- •Textbook Series
- •Contents
- •1 Basic Concepts
- •The History of Human Performance
- •The Relevance of Human Performance in Aviation
- •ICAO Requirement for the Study of Human Factors
- •The Pilot and Pilot Training
- •Aircraft Accident Statistics
- •Flight Safety
- •The Most Significant Flight Safety Equipment
- •Safety Culture
- •Reason’s Swiss Cheese Model
- •The Five Elements of Safety Culture
- •Flight Safety/Threat and Error Management
- •Threats
- •Errors
- •Undesired Aircraft States
- •Duties of Flight Crew
- •2 The Circulation System
- •Blood Circulation
- •The Blood
- •Composition of the Blood
- •Carriage of Carbon Dioxide
- •The Circulation System
- •What Can Go Wrong
- •System Failures
- •Factors Predisposing to Heart Attack
- •Insufficient Oxygen Carried
- •Carbon Monoxide
- •Smoking
- •Blood Pressure
- •Pressoreceptors and their Function Maintaining Blood Pressure
- •Function
- •Donating Blood and Aircrew
- •Pulmonary Embolism
- •Questions
- •Answers
- •3 Oxygen and Respiration
- •Oxygen Intake
- •Thresholds of Oxygen Requirements Summary
- •Hypoxic Hypoxia
- •Hypoxic Hypoxia Symptoms
- •Stages/Zones of Hypoxia
- •Factors Determining the Severity of and the Susceptibility to Hypoxic Hypoxia
- •Anaemic Hypoxia
- •Time of Useful Consciousness (TUC)
- •Times of Useful Consciousness at Various Altitudes
- •Effective Performance Time (EPT)
- •Hyperventilation
- •Symptoms of Hyperventilation
- •Hypoxia or Hyperventilation?
- •Cabin Pressurization
- •Cabin Decompression
- •Decompression Sickness (DCS)
- •DCS in Flight and Treatment
- •Questions
- •Answers
- •4 The Nervous System, Ear, Hearing and Balance
- •Introduction
- •The Nervous System
- •The Sense Organs
- •Audible Range of the Human Ear and Measurement of Sound
- •Hearing Impairment
- •The Ear and Balance
- •Problems of Balance and Disorientation
- •Somatogyral and Somatogravic Illusions
- •Alcohol and Flying
- •Motion Sickness
- •Coping with Motion Sickness
- •Questions
- •Answers
- •5 The Eye and Vision
- •Function and Structure
- •The Cornea
- •The Iris and Pupil
- •The Lens
- •The Retina
- •The Fovea and Visual Acuity
- •Light and Dark Adaptation
- •Night Vision
- •The Blind Spot
- •Stereopsis (Stereoscopic Vision)
- •Empty Visual Field Myopia
- •High Light Levels
- •Sunglasses
- •Eye Movement
- •Visual Defects
- •Use of Contact Lenses
- •Colour Vision
- •Colour Blindness
- •Vision and Speed
- •Monocular and Binocular Vision
- •Questions
- •Answers
- •6 Flying and Health
- •Flying and Health
- •Acceleration
- •G-forces
- •Effects of Positive G-force on the Human Body
- •Long Duration Negative G
- •Short Duration G-forces
- •Susceptibility and Tolerance to G-forces
- •Summary of G Tolerances
- •Barotrauma
- •Toxic Hazards
- •Body Mass Index (BMI)
- •Obesity
- •Losing Weight
- •Exercise
- •Nutrition and Food Hygiene
- •Fits
- •Faints
- •Alcohol and Alcoholism
- •Alcohol and Flying
- •Drugs and Flying
- •Psychiatric Illnesses
- •Diseases Spread by Animals and Insects
- •Sexually Transmitted Diseases
- •Personal Hygiene
- •Stroboscopic Effect
- •Radiation
- •Common Ailments and Fitness to Fly
- •Drugs and Self-medication
- •Anaesthetics and Analgesics
- •Symptoms in the Air
- •Questions
- •Answers
- •7 Stress
- •An Introduction to Stress
- •The Stress Model
- •Arousal and Performance
- •Stress Reaction and the General Adaption Syndrome (GAS)
- •Stress Factors (Stressors)
- •Physiological Stress Factors
- •External Physiological Factors
- •Internal Physiological Factors
- •Cognitive Stress Factors/Stressors
- •Non-professional Personal Factors/Stressors
- •Stress Table
- •Imaginary Stress (Anxiety)
- •Organizational Stress
- •Stress Effects
- •Coping with Stress
- •Coping with Stress on the Flight Deck
- •Stress Management Away from the Flight Deck
- •Stress Summary
- •Questions
- •Answers
- •Introduction
- •Basic Information Processing
- •Stimuli
- •Receptors and Sensory Memories/Stores
- •Attention
- •Perception
- •Perceived Mental Models
