Human Factors Integration and Human Centred Design Concepts

Diploma in Aviation Medicine:Human Performance

Revision June 11

Objectives of Aviation Psychology

• to enhance flight safety

• to improve effectiveness

Why is There Interest in Human Performance in Aviation?

• Aviation is a safety-critical operation• Aircrew are subjected to many sources of stress• High levels of human performance must be achieved (e.g., fast jet pilots)• Human error is heavily implicated in aviation accidents

Main fatal accident causes in 1994

Accident cause Accidents (%) Fatalities (%)

Air crew error Controlled Flight into Terrain Weather Loss of Control Engine Failure/Fire Structural/System Failure

65 37 30 14 16 11

68 43 24 34 7 13

Equipment& tasks

Environment

Otherpersonnel

Humanoperator

The Human in the Aviation System

Content of Human Performance Module

General Principles • Introduction to Human Performance Module• Fundamentals of Human Performance• Individual Differences• Social Psychology and Aviation

• A small amount of basic theory to help you to interpret the practical studies


New this year! • An early session on human error

• …to provide a context for the module


Personal & Environmental Factors Stress & Workload in Aviation I Stress & Workload in Aviation II Perceptual Issues in Aviation Situation Awareness Selection of Aviation Personnel


Training and Simulation Simulation and Training Fundamentals of CRM Training Practical Aspects of CRM & LOFT


Systems Factors Aviation Ergonomics I Aviation Ergonomics II


The Human Factor in Aviation AccidentsSeminar: Flight Safety

– Prof Peter Jorna, former head of division at NLR Amsterdam

Also an accident module at Henlow, providing a context for this moduleSee also lectures on Sleep, Fatigue and Shift-Working

Equipment& tasks

Environment

Otherpersonnel

Humanoperator

The Human in the Aviation System: Relevance of Module Topics

SelectionIndividual

Differences

Equipment& tasks

Environment

Otherpersonnel

Humanoperator


ErgonomicsWorkload

Technical Training

Equipment& tasks

Environment

Otherpersonnel

Humanoperator


StressPerception

Equipment& tasks

Environment

Otherpersonnel

Humanoperator


CRM Training

Equipment& tasks

Environment

Otherpersonnel

Humanoperator


‘SituationAwareness’and ‘Human

Error’ encompass all these interactions

Human Information Processing

Cognition

Processes involved in the input, storage, transformation, and output of information by humans

Main topics:

• Memory

• Attention

• Skills

Memory

Three major memory systems:

• Sensory memory

• Short-term memory

• Long-term memory

Summary of properties of memory systems (inferred from classicexperiments on memory) learn this!

Sensory Short-term Long-term

Capacity High 72 chunks no knownlimit

Duration 1 sec 10-15 sec permanent?

Type of storage Physical acoustic semanticcharacteristics

Nature of retrieval parallel serial hierarchy?

Nature of forgetting decay/maskinginterference failure ofretrieval

Attention

Selective attention: attend to one of several competing sources of information

Divided attention: attempt to attend to more than one information sourceor task at the same time

Shadowing taskCan detect physical changes on the unattended channel, but not semantic content

Dichotic listening taskPerformance very poorSubjects tended to organise their recall by ear, not by recency of presentation

Led Broadbent to propose Filter Theory. But, later shown that• subjects tend to hear their own name on the unattended channel• subjects tend to follow the message, even if it switches ears• hence, there is semantic processing on the unattended channel

However, we can assume that recognition of unattended information is less likely than recognition of attended material

Make sure that you understand this!

Divided attention

Key question:

Does man have a single information-processing channel (all tasks compete for the same ‘resources’ or ‘capacity’)

or

specialised resources for particular types of activity? (tasks performed concurrently compete only if they draw upon the same resources)

Some support for the multiple resource theory: often, the degree oftask interference depends upon the similarity of the tasks

But: sometimes tasks that are dissimilar are found to interfere

Baddeley’s working memory model is a compromise between extremesingle-channel and multiple-resource views

Central Executive

Visuo-spatial scratchpad

Articulatory loop

Skills (obviously relevant to training lectures!)Characteristics• typically a sequence of activities• goal-directed behaviour• use of feedback

