpret the pain it experiences as pleasurable, even after the operation ends and the wound fully recovers. Though you cannot hypnotise yourself, there is another way to suppress it and that is through meditation. By meditating, you change how your body works. Your heart slows, pumping less blood. The muscles relax. Relaxed muscles means less tension, which means less pain, but the strangest effect occurs in the brain. Although the brain is still alert, meditation lessens the emotional reaction to pain, so when pain sensations hit, they have little effect.

Figure 3.6 – Endorphins smothering the synapse to block pain signals from crossing

The human body is quite literally a bundle of nerves. They transmit sensations that keep our bodies in harmony. They give us pleasure and alert us with pain, always at the ready to trigger our bodies into action.

Brain Power

At the top of our spines rides almost one and a half kilograms of tissue controlling everything we do. Our brain works faster than any computer, processing an astounding one hundred trillion instructions every second. To save our lives, it can slow down time, tell us what to eat, even when to consume ourselves and as we sleep unleash immense power. Our brain drives our muscles and steers our lives.

Deep in the brain two parts, inch two point five centimetres across, make up the control centre. It manages our fight-or-flight response hardwired by evolution. It drives us to act without thinking. The control centre collects information from the outside. Normally, the data goes to the brain’s thought centre for study and reflection, but in emergencies, the control works differently, signalling nearby areas that make up the disaster centre. Without a thought the human’s brain commands them to act immediately, on instinct. The disaster centre engages automatically. It orders release of the natural stimulant called adrenaline. Heart rate increases, blood being redirected from nonessential tasks like digestion to parts of

Our brain controls every decision we make, even our taste in food. Our urge to eat resides deep in the brain. A small lump of tissue is the brain’s want centre (the Hypothalamus). No organ is hungrier than the brain. It consumes nearly one fifth of the energy we take in, but the want centre responds of the whole body for nutrients, including vitamins and other minerals. When the body runs short of anything, the mind drives us to fill the gap. When our want centres realises we are missing something in our diet, it generates intensive cravings, driving us to eat anything to satisfy them. This survival instinct forced our ancestors to try anything to keep their diets in balance to the point of overriding taste. A man stranded in the middle of the ocean had nothing else to eat, but fish. Although rich in protein, fish’s flesh lacks vitamins and minerals that the human body needs. What he did not know is that the fish he caught contains the nutrients he needed. They were in parts that he usually discarded, such as the skin (Vitamin B), spine (Calcium and Phosphorus), eye (fresh water), liver (Vitamins A and B), liver oil (Vitamin D and Omega 3 Amino Acids), gut/stomach (Vitamins A and D) and roe (Vitamins C and B). As his body was about to shut down, he became more and more interested in the fish’s parts than the flesh itself.

response, the brain releases endorphins, natural painkillers that induce sensations of pleasure, as explained in the previous chapter. The chilies’ heat activates the brain’s learning centre. It stores the memory that despite a fierce flavour, chilies are rich in nutrients and a peculiar pleasure. Coming back to the stranded man, triggering a sensation of pleasure whenever he digests needed nutrients, his brain transformed fish parts that once disgusted him into delicious treats.

The brain’s power over diet is core to our survival. So powerful that scientists have tested it against one of the strongest human urges. They fitted volunteers with electrodes to record brain activity. Then they compared how our pleasure centres respond when we eat chocolate and when we kiss.

Figure 3.9 – Kissing vs. Eating Chocolate

Not surprisingly, when couples kissed, their pleasure centres reacted, but kissing could not touch the effect achieved when chocolate hit the tongue. That pleasure was more intense and lasted longer.

Our obsession with eating makes perfect evolutionary sense. During most of human history, food has been scarce. That experience drives us to gorge when we can and store nutrients for survival, but even when food runs out completely, our brain has a response. The want centre, buried at the brain’s base, has instructions for beating starvation. In animals, this part of the brain evolved around the time of the dinosaurs, before mammals existed. To drive our search for food, our brain first releases a hormone called orexin. Orexin comes in tiny does, but has a profound effect. This hormone makes us more alert, improves our muscle efficiency, making us better hunters and even sharpens our problem-solving skills. When completely out of supplies, our bodies become even more efficient by slowing down. It lowers our

and start ripping apart protein from our muscles. “A typical non-obese individual would have 130000 to 160000 calories stored as fat, only about 54000 calories stored in muscle and only half of that 54000 calories is available for energy because once you have lost half of the protein in your body, it is no longer compatible with life.” .

The brain works flat-out at all times, digesting reams of information. As an air traffic controller, it manages thousands of systems that keep us alive and it has to do that faster than any computer could, processing an astonishing one hundred trillion instructions every second. As any central processing unit does, the brain produces heat. Without cooling, our brain would overheat. Its internal temperature is rising almost one degree every five minutes. Ten minutes without cooling causes disorientation. Twenty minutes can do permanent damage and after fifty minutes if the brain is six degrees too hot you are dead. Because our brain manages everything else, its main duty is to protect itself. Our body’s cooling system works similar to a car’s. A car cools itself with water, but the brain uses blood, which carries heat to the skin’s surface. As sweat evaporates, it cools the blood. The forehead and face are the best sites for cooling. They have many sweat glands and air can get at them. The rest of the body is harder to cool. We still do not know exactly how our brain maintains the correct temperature under such conditions. One controversial theory says it has an extra cooling method. On the way to the heart, blood cooled by a sweating face and forehead runs close to arteries feeding the head. That lowers the temperature of blood bound for the brain. Considering the brain’s almost twenty thousand kilometres of blood vessels, this may be how the core stays at optimum temperature. It is also important to stay cooled because it helps us focus more at the task at hand without being distracted by the body’s overheat.

