Aviation Decision-Making Processes

Human Factors in Aviation

• Human factors (HF) encompass many technical aspects of flying.
• HF includes the interaction of humans, the environment, and machinery.
• Humans are terrestrial creatures, but how can we adapt to flying?
• Many WWII aviation accidents stemmed from pilot incapacitation (not combat).
• Many accidents are preventable.
• 85% of accidents result from human factors issues.
• Examples include disorientation, incapacitation, illusions, and death.
• HF considerations involve human capabilities and limitations within the aviation environment.

Aviation Medicine - Medical Requirements

• Medical Certificate (MC) requirements exist (404.03).
• Issuance, renewal, and validity of the MC are crucial (404.04).
• Exercise of privileges is subject to restrictions and regulations (404.06).

General Health

• Pilots need to be free of conditions that affect alertness, decision making, and reaction time.
• Certain medical conditions may prevent someone from obtaining a medical certificate.
• Acute infections can temporarily disqualify a pilot.
• Issues like colds, nausea, fatigue, indigestion, and stress are also considered.

Physical Factors

• Discussion about physical factors in flight, encompassing aspects of workload and pilot capability.

The Atmosphere

• The atmosphere is composed of:
  • Oxygen: 21%
  • Nitrogen: 78%
  • Other gases: 1%
• Standard atmospheric pressure is 1013.2mb.
• Oxygen partial pressure at 1000mb is 210mb (or 760mm/29.92"Hg). -Important to note that these figures vary with altitude

Atmospheric Effects

• Decreased atmospheric pressure leads to hypoxia.
• Decreased partial pressure also causes hypoxia.
• Trapped gases (abdominal, sinus, dental pains) can arise due to changes in pressure.
• Evolved gases lead to decompression sickness.

Hypoxia

• Caused by inadequate oxygen in body tissues.
• Modern technology allows operation at high altitudes.
• Hypoxia is one of the most insidious physiological problems.
• Hypoxia is difficult to detect in oneself.
• Lack of sufficient oxygen in body cells and tissues.
• Increased altitude decreases the partial pressure of oxygen.
• Greatest concentration of air molecules is at the Earth's surface, diminishing with altitude.
• At 15,000 feet, oxygen is half that of sea level.
• Detecting Hypoxia in oneself is difficult; early stages may feel like well-being
• Brain center warning of hypoxia may be affected first.
• Symptoms may include euphoria, reduced vision, poor judgement, slow reaction time, LOC and death.

Types of Hypoxia

• Hypoxic hypoxia
• Histotoxic hypoxia
• Anemic hypoxia
• Stagnant hypoxia

Hypoxic Hypoxia

• Normal effect of altitude.
• Lack of oxygen in tissue due to low partial pressure of oxygen at altitude.
• Reduced oxygen in the lungs.

Atmosphere Composition and Properties

• The atmosphere has weight.
• 14.7psi at sea level - 1013.2mb
• Half of the atmosphere is below 18,000 feet.
• 1/4 of the atmosphere is at 34,000 feet.

Oxygen Dissociation Curve with Hemoglobin

• Relationship between % saturation of blood with oxygen and altitude.
• Important to recognise hypoxic range as unsafe.

Time of Useful Consciousness

• Time of useful consciousness at various altitudes.
• Time decreases with increasing altitude.
• Shortened time is critical factor in aviation.

Hypoxic Hypoxia (Specific Altitudes)

• Detailed effects at different altitudes, from normal to incapacitation. Includes descriptions of physiological effects at altitudes and symptoms, up to incapacitation and LOC.

Histotoxic Hypoxia

• Chemical poisoning (e.g., carbon monoxide) and high blood alcohol content.
• Also high blood alcohol content
• Insufficient oxygen absorption by tissues.
• Any alcohol/drugs are prohibited.
• Specific regulations/ restrictions for time of consumption before flying, to minimize and mitigate effects of drugs/ alcohol.

Anemic Hypoxia

• Oxygen transport by hemoglobin is affected.
• Carbon monoxide is dangerous, binding with hemoglobin 210 times more strongly than oxygen; this reduces blood oxygen carrying capacity.
• Lack of oxygen carrying capacity.
• CO is colorless, odorless, and tasteless.
• Sources of CO include fuel combustion, defects in the aircraft, and electrical fires.
• Symptoms, diagnosis and procedures for CO poisoning.
• Precautions to take if concerned about CO

Carbon Monoxide Poisoning

• Symptoms may include sluggishness, headache, vision issues.
• Can lead to vomiting, convulsions, coma and ultimately death.
• Smoking significantly lowers altitude tolerance.
• Symptoms, diagnosis and procedures for CO poisoning.
• Precautions to take if concerned about CO

Procedure to Counteract CO Poisoning

• Shut off heat.
• Open fresh air sources.
• Avoid smoking.
• Administer 100% oxygen.
• Prompt medical treatment is crucial.

