Human Factors AI0826

Define Human Factors and what it looks at

Human Factors is the application of human sciences to understand human performance limitations and why errors occur, aiming to optimise the relationship between the human operator, technology, and the environment to enhance safety and reduce operational error/mistakes.

Define the Information Process Model and explain the four steps

Represents the basic principle of how an individual processes information in order to make a decision:

1. Sensation - Brain is fed data from our senses for it to process

2. Perception - Brain makes sense of the data by interpreting it.

3. Planning - Once the meaning of the data is understood, the brain can construct a plan of intended actions

4. Execution - Brain then instructs the various parts of the body to carry out the plan (there is potential for error)

Define the Reason Model and list the five levels

Also known as the Swiss Cheese model. A systems approach that describes a chain of events that leads to someone committing an unsafe act that triggers an incident. Series of errors line up throughout the levels to create window of opportunity for an incident.

High risk-low hazard environments

Defences - Inadequate

Productive Activities - Unsafe Acts

Preconditions - Psychological Precursors

Line Management - Deficiencies

Decision Makers - Fallible Decisions

List the symptoms someone with Hypoxia may exhibit?

An organ or part of body starved of enough oxygen at tissue level.

Sluggish thinking

Dimmed vision or visual changes

Poor or lack of judgement

Euphoria/unnatural feeling of well being

Mental fixation

Fingernails and lips become blue

Describe three ways of managing fatigue

Sleep - manage and maximise sleep. Dark, quiet, cooler

Exercise/physical fitness - Regular exercise

Nutrition - Don’t eat too much during night shift

Fatigue Risk Management - Stipulated by ICAO for all ATS providers

Define Visual Perception limitations and give some examples

We see what we expect to see, what our experience allows us to see, and what our physiology allows us to see.

Brain fills in gaps to understand something it is seeing.

Limitation examples

• Narrow field of vision (10-15d to focus/classify)

• Blind spots

• Depth perception (eg Snow)

• Can’t see in the dark (infra red)

• Can’t see through objects

Define Auditory perception limitations

We hear what we need to hear

What we expect to hear

What our experience allows us to hear

What our physiology and environment allows us to hear

Brain adds and subtracts information we are hearing until a logical conclusion is formed.

Define Physical Ergonomics and explain some ATC examples

The Physical fit between humans and their equipment. The aim is to accommodate as much of the population as appropriate (not just the average person).

• Lights reflecting on display screens

• Chair comfort and posture

• Distance from commonly used buttons and a swivel chair to reach them easily

• Standup desks

• Temperature of the work environment

• Background noise and distractions

• Shift length

What is Procedure Design and what considerations should be taken in their design?

Procedures such as SOPs help humans adapt to technological advancements. Acting as an interface between the variability of the biological behaviour of the brain and the rigid laws of physics governing technological systems. must be documented and subject to constant review.

for procedures to be well designed, consider:

• As simple as possible to follow

• Written as unambiguously as possible

• Important to ensure that the people using the procedures are properly training for their use to minimise misapplication

What are the two types of failures in the Reason Model

Latent Failures - Those built into the system. May have adverse effects hours, days or even years after error was made

Active Failures - Have immediate adverse effects

Define the Bystander Effect

The more people there are, the less responsibility any individual takes for a decision or action. Diffusion of responsibility - When you know others are present, individuals don’t bear the full responsibility, make an assumption that someone else will take care of that or has done something by now.

• May fear losing face

• Others are more qualified, obedience of authority

• Monitor reactions of other people

• May happen for crimes, but also at work or in normal settings (assuming someone else has done a procedure without confirming)

Describe the three types of communication and impact in ATC

Verbal - More than just spoken language. Includes pitch, emphasis, volume. In ATC, unclear speech/phraseology can result in incorrect interpretation of clearances/readbacks.

Non-Verbal - Body language, para language (dress, stance, movement), environment. These affect how the nature of a situation is perceived by controllers.

Written - Written word, email, text, strip writing. In ATC, unclear strip writing can pass incorrect information between controllers. Incorrectly interpreted.

Describe some barriers to Communication

Age, Gender, emotional state, communication style, personality, emotional state, culture, and differing worldviews, confirmation bias. Alter how information is expressed and interpreted.

In ATC it can lead to missed information, incorrect assumptions, poor conditions, or delayed action. Reducing safety margins.

How are Habits and Routine a good and a bad thing?

Good: Accessible in the brain without much effort (procedural memory). Protect against mistakes that come from boredom.