Of all that goes on in the human brain, the biggest mystery surrounds the time when we sleep. One surprise is that at night our brain is as busy as during the day. The brain’s first job is to put us to sleep. As night falls, a dot-sized gland in the brain, called the Pineal gland, triggers release of our natural sleeping pill, melatonin. Acting on our central nervous system, melatonin makes us drowsy, but as the body slows, the brain goes to work. Brain cells that have worked all day shut down for repair. Chemicals clean up the by-products of brain cell activity and in some parts new brain cells grow. Without this internal diagnostic and repair service, the brain could not maintain peak performance. If we stay awake too long, our brain knocks us out, no matter what the consequences. After being awake for a prolonged time, sensing a crisis, the brain begins damage control. It shuts down areas not key to vital body function, including the thought centre, the seat of logic. That is when you start hallucinating. Staying even longer awake and the brain eventually puts you to sleep by force, no matter the circumstance.

Even as we sleep, the part of the brain that hears remains alert, which is why alarm clocks and other noises wake us. It is the body’s natural defence mechanism which keeps us in contact with the outside world. In aviation, being rested at all times is crucial, not because the lack of sleep might kill you, but it makes you susceptible to mistakes which can lead to accidents.

wildly in time to our dreams, hence the term “rapid eye movement” or REM sleep. During REM sleep, our brain grows so busy that blood flow to it nearly doubles. So that we cannot act out our dreams, our brain sends signals to the spinal cord, temporarily paralyzing our limbs. It may feel as if we dream all night, but we dream in bursts, a few minutes at a time, yet in a lifetime, we will spend six years dreaming.

Dreams do more than entertain our brain. They are part of the job of storing memories. Only at rest can the brain sift the day’s experiences, discarding useless details. Events occurring while we are awake are only stored in temporary memory. In dreams, we discard irrelevant material and file useful information into permanent storage. But with no logic to impose order, thoughts can collide, unleashing creativity, generating fresh ideas. This may explain how some great minds work. Einstein’s dream of traveling on a sled at the speed of light influenced his theory of relativity. Nobel Prize winner Niels Bohr revolutionized physics when a dream of horses offered a clue to atomic structure and artist Salvador Dali described his surreal work as hand painted dream photographs.

While dreaming, NASA designer Bruce Damer discovered how to build a permanent moon base. After focusing on several issues for many months, such as how do you shield astronauts from radiation and how to have them use local resources out of the lunar surface, he found his answer in his sleep. Robots, sent in a space vehicle, could land on the moon and build a base, even before astronauts left Earth. When he woke, he began sketching and the people at NASA liked the idea.

The challenge is not to leave the dreams to chance. We may be able to harness the sleeping brain’s power by using a technique called lucid dreaming. The key is to learn how to know that you are dreaming without waking. The next step is to take the dream where you want it to go. Managing dreams may be the only chance we get to influence what is normally out of our control, our brain.

There is no more complex and mysterious organ than the human brain. It runs our lives, conscious or unconscious, often pushing us in directions of its own choosing. It is a journey to scientific exploration that could unlock potential we cannot yet see, pushing our bodies to new limits.

Stress

Stress is defined as "any event which may make demands upon the organism, and set in motion a non-specific bodily response which leads to a variety of temporary or permanent physiological or structural changes".

The simplified version of the definition above made by Richard S. Lazarus (commonly accepted definition) states that "Stress is a condition or feeling experienced when a person perceives that demands exceed the personal and social resources the individual is able to mobilize." .

Everybody’s experiencing stress one way or another. We need to see where we are on the stress continuum, whether we are in a low stress situation where we have done things a thousand times, we have well learned and are well adapted to the job and so we are not paying as much attention to what we are doing as much as we should, through to extreme stress where we might not be operating at full capacity because the work load is too high, your focus is needed in several places at the same time and cannot keep track of one place continually. It’s a matter of recognizing when the pressure is on and dealing with it. People often juggle between personal endeavors, workload and fatigue and that contributes to stress on the job.

In aviation, accidents almost always occur like a domino effect, in a sequence of mistakes that are made. Stress is the triggering factor that starts this domino into causing the effect. In order to maintain safety in aviation, at least one of these dominos must be removed to avoid a tragic accident. This is where all of human factor studies and hard work can come into play. Depending on what particular job a person is performing in aviation, they must take steps to avoid stress. Stress can be avoided by taking steps to relieve other possible factors. Physical factors such as eating a balanced diet, getting plenty of rest and drinking plenty of water while exercising regularly will help the body resist fatigue and stress. Mental factors are equally as important. Knowing one’s job well and being confident in the execution of job duties will equally reduce stress. The equilibrium of physical and mental factors does not completely destroy the stress factor, but it will make it manageable and thus safer for everyone.

There are two different types of stresses: they can either be good (Eustress) or bad (Distress). Eustress can harness better performances and provide the boost for aviation personnel to achieve the task, to train harder to improve their standards to become the best in their job. Distress, on the other hand, affects people by pulling them down, causing them to lose focus doing time critical tasks in their area of work, thus leading to accidents. These are manifested by loss of spiritual awareness, poor decision making, becoming confused, making errors of judgement, unable to cope with increase in workload and even miss from work.

For pilots and other crewmembers, even under ordinary conditions, the flight environment includes stressors such as noise, vibration, decreased barometric pressure, and accelerative forces. Fatigue and altered sleep-wake cycles also may be factors, especially for crewmembers on flights that span several times zones. Moreover, a 2000 study found that the captain’s personality type also influences the amount of stress on the flight deck. During the study, 24 three-member flight crews performed line operations, including emergency operations, in a Boeing 737 simulator; afterward, they were tested for perceived stress. The crews that committed the fewest errors reported experiencing less stress than crews that committed more errors. The crews with the fewest errors typically were led by captains who were categorized in the report on the study as possessing the “right stuff” (for example, they were described as “active, warm, confident, competitive and preferring excellence and challenges”). Other captains were categorized as possessing either the “wrong stuff” (for example, they were described as arrogant, authoritarian, emotionally invulnerable, impatient, irritable, preferring excellence and challenging tasks, and having limited interpersonal warmth/sensitivity) or “no stuff” (for example, they were described as “unassertive and self-subordinating, with average interpersonal skills, low self-confidence, low desire for challenging tasks and low desire for excellence”).