Stagnant Hypoxia

• Brain is deprived of adequate blood supply (e.g., high G-forces).
• First symptoms (Grey-Out) reduced vision and peripheral vision.
• Increased G-forces may cause loss of consciousness (G-LOC).
• Increased blood pressure during an associated Red-Out event.

Hypoxia - Effects on Vision

• Retina is more dependent on oxygen than other body parts.
• Evidence of hypoxia can occur at 5000 feet at night.
• Reduced night vision is a possible result.

Hypoxia - At 10,000 Feet

• Altitude at which pilots typically begin to experience hypoxia onset.
• Factors like age, fitness, and drug use can influence susceptibility.

Hypoxia - At 14,000 Feet

• Symptoms of hypoxia at this altitude include lassitude, indifference, dimmed vision, hand tremors, and a clouding of thought/errors in judgment.
• Cyanosis (blue discolouring of fingernails) is a noticeable sign.

Hypoxia - At 16,000 Feet

• Possible pilot behavior like belligerence or euphoria.
• Disorientation is a significant risk.
• Loss of control is possible.

Hypoxia - At 18,000 Feet

• Primary shock becomes evident.
• Loss of consciousness is a potential outcome.

Hypoxia - At High Altitudes

• Prolonged periods of reduced oxygen can lead to death.
• Use supplemental oxygen at altitudes above 10,000 feet during the day (refer to specific altitude restrictions as legally required)
• 5,000 feet at night.

Hypoxia Recovery

• Prevent onset by using supplementary oxygen when required for various altitudes.
• Maintain adequate fitness levels regularly, including physical and mental fitness.
• Be aware of early symptoms; good pilots will be familiar with these symptoms; this includes frequent practice to help identify and recognize symptoms -Early symptoms, including the physiological effects, that commonly occur during high-altitude flight situations

Hyperventilation

• Overbreathing, usually stemming from anxiety or tension.
• Symptoms: dizziness, tingling of fingers/toes, hot/cold sensations, nausea, etc. and associated symptoms.
• Symptoms similar to hypoxia (but caused by rapid breathing). Also includes detailed recommendations on recovery and potential associated factors.

Decompression Sickness

• Trapped gases in the body can expand and contract, leading to pain and possible incapacitation; detailed explanation of the physiological process involved.

Ears

• Inner ear equilibrium/cochlea, Eustachian tube equalization/issues during descent/ascent/sinus infections, and the Valsalva technique are important aspects. Also includes detailed explanations of the anatomical and physiological considerations.

Semicircular Canals - Vestibular Illusions

• Associated with equilibrium.
• Fluid filled, tiny hairs relate motion to the brain.
• Accelerated turns (contact velocity) and sensations
• Brain receives incorrect signals; can result in movement in the opposite direction. -Detailed discussion on the impact of turns on the Vestibular system.

Sinus, Teeth, Gastrointestinal Gases

• Pressure equalization issues (common cold, toothache, inflated cavities, abscesses etc).
• Gases in digestive system can cause pain/discomfort.
• Symptoms of these can worsen with altitude.
• Specific anatomical considerations for understanding the issues involved

Evolved Gases

• Nitrogen bubbles in body; dangerous, causes decreased barometric pressure.
• Can lead to circulation issues, joint pain, tissue damage. -Detailed discussion on the causes and effects of evolved gases and specific physiological effects. -Detailed discussion on the physiological effects.
• Recommendations on the conditions to prevent these dangers/ effects from occurring

Scuba Diving

• Risk of decompression sickness, but at lower altitudes than expected.
• Body supersaturates with nitrogen. -Detailed explanations on the physiological effects of scuba dives, and associated dangers of flying -Detailed discussion on the recommendations to prevent decompression sickness or its risk of occurrence
• Detailed explanation of conditions to avoid flight after dives

Vision

• Exposure to higher light levels while flying.
• Atmosphere less dense/lots of reflections.
• Should wear sunglasses to protect eyes from harmful wavelengths. Includes recommendations for visual safety.

Night Vision

• Cones and Rods in eyes; Detailed description of the specific roles of cones and rods in vision function.
• Need for proper adaptation; explanation of the processes involved in adjusting to light changes.
• Red light is recommended.
• Understand that visual issues can be a symptom of hypoxia; a detailed discussion emphasizing the connection between visual impairments and hypoxia's effect on vision function.