Skill acquisition

Three phases are sometimes distinguished:• Early or cognitive phase• Intermediate or associative phase• Final or autonomous phase

In the final phase, behaviour becomes automatic; delegated to thecontrol of ‘motor programs’ that do not require conscious attentionand do not place heavy demands for mental resources

Many everyday errors (actions not as planned) are associated with overlearned behaviourThese errors involve well-practised behaviour, but are inappropriateSome aircrew errors are of this type

Issues in skill acquisition

• Whole versus part learning

• Massed versus spaced learning

• Transfer of training very important aspect of simulator-based training

Individual Differences

Two major types of individual difference covered: Intelligence/ability/aptitude

Personality

Factor Analysis: make sure that you have a good intuitivegrasp of this: you don’t need to know the underlying mathematics!

Basic psychometric criteria

Intelligence/ability/aptitude These are the key issues

Intelligence: Innate or learned?

Intelligence: How many abilities?

• There is evidence for a general ability factor• However, specific abilities also appear to exist

Intelligence: The Intelligence Quotient (IQ)

Aptitudes

Test Fairness

Intelligence: Are IQ tests valid?

Personality key issues

Types of personality test: Interview (not reliable) Projective tests Personality questionnaires

(discussed examples of each)

Is there a ‘pilot personality’?

Does personality influence success in flying training?

Is there an ‘accident-prone’ personality’?

Social Psychology

Types of social influence (can use this info for CRM questions)

Compliance: behaviour consistent with direct request• foot-in-the-door phenomenon• door-in-the-face phenomenon Conformity: behaviour consistent with group norms• size of group (up to about four)• attractiveness and status of group members• Informational influence (trusting others’ judgements) and normative influence (seeking group acceptance) Obedience to authority • Milgram experiment• 62.5% of the 40 subjects administered shocks to the highest level• factors affecting obedience, such as status of experimenter, proximity to ‘student’

Think about how this applies to small groups of interest to us,such as flight crew or teams of maintenance engineers

Group Decision Making: Polarisation

• Was thought that group decision making was more risky than individual DM (‘risky shift’) — but became apparent that there is a shift in the direction of the pole that, on average, the group favours as individuals (polarisation)

• Stoner’s experiments

• Normative and informational influences produce group polarisation

Group Decision Making: Groupthink• Work of Janis. Based on real-life examples such as Bay of Pigs (or, more

recently, UK MPs’ expenses!)• Desire for consensus overrides group members’ motivation to assess risk

and consider alternative courses of action

• Groupthink occurs under the following conditions:• High cohesiveness of the group• Uncertainty of approval• Insulation of the group• Directive leadership• High stress situations

• Symptoms include• Illusion of invulnerability• Stereotypes of out-group• ‘Mindguards’• Direct pressure on dissenters• Collective rationalisation

• Effects on decision making:• Incomplete survey of alternatives• Incomplete survey of objectives• Incomplete analysis of risks associated with course of action• No contingency plans

Aeronautical Decision Making (ADM)• Work of Jensen: decision error is cause of most fatal aviation accidents;

argued that decision making can be improved through training

• Decisions have two components:• Rational judgement (‘Headwork’)• Motivational judgement (‘Attitudes’)

• Hazardous attitudes:• Anti-authority• Resignation• Impulsivity• Invulnerability• Macho

• ADM courses aim to provide:• Ability to recognise hazardous attitudes• Knowledge of effects of these attitudes • Skills to overcome the effects

• Methods• Self assessment tools• Examination of case studies• Practical Exercises

Perceptual Issues in Aviation

Perception is the process of acquiring, selecting, and organising sensory information

The most important perceptual processes for aviation are those associated with vision and hearing

1 The ear and the auditory system– balance and the vestibular system– localisation of sound and identification of source

2 The visual system– bottom-up processing– top-down processing– cues to depth perception

The ear and the auditory system

Balance. The vestibular system of the inner ear detects angular and linear accelerations of the head

Hearing. To detect sounds, to determine the location of their sources and to recognise the identity of these sources

The ear serves two main functions:

Practical implicationsBalance and the vestibular system

Accelerating aircraft

The situation is aggravated if the pilot attempts to compensate for an incorrect percept. Although feedback from the vestibular system can be compelling, a pilot needs to learn to trust instrumentation.