Aviation maintenance is a stressful task due to the fact that aircraft make money flying instead of being tended to in the hangar; hence there is an enormous amount of pressure on maintenance personnel when it comes to finishing the task in the shortest time possible and get the aircraft back to flying without facing any delays or cancellations. Whilst doing the job, there are also many things to be careful about in terms of using the correct tool, installing the correct parts whilst working in dark tight spaces. The stress can be self-imposed by increasing one's expectations of themselves and working harder than necessary to complete the job in the required time frame. The stress can also be from the manner or method that a manager uses to organize the employees. By not having the "people" skills to effectively communicate information or tasks to the engineers on the hanger floor, the manager risks stressing the engineers out by a lack of information.

ATC (air traffic control) is a highly demanding job with high stress levels due to the complexity involved balancing the controlling and resolving conflicts of numerous aircraft in an efficiently, expeditiously and safe manner whilst also taking into account factors such as weather development and aircraft emergencies. Due to this complexity, controllers require high cognitive capacities which include prioritizing, movement detection, spatial scanning, image and pattern recognition, visual and verbal filtering, inductive and deductive reasoning, short- and long-term memory, coding and decoding and probabilistic and mathematic reasoning.

Causes of the stress are known as stressors:

Physical Stressors

These stressors add to the personnel's workload and make it uncomfortable for them in their work environment:

Temperature

High temperature build up in the cockpit/hangar increases perspiration and heart rate causing overheating of body.

Low temperature build up causes the body to feel cold, weak and drowsy.

Changes in air pressure due to turbulence exerts unusual g-forces on the body and makes it difficult to control the aircraft.

Vibration transmitted to the body from the aircraft via the seat makes it difficult to read navigational charts and instruments.

Noise levels in a typical cockpit are in the range 75-80 db. Anything above this causes stress and makes it difficult to concentrate and forces the pilot to have to strain to hear ATC instructions. Noise levels in the hangars are also high due to hangars situated near aircraft taking off and landing, making it difficult for maintenance personnel to focus and concentrate.

Poor Lightings at their work area make it difficult to read technical data and manuals whilst working on the aircraft and the use of torchlights are also inadequate, increasing the propensity to miss something important.

Confined spaces also render maintenance personnel difficult to perform their tasks as their bodies are sometimes contorted in unusual positions.

Poor visibility due to heavy fog and traveling in instrument meteorological conditions

Psychological Stressors

Work related stressors prior to the mission can increase arousal due to apprehension but too much can cause over-anxiousness and failure to perform up to speed. I.e. in ATC, envisioning handling multiple aircraft and making sure all are out of conflict and safe in the most expeditious manner.

Financial problems such as impending bankruptcy, recession, loans and mortgages to pay.

Marital problems due to divorce or strained relationships due to persistent quarreling.

Interpersonal problems with superiors and colleagues due to miscommunication or perceived competition and backstabbing.

Physiological Stressors

Flying when unwell resulting in the body using more energy fighting the illness and hence less energy to perform vital tasks.

Not having proper meals also result in not having enough energy and induces symptoms like headache and shaking.

Lack of sleep; Fatigued, the pilot is unable to maintain performance standards for long periods as he is struggling to stay awake due long working hours

Conflicting Shift Schedules affect the body's circadian cycle and lead to a degradation of performance.

Working long hours without any break especially at busy airports when handling multiple aircraft departing and arriving on intersecting and parallel runways.

However, it is to be noted that a particular situation can bring about different degrees of difficulty for different people. The situation can be a stressor for one person and "normal" for another. Also, the stressor can cause stress in the same person when he is in a different predicament i.e. stressors which he has usually kept in checked suddenly is overwhelming him now due to perhaps increasingly turmoil in the family.

Handling Stress

People cope with stress in many ways. Specialists say that the first step in coping is to identify stressors and the symptoms that occur after exposure to those stressors. Other recommendations involve development or maintenance of a healthy lifestyle, with adequate rest and exercise, a healthy diet, limited consumption of alcoholic drinks and avoidance of tobacco products. Prom a physical point of view a person should maintain good physical fitness, have regular meals, have sufficient sleep, sound time management and control the physical environment. From a psychological point of view a person should have sound preparation with regard to knowledge, skills and procedures, have confidence in your training and ability, have a well-balanced social, family life so that financial, domestic worries are not a problem, share and discuss problems so as not to bottle them up and solve problems as soon as possible to prevent snowball effect (a snowball effect is a term used when a small error left unattended leads to bigger problems).

Stress Management

Stress management is an important skill for aviation personnel to hone so that they adequately cope with stress and prevent it from overwhelming their ability to respond properly at work.

Recognize the potential signs and symptoms of stress

Be proactive in removing the cause of stress i.e. turbulence in extreme weather by terminating the mission, according more priority to the emergency aircraft first before controlling other aircraft

Removing yourself from the stressful situation by knowing one's own capability ie give up aerobatics learning and try something else if it is too much to handle, calling out for help from colleagues if in a very complex ATC scenario

Prioritize actions in the cockpit i.e. handling the emergency vs chatter on radio telephony with ATC

Do not be over focused in finishing the mission regardless of the situation i.e. impending weather, impeding deadline in completing the maintenance task

Be current with all existing procedures and familiar at the workplace

Rendering the correct supervision by providing feedback to management if the deadline is impossible to attain

How does Stress Affect Performance?

The relationship between stress and performance has been portrayed by the stress response curve created by Nixon P. in 1979. In addition, pressure, an important stressor, has also a crucial influence on an individual's response to stress.

One of the most noticeable effects of stress in one’s life is the changes in his performance. While we can easily recognize the consequences of normal or excessive amounts of stress through mere observation, it’s best to learn about the scientific relationship between stress and performance.

overwhelming or excessive, the person reaches a fatigue point wherein the performance levels starts to decline. The ultimate end of overwhelming stress, called burnout, can be exhaustion, ill-health or breakdown.

Positive Effects

As shown by the graph, performance levels increase when stress management is effective. Stressors such as pressure and demands can facilitate better stress response and thus, higher levels of performance. For instance, a basketball player tries to run faster, shoot a three-point shot and succeeds in it because of the pressure he has obtained from the audience, the close scores and the tough opponents. Another example is the short but adequate deadline given to an employee, which motivates and encourages her to work actively and efficiently on the project assigned to her. Yet another instance is an approaching major examination which leads a college student to double time on studying and reviewing of lessons.

