Human Factors in Aviation

THE HUMAN FACTORS MODULE

MODULE OVERVIEW

  • Definition of Human Factors

    • Human Factors refers to people in their working and living environments.

    • Focus on their relationships with:

    • Equipment

    • Procedures

    • Environment

    • Other individuals.

    • Overall performance of humans within the aviation system.

  • Objectives of Human Factors

    • Optimize performance of individuals by systematically applying human sciences within the framework of system engineering.

    • Twin objectives:

    • Safety

    • Efficiency.

MISCONCEPTIONS ABOUT HUMAN FACTORS

  • What this module is NOT about:

    • It is not a guide to surpass personal human limitations or to gain unfair advantages over peers.

    • It does not provide numerical evidence to skip lectures or labs.

    • Does not intend to elicit negative feelings from students regarding the module.

IMPORTANCE OF HUMAN FACTORS IN AVIATION

  • Historical Context

    • Since the 1950s, human factors have contributed to approximately 73% of all aviation accidents.

    • Controlled Flight Into Terrain (CFIT) is the most prevalent incident type.

  • Common Causes of Human Factor Related Incidents

    • Loss of directional control.

    • Poor judgement and decision making.

    • Failure to maintain airspeed.

    • Poor flight planning.

    • Failure to maintain ground clearance.

  • Phases of Flight Prone to Accidents

    • Takeoff phase.

    • Descent up to final approach.

ORGANIZATIONAL CHALLENGES IN AVIATION

  • Financial Pressure on Safety

    • Commercial organizations may compromise flight safety due to financial constraints.

  • Indicators of Degraded Flight Safety

    • Stretched crew duty times.

    • Poor rostering practices.

    • Unserviceability of aircraft.

    • Weaknesses in maintenance and operational procedures.

    • Poor communication among crew members.

    • Non-standardization of cockpit layouts.

    • Absenteeism and poor industrial relations.

    • Rising accident rates.

SAFETY CULTURE IN AVIATION

  • Definition

    • Safety culture is the product of individual and group values, attitudes, perceptions, competencies, and behaviors that shape an organization's approach to health and safety.

  • Types of Safety Cultures

    • Open Culture: Involves all levels of personnel in safety discussions and information sharing.

    • Closed Culture: Reluctance to share safety information with external entities.

    • National Culture: Government and ethnic influences on safety perceptions.

  • Encouraging Factors for Good Safety Culture

    • Effective Leadership.

    • Strong Commitment to safety.

    • Positive role modeling.

ACCIDENTS AND INCIDENTS

  • Swiss Cheese Model of Accident Causation

    • Visual representation of organizational defenses; "cheese slices" represent barriers to accidents.

    • Each slice has holes indicating weaknesses; accidents occur when all holes align momentarily.

THREATS AND ERRORS

  • Definitions

    • Threats: Factors and conditions that can adversely affect performance (e.g., poor weather, equipment flaws).

    • Errors: Actions or inactions by flight crew that deviate from intended outcomes.

  • UNDesired Aircraft States

    • Latent Threats: Not immediately apparent, such as equipment design flaws or schedule pressures.

    • Environmental Threats: Include weather, terrain, and air traffic control challenges.

    • Procedural Errors: Issues with standard operating procedures (SOPs), checklist compliance.

    • Organizational Threats: Include operational pressure and maintenance issues.

    • Communication Errors: Miscommunications among crew members or external parties.

THREAT AND ERROR MANAGEMENT (TEM)

  • Three Components of TEM

    • Avoid

    • Trap

    • Mitigate

STUDYING HUMAN BIOLOGY

  • Read on Human Biology

    • Attendees are encouraged to read about human biology as it relates to external and internal factor impacts on bodily systems.

CIRCULATORY SYSTEM

  • Pulse Rate

    • Changes due to various factors (exercise, altitude, temperature).

  • Psychological Stimuli

    • Can trigger reactions in the circulatory system, such as:

    • Fight or Flight response.

    • Shock.

    • Emotional states like fear or anxiety.

  • Potential Issues

    • Circulatory system faults can result in insufficient oxygen delivery to the body.

OXYGEN AND RESPIRATION

  • Oxygen Transfer Mechanism

    • Oxygen enters the bloodstream via diffusion across capillaries surrounding alveoli during breathing.