Rain on the Windshield

• Rain on the windshield in poor weather can affect your perception and lead to potential errors in judgement. Also includes specific recommendations for coping with these situations

Haze on Final Approach

• Haze on final approach can change your visual perception of the runway, potentially leading to errors and a higher approach. Detailed discussion and recommendations for dealing with these effects

Sloped Runway

• Sloped runways create illusions concerning altitude with tendency to fly approach too high or low, detailed explanation with recommendations on how to deal with the phenomenon.

Runway Width

• Narrower runways create illusion of flying higher than you are; wider runways create the illusion of flying lower. Flight paths tend to be affected. Detailed discussion and recommendations for dealing with these effects

Surrounding Terrain

• Surrounding terrain (high or low) can affect your perception of height to the runway. Detailed discussion with recommendations for dealing with these effects

Turning Illusions

• Downwind to into-wind changes in airflow can create deceptive sensations; Detailed discussion with recommendations for dealing with these effects.

Empty Field Myopia

• Eyes respond to lack of stimulus; focus too close and objects appear smaller.
• Adjust vision by focusing on wing tips; a clear discussion of how to mitigate the issue to remain safe.

Sensory Illusions

• General discussion of sensory and perceptual illusions, and how they can affect a pilot's ability to judge position and circumstances; Importance and causes of sensory illusions.

Spatial Disorientation

• Loss of bearing/confusion relative to the surface; Causes of spatial disorientation, including reduced vision, flickering shadows, and their combined effects in causing vertigo, and more.

Coriolis Effect

• Movement in semicircular canals during turns can affect perception resulting in disorientation or balance issues; details on causes and mitigation strategies, along with recommendations to mitigate risks

Somatogravic - False Climb Illusion

• Body senses changes in pitch, acceleration, etc. and it may misinterpret the signals causing a false climb scenario; Detailed and comprehensive explanation on the mechanisms associated.

Black Hole Illusion

• Darkness without visual cues can cause overestimation of altitude, and lead to landing issues/short of runway; explanation on how to mitigate these risks.

Autokinesis

• Stationary light in featureless sky can appear to move; details on how this illusion affects the pilot, including factors that can cause similar perceptual issues
• Minute involuntary eye motions/can result in vertigo; discussion on how this issue can be mitigated

False Horizon

• Difficulty distinguishing horizon on clear, moonless nights; Lights/stars below the horizon can blend with the real horizon. Also includes tips and tricks on how to avoid these issues

Alcohol & Drugs

• Alcohol: Minimum 12-hour period from consumption/use before flying, to minimize effects with altitude.
• Drugs: Some medications aren't permitted. Must verify with a licensed flight surgeon, as specific requirements vary
• Explains the why of the requirements associated with drinking and recreational drugs in aviation

Blood Donation

• Recommendations on avoiding blood donation close to flying situations: explanation of why there are restrictions

Anesthesia

• Information on the appropriate recovery period after general and local anesthesia, before returning to flight; Importance and details on recovery.

Other Considerations

• Factors to consider/ check for flying safely (stress, fatigue, pregnancy, eating, etc.); detailed discussion on the role of factors, including recommendations for how to mitigate these situations

Other Irritants

• Noise, vibration, and temperature can interfere with concentration and safety in flight; Details on causes and recommended solutions.

I.M.S.A.F.E. Checklist

• Helpful checklist to ensure safety in flight and contains critical safety considerations
• Critical considerations for pilots to utilize for safety pre-flight.

Hazardous Attitudes

• Anti-Authority; tendency to resist authority figures and rules.
• Resignation: Feeling that effort is futile.
• Impulsivity: Acting promptly without due consideration.
• Invulnerability/Macho: Believing you are exempt from risks.

Avoiding Hazardous Attitudes (The How-To)

• Recommendations for recognizing/avoiding hazardous attitudes; detailed explanation on how to mitigate these risks and considerations

Decision-Making Process

• Structured method, or process to assure decisions are good ones; Detailed explanation on the steps associated and how to use the process

Workload Management

• Managing workload to avoid exceeding capacity, by utilizing margins of safety; detailed discussion on the role of safety margins
• Understanding and being aware of pilot capacity levels is key.
• Detailed explanation including associated recommendations for how to deal effectively with workload.

Crew Resource Management (CRM)

• Important in multi-crew aircraft operation; detailed explanations on the importance of teamwork, cooperation, and communication in aircrew coordination and its effects.
• Cooperation, communication, and effectively using resources.
• Importance of resource management for safety.
• Examples of how to use CRM in different scenarios.

Personal Minimums

• Setting personal minimums/adjusting them as needed, to be used for safety during various flight situations; importance of understanding personal limitations to improve accuracy
• Examples of minimum requirements to consider for safe flight.

The End... Almost

• Knowledge, instruments, and being aware of personal limitations are critical to being a safe pilot.
• Emphasis on the vital importance of knowledge in safety.