Negative Effects

When stress is perceived as uncontrollable or unmanageable, the person begins to experience a gradual to drastic decrease in performance levels, causing a decline in productivity and enthusiasm to respond to the stress. For instance, a very tight deadline is given to an office employee who has to take care of her four children at home and a sick mother at the hospital. This overwhelming mix of situations, if not managed carefully and totally, will result to a poor performance at work, bad relationships with other members of the family, ill health, and burnout.

Pressure and Performance

Pressure, one of the significant life stressors, affects performance, as shown by the “Inverted-U” graph below, which was created by Robert Yerkes and John Dodson in 1908.

Figure 4.3 – The Inverted-U Relationship between Pressure and Performance

Looking at the left side of the graph, you will notice that low pressure or low levels of stress results to s person’s stress response as “boredom” or unchallenging. Even if the task is of great important, in the absence of an appropriate level of pressure, attention and concentration to perform the task are significantly low. On the other hand, extreme levels of pressure doesn’t mean high performance levels; rather, it’s the same as the result from low pressure – low performance levels due to “unhappiness” or negative feelings due to overwhelming stress. However, there’s a region called the “area of best performance”. In this region, moderate pressure resulting to optimum stress or stress that is totally manageable leads to the highest level of performance.

Program: Creating a dynamic workspace based on stress tolerance levels

The main concept that needs to be understood is that everyone is born different. Although some people may be more efficient than others in a certain field, stress due to factors prolonged activity, high volume of work or even personal affairs may put them behind other less capable people, but with the stress tolerance required to fulfil the demanded job.

Today, most workplaces have a fixed schedule which is made as a mean of work hours an average employee can sustain without dramatically decreasing performance. The following program represents a new approach to creating work hours, based on evaluations that make up an individual’s level of tolerance and puts them to work in an environment best suited for his capabilities. People with a high rate of stress tolerance will work for less hours in the most demanding time of the day, whilst others will work for the remaining hours (supposing there are two shifts per day) where the workload is lighter. Work plan within the shifts will also be modified, based on the same parameters.

Evaluating individual’s stress tolerance levels

Before running the program, an evaluation must be given to the employees to determine their stress tolerance levels. Because we will be focusing on the ATC field of work, the “exam” for the controllers will be much similar to the ones they took when they applied for the position, more precise tests focused on logic and attention to detail. An example of such test will be added at the end of the paperwork. It will be timed (no more than 30 minutes) and will be given twice a day (at the beginning and end of the shift) for a week. An average of ten evaluations will make up the final result (considering the actual shift of 12 hours work and 24 hours stay). That result, along with other factors such as age, experience and position will make up a score and that score will be the individual’s stress tolerance level.

Because other factors, aside from the workload, may affect the result (such as personal affairs), the evaluation will be repeated every six months. This will give another chance to controllers to prove their real value.

Aside from the trade-off you get from this (better results for less work hours or lesser results for less workload), the evaluation results may be used as a reward system. By having good scores for a prolonged amount of time, that score may be further used when in question about getting a raise or even a promotion. The evolution on an individual’s scores throughout the years may help in determining the actual situation of a controller, if he is decreasing or increasing performance, if he lacks motivation or other factors. All these contribute to better managing the manpower and making sure the right people are put in charge when they are most needed.

The total score will be calculated as follows:

60% average score at the end of the week’s evaluation (three points per question)

10% experience (one point for every year since you started that position)

15% age (you get all points if you’re under 30, you lose one point for every two years over)

15% given by the supervisor for all other contributing factors (motivation, peak performance, acknowledgement of contributing factors during evaluation)

Compensation for continuously improved score will depend on the operator in charge.

Entering the requested details in the system

After everyone has a respective stress score it is time to enter them into the system. When the system starts you have the option to either add a person or initialise the program.

Figure 4.4 – Add/Run Window

Selecting the “Add Person” button will allow you to add a controller to the system. The computer only needs the First Name, Last Name and Score, as shown in the picture below.

Figure 4.5 – Input Window

After you write the required information you can either add the person to the list by pressing the “Add” button, or you can close this window by pressing “Cancel” in case you change your mind. Pressing either button will return you to the previous window.

Any number of people can be added to the list, but the default maximum number is 18. If the number of people entered reaches the cap, the “Add Person” button will grey out and will no longer be available to press. Supposing all 18 slots were filled, the program may start by pressing the “Run” button.

The following table will appear:

Figure 4.6 – Controllers’ Shifts Table Window

The full list can be seen by scrolling down using the bar to the right. The first two columns represent the names of the controllers. The third column represents the shifts they will be taking, in groups of 6 and the last column represents whether it’s a day or night shift, represented short by its initials. Notice that the score is not visible in the table, because the computer already computed their shifts with regards to the score, hence the score is no longer necessary.

Figure 4.7 – ATFCM

The grid represents the traffic flow of aircraft at LROPTMA (Henri Coandă Bucharest Terminal Maneuvering Area) on a regular working day on the first day of summer (transposed into grid from Eurocontrol’s Air Traffic Flow and Capacity Management publication (ATFCM)). Assuming this is the average traffic for the next six months, we can rewrite the controller’s schedule for that period. The horizontal axis represents the time in a day (in hours) and the vertical one represents the amount of aircraft entering the airspace at that time. The straight blue line represents the current shifts at ROMATSA (Romanian Air Traffic Services Administration) for the TMA (Terminal Maneuvering Area) of Aurel Vlaicu (LRBS) and Henri Coandă (LROP) airports (from 7AM to 7PM and from 7PM to 7AM). Taking the current traffic into consideration a new set of schedules, represented by the green and yellow lines, is applied. First we calculate the total amount of aircraft flown in that sector in a day (in this case 191). Then we try to find an interval in which about two thirds of these aircraft fly in 11 hours (in our case it is between 9AM and 8PM with 122 aircraft). This interval will become the day shift for those with the top 9 scores (the first half). For the rest, they will have the extended night shift (from 8PM to 9AM) where they will deal with less aircraft (69 aircraft). When working the opposing shifts, they will do the regular 12 hours (from 9AM to 9PM and from 9PM to 9AM).