- •Three Dimensional Models
- •Short-term Memory (Working Memory)
- •Long-term Memory
- •Central Decision Maker and Response Selection
- •Motor Programmes (Skills)
- •Human Reliability, Errors and Their Generation
- •The Learning Process
- •Mental Schema
- •Questions
- •Answers
- •9 Behaviour and Motivation
- •An Introduction to Behaviour
- •Categories of Behaviour
- •Evaluating Data
- •Situational Awareness
- •Motivation
- •Questions
- •Answers
- •10 Cognition in Aviation
- •Cognition in Aviation
- •Visual Illusions
- •An Illusion of Movement
- •Other Sources of Illusions
- •Illusions When Taxiing
- •Illusions on Take-off
- •Illusions in the Cruise
- •Approach and Landing
- •Initial Judgement of Appropriate Glideslope
- •Maintenance of the Glideslope
- •Ground Proximity Judgements
- •Protective Measures against Illusions
- •Collision and the Retinal Image
- •Human Performance Cognition in Aviation
- •Special Situations
- •Spatial Orientation in Flight and the “Seat-of-the-pants”
- •Oculogravic and Oculogyral Illusions
- •Questions
- •Answers
- •11 Sleep and Fatigue
- •General
- •Biological Rhythms and Clocks
- •Body Temperature
- •Time of Day and Performance
- •Credit/Debit Systems
- •Measurement and Phases of Sleep
- •Age and Sleep
- •Naps and Microsleeps
- •Shift Work
- •Time Zone Crossing
- •Sleep Planning
- •Sleep Hygiene
- •Sleep and Alcohol
- •Sleep Disorders
- •Drugs and Sleep Management
- •Fatigue
- •Vigilance and Hypovigilance
- •Questions
- •Answers
- •12 Individual Differences and Interpersonal Relationships
- •Introduction
- •Personality
- •Interactive Style
- •The Individual’s Contribution within a Group
- •Cohesion
- •Group Decision Making
- •Improving Group Decision Making
- •Leadership
- •The Authority Gradient and Leadership Styles
- •Interacting with Other Agencies
- •Questions
- •Answers
- •13 Communication and Cooperation
- •Introduction
- •A Simple Communications Model
- •Types of Questions
- •Communications Concepts
- •Good Communications
- •Personal Communications
- •Cockpit Communications
- •Professional Languages
- •Metacommunications
- •Briefings
- •Communications to Achieve Coordination
- •Synchronization
- •Synergy in Joint Actions
- •Barriers to Crew Cooperation and Teamwork
- •Good Team Work
- •Summary
- •Miscommunication
- •Questions
- •Answers
- •14 Man and Machine
- •Introduction
- •The Conceptual Model
- •Software
- •Hardware and Automation
- •Intelligent Flight Decks
- •Colour Displays
- •System Active and Latent Failures/Errors
- •System Tolerance
- •Design-induced Errors
- •Questions
- •Answers
- •15 Decision Making and Risk
- •Introduction
- •The Mechanics of Decision Making
- •Standard Operating Procedures
- •Errors, Sources and Limits in the Decision-making Process
- •Personality Traits and Effective Crew Decision Making
- •Judgement Concept
- •Commitment
- •Questions
- •Answers
- •16 Human Factors Incident Reporting
- •Incident Reporting
- •Aeronautical Information Circulars
- •Staines Trident Accident 1972
- •17 Introduction to Crew Resource Management
- •Introduction
- •Communication
- •Hearing Versus Listening
- •Question Types
- •Methods of Communication
- •Communication Styles
- •Overload
- •Situational Awareness and Mental Models
- •Decision Making
- •Personality
- •Where We Focus Our Attention
- •How We Acquire Information
- •How We Make Decisions
- •How People Live
- •Behaviour
- •Modes of Behaviour
- •Team Skill
- •18 Specimen Questions
- •Answers to Specimen Papers
- •Revision Questions
- •Answers to Revision Questions
- •Specimen Examination Paper
- •Answers to Specimen Examination Paper
- •Explanations to Specimen Examination Paper
- •19 Glossary
- •Glossary of Terms
- •20 Index
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Health and Flying 6
Caffeine is a diuretic and can increase the risk of dehydration, particularly when relative humidity is low. Caffeine is found in the blood only 10 minutes after ingestion and has a halflife of approximately 4 hours.