With regard to the otolith, the weight force in a climbing aircraft operates similarly to the resultant force in an accelerating aircraft. Without visual feedback, pilots can mistake acceleration for pitch.

Ascending aircraft

Weight force

Inertia force

Resultant

Localisation of soundAuditory perception

Interaural differences:•Intensity. Most suited to localising high frequencies

•Time/phase. Most suited to localising low frequencies.

Sounds emanating from directly in front and behind the head produce the same interaural differences.

Practical implications Cockpit design

– The cockpit relies heavily on the presentation of visual information. Adoption of auditory signals may reduce the workload experienced by pilots in the visual domain.

Localisation of auditory warnings– Similar sounding warnings emanating from similar

areas may cause confusion– Adoption of white noise bursts within ambulance

sirens

Auditory perception

What you see is what you get?Visual modality is obviously extremely important in aviation. But can we always trust our eyes?

The visual scene is captured by the eye as a poor quality, two-dimensional representation

What is perceived is determined by:‘Bottom-up’ processes. The percept of a stimulus is determined by features of the stimulus as processed by the visual cortex‘Top-down’ processes. The interpretation (consciously or not) of a stimulus can be determined by our experience and knowledge

Important distinction!

Visual perception

If the percept is generated deterministically (bottom-up processing) from the visual cortex . . .

. . . how can one distal (real world) stimulus produce two percepts?

By a mental model: Our own experience and expectations help to determine what we see (top-down processing)

Old or young women?

Thirteen or ‘B’?Necker cube

Lincoln or women?

Top-down processesVisual perception

Convergence– of the eyes.

Stereopsis– disparity between the

two images. Accommodation

– of the lens. Retinal versus actual size

– for known objects. Overlap

– a near object will occlude the view of a far object.

Position in visual field– objects nearer the horizon

are farther away. Aerial Perspective

– clarity of objects is reduced at distance.

Relative motion– angular velocity greater for

near objects.

All require both bottom-up & top-down processing.

Depth perception: learn this!Visual perception

44

• Position in visual field• objects nearer the horizon are farther

away

• Textual Gradient• Surfaces will have a finer texture with

distance

• Stereopsis• Binocular disparity between the two

images

• Convergence• of the eyes

• Occlusion• a near object will occlude the view of a

far object

• Perceptual constancy• Retinal versus actual size

• Relative motion• angular velocity greater for near objects

• All require both bottom-up & top-down processing.

How we perceive depth

Know this

Featureless surfaces, or those with textures of unknown sizes, can produce inaccurate judgements of size.

– Sea.– Beehives for caravans.

Can produce an inaccurate mental model of the situation which overrides the correct perception of the instruments.

– Top-down influences.– Exacerbated by fatigue and workload.

Some perceptual problemsVisual perception

Pilots may have to visually judge the glide slope without any cues other than those from the surface of the world.

The ‘aspect’ (retinal shape) of the runway is not very useful.

However, the visual touchdown point is a constant and unchanging cue, relative to the horizon.

If the horizon cannot be seen, its location must be implied,– The runway’s sides meet at the horizon.– The terrain’s texture gradients.– The relative position of the aircraft’s canopy.

Practical implications: visual approach

Visual perception: know the practical implications (next few slides)

Visualtouchdownpoint

HORIZON

A

B

Angle of Approach A = B

Practical implications: visual approach (2)Visual perception

= angle of approach

Visualimpactpoint

Actualtouchdownpoint

Practical implications: visual approach (3)Visual perception

Identification of a colliding aircraft is confounded by;– Constant relative bearing.

• Unique characteristic.• Periphery of retina detects sensitive to movement.

– Non-linear increase in retinal size.• Retinal image doubles with each halving of closure

distance.– Uneven visual acuity across the retina.

• Maximal acuity at the fovea.• Detection only if pilot is looking directly at it.• Implications for visual scanning to acquire proximal

image on the fovea.