The goal of this concept is to better manage the human resources such that more stress tolerant people work in the most demanding part of the day (in exchange for less hours) whilst others work in a less demanding environment for the remaining hours.

Because less tolerant people end up working more hours in the day shift than the more tolerant ones and vice versa, the program also modifies their timetable within their respective shifts. Before we go into more detail, though, some insight on the controllers’ roles within their shifts must be made.

Ideally there are three controller positions for each flight sector. In our example with LROPTMA, overseeing this airspace is a Planner, an Executer and an Assistant. The planner which, as the name suggests, is responsible for foreseeing the flight routes for the inbound and outbound aircraft, with respect to the traffic, weather or other conditions. The executer is responsible for maintaining constant contact with the aircraft in his airspace, guiding them and assuring a safe and fluent flight for everyone. The assistant is responsible for overseeing the entire operation of the other two, being an “extra pair of eyes” in case anything slips by and causes a chain of events. Any other controller responsible for the same airspace will be on call for the time being or on “Break” until the others finish their first round and they can change places.

We will order these three roles by difficulty, starting with the executer which is the most demanding, followed by planner which is less demanding and ending with assistant which is the least difficult to perform. If we were to represent their difficulty in numbers, executer would have 3 (out of 3), planner would have 2 and assistant would have 1. On call will be considered of no difficulty (0) because it does not demand anything from the controller.

Coming back to our goal, we must arrange these internal timetables in such a way that we can make the job less stressful for less tolerant people during peak hours, but compensate for the ease of work during the other part of the day. By selecting a certain shift and pressing “Details”, its detailed timetable appears. By pressing “Close” the mentioned windows closes and returns to the previous table.

The table below represents Becky’s dayshift timetable, Becky being the most stress tolerant of them all.

Figure 4.8 – Becky’s Timetable

Because Becky has a good stress tolerance level, she will be working eleven hours in her dayshift (starting at 9:00 and finishing at 20:00). The next image represents Freddy’s dayshift timetable, which starts at the same time as Becky does, but because his stress tolerance level is much lower than Becky’s, he will be staying the regular twelve hours a shift has (until 21:00).

Figure 4.9 – Freddy’s Timetable

Although Freddy has a dayshift longer than Becky, despite his inferior score, notice that his positions are overall less demanding than Becky’s. For better accuracy, we apply the criteria mentioned above regarding position difficulty to calculate the total “points” of difficulty for each:

Becky = Assistant + Break + Planner + Break + Executer + Break + Executer + Break

= 1 + 0 + 2 + 0 + 3 + 0 + 3 + 0

= 9 points

Freddy = Planner + Break + Assistant + Break + Planner + Break + Assistant + Assistant

= 2 + 0 + 1 + 0 + 2 + 0 + 1 + 1

= 7 points

In conclusion, even though Freddy spends more time at work than Becky, his work will be much less demanding for the time being. Notice, also, that he has two consecutive assistant positions. Although in general every position a controller fills must be followed by a break, assuming the position of assistant may be followed by another identic position on occasion, because it is not considered a very demanding job. Two consecutive breaks may also occur if there is no need for that particular person at that time.

This rule of 9 vs. 7 points apply to all timetables (higher stress tolerant people will have a job worth 9 points of difficulty on their dayshift and less stress tolerant people will have a job worth 7 points of difficulty on the same shift).

The opposite applies on the nightshift. The following picture represents the timetables of a more stress tolerant and a less stress tolerant controller working in the same shift (in the mentioned order).

Figure 4.10 – Fred and John’s Timetables

The figure to the left represents Fred’s timetable (which has a high stress tolerance) and to the right is John’s timetable (which has a low stress tolerance). Because the job is less demanding during this time, the less tolerant controllers can compensate for the less demanding jobs they have in their dayshifts. Making the same calculations as above, Fred will end up with a job worth 7 points of difficulty, as opposed to John which has 9 points. Like in the dayshift, but opposite, the less stress tolerant controllers will work on a shift worth more points of difficulty than the more stress tolerant people to compensate, but that will have a much lower impact due to the dramatic decrease of air traffic present at those hours. As mentioned at the beginning and seen in the picture above, John will be working an extra hour, as compared to his counterpart to fill the void made by the high stress tolerant controllers.

There are twelve different timetables the program generates (six for each category) and are arranged such that the same controller doesn’t have the same dayshift or nightshift timetable twice in a row. Being always flexible is key to obtaining the best results.

As an end’s note to this chapter all fields can be fully edited. Keep in mind that this program is an ideal representation of a day’s work, which is rarely the case. Employees might be missing for various reasons, other might not be fit to have a full shift that day or there might be more or less controllers active than the program’s default number. By leaving the tabs editable, the supervisor may alter the timetables and shifts as he finds fitting. Future developments may include algorithms that helps ease the supervisor’s work when it comes to changing schedules, but there can never be a program that fully anticipates every outcome.

Pushing Our Limits Through Technology – The G-Suit

Earlier we discussed about the human boundaries, the physical limits of our bodies and minds. The human body alone has countless hidden strengths and processes that help us survive and perform better in various situations, but even that has its limits. In our ever growing thirst for discovery and evolution we managed to build aircraft that easily fly faster than the speed of sound and spacecraft that take us beyond our atmosphere, but are we physically capable to simply board them and fly?

The G-Suit

What is G? For a given mass the force generated is directly proportional to the acceleration of the mass (Newton's Second Law of Motion). The ratio of the acceleration of a body to the gravitational constant (9.81 m/sec2) is the ‘g’. Thus a body which has a weight of one kg at one G will weigh five kg when exposed to an accelerative force of five G.

The G-suit, also known as the anti-G suit, is a flight suit worn by aviators and astronauts who are subject to high levels of acceleration force (also known as g-forces). In short, it is designed to keep your blood level in your brain stable whilst being subjected to high levels of acceleration in order to avoid a G-LOC (G-induced loss of consciousness).