Regular intakes of caffeine over a long period can lead to:
•Ulcers and other digestive disorders.
•Increased risk of cardiac arrest.
•Hypertension.
•Personality disorders.
•Chronic muscle tension.
•Insomnia.
•Disorientation.
•Hyperactiveness (especially in children).
The withdrawal symptoms (normally 12 - 16 hours after last dose) are:
•Irritability.
•Sluggishness.
•Headaches.
•Depression.
•Drowsiness.
•Lethargy.
•Occasional nausea and vomiting (in the more serious case).
The approximate contents of caffeine sources are shown below:
|
Caffeine content (mg) |
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|
|
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Cup of brewed coffee |
80 - 135 |
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Cup of instant coffee |
65 - 100 |
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Cup of decaffeinated coffee |
3 |
- 4 |
|
|
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Cup of espresso coffee |
100 |
|
|
|
|
Cup of black tea |
30 |
- 70 |
|
|
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Average 12 oz can of Cola |
30 |
- 60 |
|
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Bar of dark chocolate |
30 |
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Average cold relief tablet |
30 |
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Can of 7Up |
|
0 |
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It is recommended that the absolute maximum caffeine limit of approximately 250 - 300 mg (2 - 3 cups of coffee) a day should be rigorously respected by aircrew.
Psychiatric Illnesses
Serious forms of psychiatric illness associated with loss of insight or contact with reality - a psychosis such as bipolar disorder (manic depression) or schizophrenia - will always result in the permanent loss of a flying licence.
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There are less serious mental states of the neurotic type - anxiety states, phobic states, depression, or obsessional disorders which are treatable by drugs or counselling. Whilst these disorders are active or under treatment they, too, will be a bar to flying.
After successful treatment, however, when in good health and off all drug treatment most pilots will be able to return to flying duties.
TropicalDiseasesandMedicalHazards(includingHepatitisandDiabetes)
Aircrew are responsible for arranging their own vaccinations against the communicable diseases. If travelling for the first time to areas where these may be found, a medical brief should be arranged prior to travel. Although the list below covers the most important medical hazards which may be encountered, it is far from complete.
Note: Approximately two thirds of the cabin air in modern airliners is recirculated which can in itself cause health problems such as Legionnaires disease and be associated with the spread of other infections/diseases.
Malaria
Malaria is still considered as one of the world’s biggest killers. It is responsible for the death of about 1 million infants and children every year in Africa.
The symptoms include recurrent cyclic fever, uncontrolled shivering and delirium and must be treated in hospital.
Over the years, too much reliance has been placed on antimalarial tablets which are providing less and less protection. The only sure way to stop catching malaria is to avoid being bitten by the mosquitoes which carry the protozoa responsible for the disease. The individual should wear long trousers and long sleeves in the evening, when the insects are active. When in air conditioned rooms, avoid opening the windows and always spray the room before retiring. If mosquito nets are provided - use them.
Should antimalarial prophylaxis be taken, the treatment should generally start a week before departure to an area where malaria is endemic and continue throughout the stay and for 4 weeks after leaving. Advice from an aviation medical specialist should be sought as to the choice of prophylactic drugs to be taken.
Tuberculosis
Tuberculosis (an airborne contagion) has made a dramatic return. This potentially fatal disease was virtually extinct in the developed world and was believed to be under control in other countries. However, in recent years there has been a great upsurge in the disease in many parts of Africa and other developing areas and it now compares with Malaria as a killer disease.
It is passed by airborne water droplets (normally through coughing or sneezing). The organism may lie dormant for several years before symptoms appear. These include a hacking cough, anorexia, chest pain, shortness of breath, fever and sweating. Hospitalization is necessary.
Smallpox
Smallpox is an acute viral infection. Although the World Health Organization confirmed in May 1980 that the disease had been eradicated, cases have reappeared.
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Health and Flying 6
Cholera
Cholera is contracted through food or water which has been contaminated by the faeces of infected persons. Outbreaks thus reflect poor sanitary and hygiene conditions.