    • Carbon Monoxide’s Impact:

    • Competes with oxygen for binding to red blood cells.

    • Results in oxygen deprivation and possible death.

  • Hypoxic Hypoxia: Shortage of oxygen is critical at high altitudes.

    • Symptoms include personality changes, impaired judgement, headaches, increase in breathing rates, visual impairments, among others.

  • Treatment for Hypoxia

    • Administer oxygen and descend below 10,000 feet where atmospheric conditions are sufficient.

  • Time of Useful Consciousness (TUC)

    • Duration a pilot has to recognize and respond to developing hypoxia. Influenced by individual fitness, workload, smoking, body weight, and decompression type.

DECOMPRESSION SICKNESS (DCS)

  • Caused by nitrogen bubbling in the blood due to pressure changes. May lead to:

    • Bends: Pain in joints due to nitrogen bubbles.

    • Creeps: Skin sensations from nitrogen.

    • Chokes: Blocked blood flow due to nitrogen.

    • Staggers: Brain blood flow obstruction.

    • Post Descent Collapse: Occurs up to 4 hours post-decompression.

NERVOUS SYSTEM AND BALANCE

  • Components of the Nervous System

    • Central Nervous System (CNS): Brain and spinal cord functions including sensory processing.

    • Peripheral Nervous System (PNS): Transmits information from body organs back to the CNS.

    • Autonomic Nervous System (ANS): Involuntary system controlling internal organ functions.

EAR, HEARING, AND BALANCE

  • Structure and Function of the Ear

    • Outer ear collects sound through the auditory canal.

    • Middle ear ossicles (Malleus, Incus, Stapes) transmit sound to the inner ear.

    • Inner ear contains cochlea, where sound vibration is translated into nerve impulses.

  • Balance Mechanisms

    • Semicircular canals and structures like ampulla detect head movements and contribute to balance perception.

EYE AND VISION

  • Anatomy of the Eye

    • Includes iris, pupil, lens, retina, optic nerve, and internal fluid compartments.

  • Vision Issues

    • Hyperopia: Distant objects focused accurately; close objects focused behind the retina due to a shorter-than-normal eyeball.

    • Myopia: Close objects focused correctly; distant objects focused in front of the retina due to a longer-than-normal eyeball.

FLYING AND HEALTH

  • G-Forces

    • Defined as acceleration referenced against gravitational pull, affecting body weight and blood pressure.

    • Long-term exposure can reduce blood flow to critical areas such as the brain leading to greying out or loss of consciousness (G-LOC).

  • Barotrauma: Pain from pressure differentials affecting air trapped in the body; includes conditions like otic barotrauma and sinus barotrauma.

ALCOHOL AND AVIATION

  • Metabolism of Alcohol

    • Body breaks down alcohol at a rate of 1 unit/hour (approximately 1 pint of beer).

    • Consuming food does not increase the rate of alcohol elimination.

    • Effects from alcohol, even in low doses, include impaired judgement, coordination, and increased susceptibility to hypoxia.

  • Aviation Alcohol Limits

    • Legal limits vary; many countries implement a zero-tolerance policy on blood alcohol levels.

STRESS MANAGEMENT

  • Concept of Stress

    • Response to demands; relative to individual perceptions of ability against actual demands.

    • Can cause physiological and psychological effects impacting overall performance.

INFORMATION PROCESSING AND LEARNING

  • Cognitive Processing

    • Process includes sensory input, attention, perception, memory retrieval, and decision making, leading to actions.

BEHAVIOUR AND MOTIVATION

  • Maslow's Hierarchy of Needs

    • Includes physiological, safety, social, esteem, and self-actualization needs.

    • Understanding motivation dynamics impacting performance.

COMMUNICATION AND COOPERATION

  • Importance of Clear Communication in the Cockpit

    • Prevent misunderstanding and enhance crew cooperation; recognizing the impact of verbal communication and body language.

CREW RESOURCE MANAGEMENT (CRM)

  • Definition and Scope

    • Involves sharing knowledge and practices across various team members beyond just in-cockpit interactions to enhance overall safety.

FINAL NOTES

  • This module integrates extensive human factors themes, emphasizing the relationship between human performance and aviation safety.