Practical implications: mid-air collisionsVisual perception

Aircraft A

Impact

Aircraft BRelative Bearing

Practical implications: mid-air collisions (2)Visual perception

3 secs / 0.5 degree

1.5 secs / 1 degree

0.1 secs / VERY BIG

Practical implications: mid-air collisions (3)Visual perception

Bottom-up (information from our senses) and top-down (expectations and experiences) processes affect the way we perceive the world.

The resultant perception is often not a true reflection of the external world.

This can be advantageous when it is in our interest for differences between features in the external world to be exaggerated but potentially catastrophic when perceptual illusions lead us to take inappropriate behaviour.

SummaryPerception

Ergonomics

Why ‘Ergonomics’? – Murrell

The HSI Framework – seven domains– Manpower– Personnel– Training– Human Factors Engineering (aka Ergonomics)

• Workplace design• Anthropometry• Critical Dimensions

– System Safety– Health Hazards– Social & Organisational

HSI often called Human Factors Integration (HFI) – HFI is really the process by which HSI is applied to equipment procurement

Some people adopt a strict definition of ergonomics; others treat all of HSI as being within the scope of ergonomics. You would not be penalised for adopting the latter definition!

Tragic consequences

Kegworth

USS Vincennes

Herald of Free Enterprise

Chernobyl

Three Mile Island

HSI Domains KNOW THESE

Manpower: numbers of personnel required to operate, maintain, sustain, & train to deliver capability (e.g. aircrew complement)

Personnel: cognitive/physical capabilities required to train for, operate, maintain, sustain system

Training: instruction/education/ training to provide job skills, knowledge, values, and attitudes (different methods summarised)

Human Factors Engineering (aka Ergonomics)Workplace designAnthropometryCritical Dimensions

Systems Safety: applying HF expertise into programme Safety Management Process

Health hazards: conditions inherent in the system that may cause injury or reduce performance or well-being

Social/organisational factors: applying techniques from organisational psychology, social sciences, information science, and system of systems

Human Factors Engineering(aka Ergonomics)

focused on the integration of human characteristics into system definition, design, development, and evaluation to optimise human machine performance under operational conditions.

Workplaces & interfaces Cockpits Workstations Control rooms Offices Transport systems Factories

Controls Displays Computer hardware Computer software Protective clothing Other people

Physical workplace design Inputs required from

– EHFA– Task analysis– Link analysis– Allocation of function

Consider– Operational and environmental context– Human dimensions– Biomechanics and physiology

Functional factors Task issues

– Procedures– Critical elements

Responsibilities of organisation and individuals Communications

– Verbal– Non-verbal

Visual issues, such as sight lines Flows of materials and personnel Access and clearance

– Normal– Emergency– Maintenance

Protection– Protective clothing & equipment– Barriers & guards

Anthropometry Physical human dimensions Population specific Linear dimensions, for example:

– Stature– Functional reach– Sitting height

Girth dimensions, for example:– Waist – Head circumference

Each dimension is expressed in terms of percentile

Be careful with percentiles when applying anthropometry

Requirements often state …must accommodate the 5th percentile and the 95th percentile human…

But, these people do NOT exist!

Critical dimensions Choose dimensions relevant to the workstation,

posture, and task– Sitting, standing, reach, fit, walking, crouching

5th percentile (smaller) dimensions considered for:– Seat adjustment, reach, vision, control movement, foot

rests 95th percentile (larger) dimensions considered for:

– Seat adjustment, ingress, fit, access, clearance

Clothing Clothing increases most dimensions through the

addition of bulk– e.g. stature, sitting height, chest depth, shoulder

breadthBut Decreases the reach dimensions due to restriction of

movement– e.g. functional reach, vertical functional reach

When to integrate Human Factors

(Eurocontrol, 1999)

HSI “Designed” to Fit MoD’s Acquisition Operating Framework (AOF) Policy and Good Practice

CADMID cycle System Readiness Levels

(DEF STAN 00-250. May 2008; http://www.aof.mod.uk ; www.hfidtc.com )