Symptoms include vomiting, cramps and diarrhoea resulting in dangerous loss of body fluids. Liquid loss may be as much as 19 litres a day. Once fluids have been replaced, antibiotics may be given to stop the bacteria. A vaccine is available but is of questionable benefit.
Drinking only boiled or bottled water and eating only cooked food are the best preventative measures. It is noteworthy that aircrew should always check that the seal is intact before drinking from a bottle of water at hotels or restaurants. In many developing countries bottles are refilled and thus may contain contaminated water.
Yellow Fever
Yellow fever is an acute destructive disease usually found in tropical regions and is caused by a virus transmitted by infected mosquitos. The virus has an incubation period of 3 to 8 days. Symptoms include fever, liver damage (with accompanying jaundice) and intestinal disorders. Treatment consists of maintaining the blood volume and transfusions may be necessary. Vaccination confers immunity for 10 years.
Tetanus
Tetanus is an infection which is transmitted through spores via a puncture of the skin and attacks the central nervous system. The most characteristic symptom of tetanus is lockjaw. After the initial vaccination (3 over a 12 month period) revaccination every ten years is necessary.
Typhoid Fever
Typhoid is contacted through infected milk, water or food and affects the large intestine. Symptoms include high fever, headache, constipation which soon changes to diarrhoea and a rash which usually appears on the chest and abdomen. The disease is serious and can be fatal. The vaccine does not provide complete protection and a booster is required after two years.
Hepatitis
Hepatitis is a virus that affects the liver, causing its enlargement and can sometimes result in liver failure. Symptoms include fever, chills, headache, decreased appetite, tenderness in the upper right abdomen, dark urine, light-coloured faeces and yellow skin or eyes. Left untreated, the victim can fall into a coma and die. Of the six forms, the three most common are discussed briefly below.
Hepatitis A
Hepatitis A is primarily spread through food and water contamination. Undercooked or raw shellfish and seafood, along with raw vegetables are likely sources. Symptoms develop about one month after exposure to the virus.
It has been reported that Hepatitis A can also be transmitted through sexual contact and drug use (needle exchange).
Gamma globulin is used as a vaccine but can be of limited protection and short-lived.
Hepatitis B
Hepatitis B is more serious than Hepatitis A, resulting in chronic liver disease. It is spread through blood transfer rather than by eating. It is transmitted primarily via intravenous drug
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use (needle exchange), sexual contact and blood transfusion. Tattooing and immunisation with improperly sterilised syringes are also common causes. Vaccination is possible.
Hepatitis C
Hepatitis C is transmitted primarily through intravenous drug use and shared needles, maternal transmission and possibly some forms of sexual contact. Vaccines exist.
Diabetes
There are two types of Diabetes : types 1 and 2
Type 1
Often referred to as juvenile diabetes, this type is normally found in the young. Either there is a deficiency of insulin or a lack of production of insulin by the pancreas. People with type 1 diabetes therefore require regular insulin injections to manage their glucose/sugar levels.
Type 2
Usually effects adults and pilots are not immune to this condition. It is caused by either the pancreas not producing enough insulin to maintain a normal blood glucose level or, more usually, when the body is unable to effectively use the insulin (insulin resistant). Research is continuing to look more closely into how insulin resistance develops. It is thought that the principle causes of insulin resistance is obesity, poor diet and sedentary lifestyles.
Both types can be as a result of family history.
Symptoms
These include :
•Thirst
•Frequent urination
•Blurry vision
•Irritability
•Tingling or numbness in the hands or feet
•Frequent skin, bladder or gum infections
•Wounds that do not heal
•Extreme unexplained fatigue
In most cases of type 2 diabetes, there are no symptoms. In such cases, people can live for months, even years, without knowing they have the disease. This form of diabetes comes on so gradually that symptoms may not even be recognized.
Type 2 diabetes can potentially be avoided through diet and exercise and treatment includes diet modification and control, regular exercise, home blood glucose testing and, in some cases, oral medication and/or insulin injections
Complications
Complications may be numerous and include :
•Hypertension
•Tearing of the retina of the eyes which can lead to blindness
•Neuropathy (loss of feeling or numbness – especially of the lower limbs and feet)
•Blocked arteries with associated chances of heart attacks and strokes
•Kidney failure
•Hypoglycaemia caused by taking too much insulin and possible coma
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