In 1917 the first signs of this issue started to rise, when documented cases of pilots with loss of consciousness due to G-LOC were referred to as “fainting in the air”. Due to Professor Frank Cotton who described a new way of determining the centre of gravity of the human body which made it possible to graphically record the displacement of mass within the body under different conditions such as rest, respiration, posture and exercise. It wasn’t until the late 1930s when the higher speed monoplane fighters were build, when the issue became more severe. As a solution in 1940 some German aircraft had foot-rests above the rudder pedals so that the pilot’s feet and legs could be raised during combat in an attempt to minimize the negative effects of high speed turns.

When faced with high acceleration forces, depending on direction the brain may be overflowed with blood (-Gz) or almost deprived of it (+Gz). Assuming the latter, the pressure of the blood in the vessels above the level of the heart is decreased whilst the pressure below the heart is increased and the blood moves from the upper to the lower parts of the body. If the blood leaves the brain, it may lead to temporary hypoxia. Hypoxia is manifested by first dimming the vision, also known as greyout or brownout, followed by tunnel vision. At about +4.5 Gz the pressure in the arteries supplying the retina of the eye falls below the pressure within the eyeball (20 mm Hg), blood flow to the retina ceases, and loss of vision, termed blackout, follows in about 5 sec. At +5 to +6 Gz the blood flow to the brain of a seated, relaxed individual ceases, and unconsciousness occurs in about 5 sec (G-LOC). The pressure of the blood in the vessels above the level of the heart is decreased whilst the pressure below the heart is increased and the blood moves from the upper to the lower parts of the body. Although you will regain consciousness as soon as the g-forces stabilize, it requires some time to recover and a period of disorientation occurs before regaining full strength. This can be fatal to pilots who are in the middle of combat or at low altitudes.

Much less common in flight is for a pilot to be exposed to –Gz which forces the blood towards the head. –Gz is produced by simple inverted flight and outside loops and spins. Tolerance of –Gz is much lower than tolerance for +Gz acceleration. Thus exposure to –2 Gz causes severe discomfort in the head, and is followed usually by a severe headache which persists for several hours. Exposure to –2.5 G for only a few seconds causes rupture of blood vessels in the skin of the head and neck and on the surface of the eye. It frequently causes bleeding from the nose. The increased pressure in the arteries of the neck acting through the carotid sinus baroreceptors causes very marked slowing of the heart and often produces loss of consciousness.

The ranges of accelerative forces to which the occupants of aircraft and space vehicles may be exposed in flight and the durations for which these forces may operate are extremely large. Passenger aboard an airline aircraft are exposed to accelerations of 1.2 to 1.3 G sustained for several seconds during take-off, landing, or tight turns. On the other hand, pilots of modern combat aircraft are exposed to up to 10 G for several seconds. Astronauts on-board a space vehicle which is orbiting the earth are exposed to microgravity (0.0001 to 0.00001 G). As the saying goes for drivers “Speed has never killed anyone. Suddenly becoming stationary, that's what gets you.” , aircraft crashes will expose occupants to accelerative forces of the order of fifty G or greater.

The effect of the accelerative force upon the body does not depend solely on the magnitude of it, but also on its duration and direction in which is applied. We may say that the acceleration is of short duration if it is less than one second, when the main determinant of the effect is the structural strength of the body or of long duration when the forces of acceleration act for several seconds and may lead to sustained distortion of tissues and organs or alterations in the distribution of blood within the body.

Common aircraft manoeuvers like pulling out of a dive or coordinated turns apply an accelerative force parallel to the longitudinal axis of the seated pilots, resulting in tissue displacement towards the feet (+Gz). At +2 Gz the soft tissues of the face produce a sagging effect due to increase of weight; at +3 Gz it is impossible to stand up; at +7 Gz you become unable to raise your limbs or head, but even at +9 Gz you are still able to perform accurate movements of the fingers if the hand and forearm are well supported.

A G-suit does not necessarily increase the G-threshold, but it helps sustain high G longer without excessive physical fatigue. Whilst most people tolerate around three to five G, the G-suit will typically add one G of tolerance to that limit. In older fighter aircraft, the G limit was considered to be six G, but with the newer models nine G or even more can be sustained structurally, making the pilot fall behind in “tolerance” and increasing difficulty in maintaining high manoeuvrability in close aerial combat.

Training must still be done, as pilots practice several procedures to maintain the blood pressure at head level and hence consciousness and vision, on exposure to high G-forces. Raising the feet, a technique used in the Battle of Britain, will raise tolerance by about 0.5 G. Reducing the amount of blood which pools in the lower limbs and abdomen by applying counter-pressure to these regions by a G-suit will increase tolerance by 1–3 G, depending upon the area of the lower body covered by the G-suit. Raising the pressure in the chest, either actively by performing a hard expiratory effort against a closed glottis, or passively by means of positive pressure breathing, can greatly increase tolerance of +Gz by raising the arterial blood pressure. When active expiratory effort is employed it must be interrupted by taking a rapid breath once every 3–4 seconds, to allow blood to flow back into the chest to the heart and to maintain respiratory gas exchange. The pilot also tenses the muscles of the trunk and limbs while performing this manoeuvre, which is termed the Anti-G Straining Manoeuvre (AGSM). The AGSM together with a G-suit will increase the tolerance to 8–9 G. It is, however, very fatiguing. Positive pressure breathing combined with a G-suit which fully covers the lower limbs and abdomen will maintain performance at 9 G for many seconds.

Spitfire pilots and The Franks Mark II suits which were used by the United States Army Air Forces and Royal Canadian Air Force pilots. U.S. pilots tested them during 1944, but found the water system uncomfortable and were issued an air-inflatable design known as Berger suits from September 1944.

Conclusions

By now we have a basic knowledge about the Human Factors study history and its relevance in aviation, especially when it comes to safety. We know what our limits are and we know what we are capable of in extreme conditions and how to hone these skills through practice or training or to use equipment that help us nullify these barriers that we, as human beings, are imposed by nature. This information is crucial for people who intend to push themselves to the limit or for better managing the human resources side of aviation (or even any other domain) when workload may be too much for some people.