MoD JSP to be introduced later this year

Concept Assessment Demonstration Manufacture In service Disposal

Initial Gate Main Gate System Acceptance

Has now happened

http://www.aof.mod.uk/

http://www.hfidtc.com/

Summary HSI covers all aspects of applied human factors Human Factors Engineering is just one element that

needs to be integrated HSI comprises tools and processes that fit with

systems engineering HSI is widely applicable Early inclusion is so much better than late

intervention

Stress and Workload

Types of stress

• Life stress less important than the others in this context, but be aware of it • Environmental stress • Cognitive stress

Life stress

Typically measured by questionnaire

Some correlation between questionnaire scores and illness

Some evidence that life stress is associated with accidents

Level of arousal

Performance

Yerkes-Dodson law: Know this

Inverted U relation between arousal and performance

Performance declines as arousal increases or decreases from the optimal level

The optimal arousal level is inversely related to task difficulty

Difficulttask

Easytask

Environmentalstress

Fear• disruption of manual dexterity• disruption of secondary task performance

Noise• greater effect on difficult tasks• effect on error• increased attentional selectivity• effect on arousal (increases initially, then returns to normal)

Sleep loss• periodic lapses• decreased attentional selectivity• greater decrement on ‘easy’ tasks• decreased arousal

Hypoxia• performance affected at over 10,000 ft • some evidence that task learning is affected at only 8,000 ft

Combined stressorsSleep loss and noise each impair performance in isolationHowever, noise improves the performance of sleep-deprived individuals

Know this

Patterns of effects of stressors (from Hockey)

Stressor Arousal Selectivity Speed Accuracy STM

Noise + + 0 - -Anxiety + + 0 - -Incentive + + + + +Stimulants + + + 0 -Heat + + 0 - 0Alcohol - + - - -Sleep loss - - - - 0Fatigue- + - - 0Depressants - - - - -

+ increase- decrease0 no effect

no need to memorise all this, but know that each stressor has its own pattern of effects (cannot be explained by Yerkes-Dodson law)

Personality and stressKnow this

Two major dimensions of personality are:neuroticism (trait anxiety)introversion-extraversion

Introverts are chronically over-arousedExtraverts are chronically under-arousedAn arousing stressor (caffeine) has different effects on these individuals

Trait anxiety comprises worry and emotionalityWorry appears to interfere with task performancePerformance of high-anxiety subjects impaired under high workload

Evidence that personality influences success in flying training

Is the Yerkes-Dodson law adequate? Know this

For:

• Can explain effects of combined stressors

• Can explain some effects of personality

• Can explain some effects of task difficulty (e.g. greater effect of sleep loss on easy tasks)

Against:

• Does not explain specific patterns of effects of individual stressors

• Does not explain effects on attention

• Too flexible: does not lead to firm predictions

Factors influencing the effects of stressors know this

• Task difficulty

• Task duration

• Personality

• Intensity of the stressor

• Motivation

• Importance of the task component

• Presence of other stressors

Workload (cognitive stress) know thisTypes of workload measure

Subjective Example: NASA Task Load Index • easy to obtain• face valid• unobtrusive• subjects can readily quantify their experience

Physiological Example: heart rate variability• do not disrupt performance• often provide continuous record

Performance-based Primary task or secondary task (e.g. time estimation)• provide direct measure of operator performance

• difficult to establish which questions to ask (dimensions of workload)• difficult to compare different types of task• ratings may not be correlated with task performance

• equipment may be physically intrusive• only indirect indication of performance

• operator may invest more effort to maintain primary-task performance • choice of secondary task is important

Effects of high workload

• operator is prone to actions not as planned: unable to monitor activity fully• increased attentional selectivity• may respond quickly but inaccurately• may shed some sub-tasks completely

Strategies for workload reduction [know this]

Change the task:apply sound ergonomic principlesautomate some functionsuse new technologies

Change the operatorprovide extensive training, to produce motor programs (overlearning)

Personnel selectionfor example, low trait anxiety may confer betterability to cope with high task demands

Selection

Aims:

Deciding • What to measure• How to measure• Effectiveness of measures

Stages in Selection System

Specify selection criteria

Specify assessment methods

Evaluate

(After Hunter & Burke 1995)

The Systems Approach to developing selection processes.