Bad: Can cause problems when situations deviate from normal and the habit/routine is no longer applicable, requiring last minute thinking/problem solving. People tend to fall back on well learned responses even when no longer appropriate.

Experienced: Tend to perform actions and behaviours without much thinking, relying on habit/routine.

Inexperienced: Tend to have to think about every action before doing it before it becomes well learned. Faster reaction times.

What are the three types of error classification?

Skill based - Precede a problem. Rely on stored routines and motor skills, mostly automatic with little thought required. Doing something unintended by failing to monitor routine actions at critical points via too much or too little attention to the action at hand (Slips).

Covert errors such as forgetting to do something. Usually invisible and memory related (Lapses)

Rule based - Mistakes when attempting to find a solution for a recognised problem. Miss classification of the situation leading to the wrong mental rule being applied, or incorrect recall of procedures. Subtle/hard to detect. Miss application of good rule or application of bad rules.

Knowledge based - New situations with no pre-existing rules to fall back on. Problem solving. Keep making attempts. Error accuses with inadequate knowledge or misapplication of knowledge. Selectivity focus on wrong part of problem, and biases.

Define three types of Bias?

Confirmation Bias - When making quick decisions, we serve for evidence to support that decision but tend to ignore evidence that is contrary to the decision. We notice/seek information that proves us right rather than information that proves us wrong and are reluctant to change our decision. 

Availability Bias - When faced with a problem with a time limit, more weight is given to information that comes easily to mind, ignoring or thinking less of information that does not. Often most vivid, frequently or recently used. 

Continuation Bias (Entrapment) - Natural urge to continue with the plan already decided on and simulated. Less mental effort required to continue with current than to change. Can continue down a path even if it is not working. Fatigue, culture, ego etc. 

What are decisions based on and what influences them?

Decisions are made based on information from the environment and the information from memory. 

Decision making is influenced by:

• How information is presented

• The reliability and clarity of information 

• Use of negative evidence (ignored because it “can’t be right)

• Biases in thinking

What is TEM and how is it applied to ATC?

What is Threat and Error Management: TEM is a framework for understanding the relationship between human performance and safety. It focuses on managing threats and errors rather than preventing them, recognising they are part of everyday operations and must be managed to maintain safety margins. It acts as another defence within the Reason model.

The TEM model is viewed from the ATC view of threats, errors and undesired states.

How is TEM applied by ATCs: Controllers continually identify and manage threats, detect and correct errors, and recover from undesired states before they develop into unsafe outcomes. The aim is to maintain or restore safety margins at each stage over assuming threats/errors can always be prevented.

Define the four states of TEM

Define the 4 states of TEMS:

• Threats - Event/error outside the controller's influence that must be managed to maintain safety (eg incorrect readback)

• Errors - Controller action/inaction deviating from intention/expectations, (eg missing an incorrect readback).

• Undesired states - Unintended traffic situation results in a reduction in margins of safety. (e.g. An aircraft climbing or descending to a different flight level than it should)

• Outcomes - The final consequence, particularly a reportable incident or accident (eg loss of separation).

Define Situational Awareness and how it can be eroded/regained

How aware we are of the world around us (in ATC, how aware we are of the ATC situation).

Three levels of SA:

• Level 1: Perception of elements in the environment 

• Level 2: Comprehension of the current situation 

• Level 3: Projection of future status* 

SA Eroded by:

• High workload tying up short term memory

• Distraction 

• Incomplete or inappropriate information 

• Reliance on automation 

• Lack of motivation

• Use of non standard procedures

SA Gained by:

• Removing the causes (e.g. distraction)

• Training, Experience and intensive consistent practice 

Define No-Blame Culture vs Just Culture

No-Blame Culture - Pros, encourages error reporting without repercussions. The vast majority of unsafe acts were honest mistakes (slips and lapses). Not blameworthy. 

Cons: Ignored those who wilfully and repeatedly engaged in dangerous behaviours, increasing risk of errors. Also, did not distinguish between culpable and non-culpable unsafe acts. 

10% culpable. 

Just Culture - Negotiate where the lines should be drawn for unacceptable behaviour and blameless unsafe acts, and handle the grey area on a case by case basis.

What is safety culture?

Safe Culture - Where safety is a major concern, a culture that nurtures safe practices positively affects the safety performance of that organisation. Characteristics of Safe Culture include: 

• Mindful of danger

• Accepts setbacks

• Committed

• Reviews events to collect data

• Improve defence

• Recognises institutional factors

• Prioritises safety over money

• Encourages reporting by not blaming honest mistakes.