An alternative approach to shift organization and management in air traffic control was presented in this thesis. This different systematization of controllers’ timetables has its main focus of increasing the quality and efficiency of work by rearranging individuals’ schedules such that the most demanding time of the day meets the most stress tolerant people on the job. This is not, by any means, intended to discriminate employees in terms of performance levels; these evaluations and rearrangements are strictly made to create a comfortable workspace depending on the amount of stress tolerance level each individual has, stress tolerance being a criteria that cannot be easily modified, being a native trait. We have to accept that some people tire faster than others and create a workspace that best fits their limits, rather than limit their work or even replace them.

Some general information was also presented at the beginning, but also at the end about the G forces and the stresses it imposes on the body. This particular limitation is especially important to understand because it is exclusively met when we discuss about fighter jet pilots or astronauts and it seldom leads to fatality if treaded lightly. G-Suits were invented to overcome this effects, but it still poses a threat as aircraft still are capable of attaining speeds which in turn generate G forces higher that the maximum tolerance level (even with suits).

On a final note, although this thesis is aviation oriented, the information found in this paper can be as easily applied to any workspace or even used for personal evolution. The source code for the program can be easily adapted to the required workspace, by taking into account its respective workload in a working day and the evaluation model added at the end of this paperwork can be a reference as to how evaluations should look, as long as difficulty level is reduced or increased, again depending on the workspace.

References

Chapter I:

https://www.youtube.com/watch?v=5r1aFRiqLCI – History of Human Factors

https://www.hfes.org//Web/Default.aspx – Human Factors and Ergonomics Society

https://books.google.ro/books?hl=ro&lr=&id=WxJVNLzvRVUC&oi=fnd&pg=PA3&dq=aviation+ergonomics&ots=pXqqERWupc&sig=dL7jTkMibS-dujTqNZ5Jb_sJ96E&redir_esc=y#v=onepage&q=aviation%20ergonomics&f=false – Handbook of Human Factors and Ergonomics

https://books.google.ro/books?hl=ro&lr=&id=_wxu1hug3k4C&oi=fnd&pg=PP9&dq=The+Medical+Research+Council+(MRC)+sponsored+the+Climate+and+Working+Efficiency+Research+Unit+in+Oxford+and+the+Applied+Psychology+Research+Unit+in+Cambridge&ots=cc7Ktl9-0v&sig=zkxU112cNx_ekc2Zp83DJeIV9vg&redir_esc=y#v=onepage&q=The%20Medical%20Research%20Council%20(MRC)%20sponsored%20the%20Climate%20and%20Working%20Efficiency%20Research%20Unit%20in%20Oxford%20and%20the%20Applied%20Psychology%20Research%20Unit%20in%20Cambridge&f=false – Biological Ergonomics

https://drive.google.com/folderview?id=0Bz1QRitqv5QERmVrd2tLRWdVQUE&usp=sharing –

Professor Silviu Zancu’s materials regarding Human Factors (also used in Chapters II – IV)

http://www.dtic.mil/dtic/tr/fulltext/u2/a116394.pdf – Human Factors in Air Traffic Control

Chapter II:

https://www.youtube.com/watch?v=_SSGJGHtMuY – Human Performance and its Limitations

http://www.livescience.com/34128-limits-human-survival.html – The Limits of Human Survival

http://www.popsci.com/science/article/2011-04/future-travel – Exploring the Human Limits

Chapter III:

Discovery’s “Human Body – Pushing the Limits” Documentary Series

Chapter IV:

https://explorable.com/how-does-stress-affect-performance -How does Stress Affect Performance

https://en.wikipedia.org/wiki/Stress_in_the_aviation_industry – Stress in Aviation Industry

http://aviationknowledge.wikidot.com/aviation:stress-in-aviation – Stress in Aviation

http://www.tutorialspoint.com/java/ – Java Tutorials

https://docs.oracle.com/javase/tutorial/ – Java Tutorials

https://www.youtube.com/watch?v=3u1fu6f8Hto – Java Tutorials

http://www.indiabix.com/online-test/logical-reasoning-test/ – Logical Reasoning Test

AS LROPTMA Flight List at 01-05:43 >> / ATFCM (issued by Eurocontrol)

AD LRBS Flight List at 01-05:44 >> / ATFCM (issued by Eurocontrol)

AD LROP Flight List at 01-05:43 >> / ATFCM (issued by Eurocontrol)

Chapter V:

http://9gag.com/gag/aBYDyLz – The G-Force Effect on Pilots

https://en.wikipedia.org/wiki/G-suit – The G-Suit

http://www.defence.gov.au/news/raafnews/editions/4616/features/feature02.htm – G-Suit Features

http://www.encyclopedia.com/doc/1O128-GandGsuit.html – G and G-Suit

Annexes

Annex I: Otopeni and Băneasa Terminal Manoeuvring Area Flight List at 1st of June 2016 / ATFCM

Annex II: Evaluation model for determining stress tolerance levels for Air Traffic Controllers

Question 1

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 2

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 3

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 4

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 5

Question 6

The bottom boxes create a rule that has to be applied in the box directly above them. Select which of options A to F correspond to the rule below the box with the question mark.

Question 7

The bottom boxes create a rule that has to be applied in the box directly above them. Select which of options A to F correspond to the rule below the box with the question mark.

Question 8

Question 9

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 10

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 11

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 12

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 13

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 14

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 15

The boxes run in a sequence from left to right. You must determine which box (from options A to F) goes in the missing part of the sequence.

Question 16

Question 17

Question 18

Question 19

Question 20

Annex III: Java code for “Creating a dynamic workspace based on stress tolerance levels”

Controller.java – Source

package com.mycompany.emi2;

import java.util.LinkedList;

public class Controller {

public static void main(String[] args) {

LinkedList<Person> persons = new LinkedList<>();

java.awt.EventQueue.invokeLater(new Runnable() {

public void run() {

new MainFrame(persons).setVisible(true);

}

});

}

}

Input.java – Source

package com.mycompany.emi2;

import java.util.LinkedList;

public class Input extends javax.swing.JFrame {

private LinkedList<Person> persons;

private MainFrame main;

/**

* Creates new form Input

*/

public Input(LinkedList<Person> persons, MainFrame main) {

initComponents();

this.persons = persons;

this.main = main;

}

/**

* This method is called from within the constructor to initialize the form.

* WARNING: Do NOT modify this code. The content of this method is always

* regenerated by the Form Editor.

*/

@SuppressWarnings("unchecked")

Generated Code // Will not be included because it is automatically generated

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {

String name = nume.getText();

String surname = prenume.getText();

int scor = Integer.parseInt(score.getText());

Person p = new Person(name, surname, scor);

persons.add(p);

this.dispose();

main.increment();

}

private void cancelActionPerformed(java.awt.event.ActionEvent evt) {

this.dispose();

}

// Variables declaration – do not modify

private javax.swing.JButton cancel;

private javax.swing.JButton jButton1;

private javax.swing.JLabel jLabel1;

private javax.swing.JLabel jLabel2;

private javax.swing.JLabel jLabel3;

private javax.swing.JTextField nume;

private javax.swing.JTextField prenume;

private javax.swing.JTextField score;

// End of variables declaration

}

Table.java – Source

package com.mycompany.emi2;

import java.util.Comparator;

import java.util.Iterator;

import java.util.LinkedList;

import javax.swing.table.DefaultTableModel;

import javax.swing.table.TableModel;

public class Table extends javax.swing.JFrame {

private DefaultTableModel defaultModel;

private LinkedList<Person> persons;

private LinkedList<Person> tura1;

private LinkedList<Person> tura2;

private LinkedList<Person> tura3;

public Table(LinkedList<Person> persons) {

initComponents();

defaultModel = (DefaultTableModel) jTable1.getModel();

this.persons = persons;

tura1 = new LinkedList<>();

tura2 = new LinkedList<>();

tura3 = new LinkedList<>();

persons.sort(new Comparator<Person>() {

@Override

public int compare(Person o1, Person o2) {

if (o1.getScore() > o2.getScore()) {

return -1;

} else if (o1.getScore() < o2.getScore()) {

return 1;

}

return 0;

}

});

int contortura = 0;

for (int i = 0; i < persons.size() / 2; i++) {

if (contortura < 3) {

System.out.println(persons.get(i));

tura1.addLast(persons.get(i));

tura1.addLast(persons.get(persons.size() – 1 – i));

} else if (3 <= contortura && contortura < 6) {

tura2.addLast(persons.get(i));

tura2.addLast(persons.get(persons.size() – 1 – i));

} else if (6 <= contortura && contortura < 9) {

tura3.addLast(persons.get(i));

tura3.addLast(persons.get(persons.size() – 1 – i));

}

contortura++;

}

setTura(tura1,true);

setTura(tura2,false);

setTura(tura3,true);

setTura(tura1,false);

setTura(tura2,true);

setTura(tura3,false);

setTura(tura1,true);

setTura(tura2,false);

}

public void setTura(LinkedList<Person> tura, boolean a) {

if (a) {

Iterator it = tura.iterator();

int counter = 0;

while (it.hasNext()) {

Person p = (Person) it.next();

String words[] = new String[4];

if (counter%2==0) {

words[0] = p.getName();

words[1] = p.getSurname();

words[2] = "9-20";

words[3] = "D";

} else {

words[0] = p.getName();

words[1] = p.getSurname();

words[2] = "9-21";

words[3] = "D";

}

counter++;

defaultModel.addRow(words);

}

} else {

Iterator it = tura.iterator();

int counter = 0;

while (it.hasNext()) {

Person p = (Person) it.next();

String words[] = new String[4];

if (counter%2==0) {

words[0] = p.getName();

words[1] = p.getSurname();

words[2] = "21-9";

words[3] = "N";

} else {

words[0] = p.getName();

words[1] = p.getSurname();

words[2] = "20-9";

words[3] = "N";

}

counter++;

defaultModel.addRow(words);

}

}

}

/**

* This method is called from within the constructor to initialize the form.

* WARNING: Do NOT modify this code. The content of this method is always

* regenerated by the Form Editor.

*/

@SuppressWarnings("unchecked")

Generated Code // Will not be included because it is automatically generated

private void detailsActionPerformed(java.awt.event.ActionEvent evt) {

java.awt.EventQueue.invokeLater(new Runnable() {

public void run() {

new DetailedTable(jTable1.getSelectedRow()).setVisible(true);

}

});

}

private void RedoActionPerformed(java.awt.event.ActionEvent evt) {

this.dispose();

persons.clear();

}

// Variables declaration – do not modify

private javax.swing.JButton Redo;

private javax.swing.JButton details;

private javax.swing.JScrollPane jScrollPane1;

private javax.swing.JTable jTable1;

// End of variables declaration

}

DetailedTable.java – Source

package com.mycompany.emi2;

import javax.swing.table.DefaultTableModel;

public class DetailedTable extends javax.swing.JFrame {

/**

* Creates new form DetailedTable

*/

private DefaultTableModel defaultModel;

public DetailedTable(int number) {

initComponents();

defaultModel = (DefaultTableModel) jTable1.getModel();

if(number>=0 && number<6){

}

else if(number>=6 && number<12){

}

else if(number>=12 && number<18){

}

else if(number>=18 && number<24){

}

else if(number>=24 && number<30){

}

else if(number>=30 && number<36){

}

else if(number>=36 && number<42){

}

else if(number>=42 && number<48){

}

}

/**

* This method is called from within the constructor to initialize the form.

* WARNING: Do NOT modify this code. The content of this method is always

* regenerated by the Form Editor.

*/

@SuppressWarnings("unchecked")

Generated Code // Will not be included because it is automatically generated

private void closeActionPerformed(java.awt.event.ActionEvent evt) {

this.dispose();

}

// Variables declaration – do not modify

private javax.swing.JButton close;

private javax.swing.JScrollPane jScrollPane1;

private javax.swing.JTable jTable1;

// End of variables declaration

}

For best results use NetBeans IDE 8.1 when running the code, as it completes the missing components mentioned throughout the program.