Define the SHELL model components and give examples

Adopted by ICAO to differentiate between sub systems of the aviation system and identify how their interaction is influenced by human capabilities. Considers how the software, hardware, environment, and liveware of the aviation systems interfaces with the human user. 

Software - Procedures: AIP, symbols, strips, documented procedures

Hardware - Machines and equipment: Headsets, keyboards, screens etc. 

Environment - Internal and external to workplace: Noise, comfort, lighting, culture

Liveware - People: Team, management, pilots

   H

S L E

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How the Hardware, Software, Environment, and other Liveware of the aviation systems interfaces with the human user (Liveware)

Examples

• Liveware - Software: Computer giving ambiguous information. 

• Liveware - Hardware: Ergonomics, Seat design to fit sitting characteristics of the human body

• Liveware - Environment: Weather, glare, lightning

• Liveware - Liveware: Between people, teamwork, leadership.

Why are human senses and perceptions unreliable?

The brain does not simply record sensory information; it interprets and reconstructs it using expectation, experience, physiology and the environment. This can cause incomplete/incorrect visual/auditory illusions from our brains adding/altering information to create an interpretation that isn’t necessarily correct.

What are the primary parts of the Stress curve?

Underload is when the stress level isn’t enough to keep someone engaged, reducing performance.

Eustress is when the situation creates a comfortable amount of stress which can help us adapt and increase performance.

Distress (overload) is when someone can’t handle the demand and finds it debilitating, decreasing performance.

Describe some biases in Decision Making

Biases in Decision Making

• Frequency - Risk of event occurring is over or under evaluated due to reference to personal experience.

• Association - Preference to select information which is logically linked. 

• Expectation - Tendency to choose the most familiar decision 

• Conformity - Look for results that support our decision rather than contradictory results.  

• Group Think - Group pressure, go with the crowd on a decision. 

What are two common types of ATC decision making styles?

Two types of ATC decision making styles

• Surfer - Fun, highly efficient, sometimes risky, attention highs and lows. 

• Conservative - Basic and safe, more constant attention.

Why is overload bad and how can you manage it?

Overload can degrade attention and working memory, causing information to be missed, delayed, or processed incorrectly, with responses becoming less precise or revert to habitual behaviour. It is only recognised after performance has already begun to deteriorate, and the signs can be subtle enough that others may also fail to notice them quickly.

Prioritize critical tasks, deliberately filter or queue secondary inputs, and avoid overloading the same perceptual channel.

Support your working memory by chunking information, rehearsing key data, and using written cues or reminders for deferred tasks.

Finally, if mental capacity is exceeded, immediately communicate the overload to secure support and maintain safe operations.

What are the three main memory types?

Sensory

Iconic - Monitor environment. Memory stored for 0.5-1 sec, lost if not attended.

Echoic - Auditory information stored for 2-8 sec, can be recalled up to 4 sec and even verbalised without processing. 

Working (short term)

Articulatory loop (verbal or auditory loop) & Visual-spatial scratchpad

Capacity is fairly limited, when full attention is devoted to rehearsal the brain can remember 7 +/- 2 items. This can be expanded by methods such as ‘chunking’.

Long term

Declarative (Facts/information) & Procedural (Knowing how to do it)

Limitless capacity

Define some memory limitations

High workload limitations - Increases the amount of information competing for limited working-memory capacity. Once capacity is exceeded, information is more likely to be lost, confused or transposed, and attention becomes less effective.

Working/Short Term memory - The maximum number of unrelated items, which can be maintained when full attention is devoted to rehearsal, is 7+/-2. Once the limit is exceeded, items are likely to be lost or transposed.

Challenges of Two Tasks - Two tasks using the same perceptual domain interfere strongly with each other and reduce performance. Tasks using different systems, such as one visual and one verbal task, can theoretically be performed together more efficiently because the visuo-spatial and phonological systems are separate.

Prospective Memory - Prospective memory is “remembering to remember”, making an intention to perform an action later, often after a delay or interruption. It is important in ATC because controllers are frequently forced to postpone tasks and must remember to complete them later.

Link the intended action to a clear cue, such as a time, duration or event. External reminders such as lists or notes can also help. Prospective forgetting is more likely when the task seems unimportant or boring, or when there is little time available to encode or retrieve it.