1. Job / Competency analysis — Identify Knowledge, Skills and Attitudes (KSAs) required

2. Use KSAs to identify appropriate selection methods.

3. Establish the reliability and fairness of the process

4. Validate

Job Analysis

PersonRequirements

Aptitudes

Predictors

PersonSpecification

Job Requirements

TaskCompetencies

Criteria

JobDescription

Prediction

(After Hunter & Burke 1995)

Job Analysis

• Aim — Identify critical competencies required for successful job

performance

• Outputs — What does the job holder do?• Inputs — what skills, knowledge, abilities does the job holder need?

• Result is a competency framework identifying critical success factors associated with successful performance

• Why?1. To achieve the best possible prediction of job performance (put the

right people in the job)2. Legal requirement – test fairness

Types of Job Analysis

1. Hierarchical task analysis (Annett, Duncan et al 1971)

2. Functional Analysis (Fletcher 1991)

Techniques: Critical incidence technique (CIT) (Flanagan 1954*)

• Identify key roles and functions of job• Identify critical behaviours (related to success or failure)• Classify into similar behaviours• Summarise• Validate using other SME

Other techniques include Repertory grid

Classifying Aptitudes

Fleishman’s Taxonomy of Skills

Abilities were classified into:• Cognitive: Information processing and problem solving• Perceptual/spatial: Attention and spatial orientation• Physical: Flexibility, strength and stamina• Psychomotor: Coordination and reaction time

NATO Study: Aptitude dimensions for military fast-jet pilots (Bydorf 1993)• Situational awareness: Perceptual closure + reaction time• Spatial orientation• Time sharing• Aggressiveness• Divided attention• Psychomotor coordination• Perceptual speed• Selective attention• Visualisation

Weighting Aptitudes

Determining priorities

• Need to identify relative importance of aptitudes in job performance

• DIF Analysis. Ratings of:• Difficulty• Importance• Frequency

Choice of Measure

LifeExperiences

Ability Motivation Temperament

Performance

CV; BiodataInterview

Personality QuestionnaireGroup exercises

•Occupational Interest Inventories; •Measures of

personal values•Interview

• Psychometric tests• Work sample tests

• Physical tests

Types of aptitude measure• Paper & pencil measures

• Computer-based testing: BARB (British Army); OASC (RAF); MicroPat (AAC, RN, BA, Cathay); TASKOMAT (Commercial); BAT (USAF)

• Ease of administration• Experimental testing• Dynamic measures possible• Measure processing capacity• Multi-tasks• Sophisticated measures such as response latency

• Work sample • RAF Flying Grading

• Simulation based•Advantages of CBT & work sample• Lower costsExample: Canadian Automated Pilot Selection System

• Biodata

• Personality measures see other lectures

Effectiveness of measures

Evaluating Selection: Reliability and Validity

Reliability Accuracy and stability of the test• Internal consistency reliability• Split-half reliability• Parallel forms• Test-retest reliability • Inter-rater reliability

Validity Does the test really measure what it claims to measure?• Construct validity • Content validity • Predictive validity

See other lectures as well!

Predictor score

Perf

orm

ance

sco

re

FalsePositivesTrue

Negatives

TruePositivesFalse

Negatives

Cut-off score

‘Pass Mark’

Error in allocation

Predictor score

Perf

orm

ance

sco

re TP

FPFN

TN

Higher Correlation reduces error

Predictor score

Perf

orm

ance

sco

re

Cut-off score1

‘Pass Mark’

Cut-off score2

Effect of setting Cut-off scores

Great 8 Competency Factors Overall job performance Leading and deciding 0.35 Supporting and co-operating 0.23 Interacting and presenting 0.30 Analysing and reporting 0.35 Creating and conceptulising 0.42 Organising and executing 0.45 Adapting and coping 0.25 Enterprising and performing 0.37

Average Correlation between competency ratings and job performance

Interpreting scores• Norm referenced — most cognitive/ability tests

• Self referenced — Attitude/Personality measures• Criterion-referenced — job skills

Validity of Different Methods

Selection Method Mean Validity Co-efficient

Interview - Unstructured 1

Interview - Structured 2

.14

.35

Biodata 1 .37

References 3/1 .17 to .26

Cognitive ability testing 4/1 .25 to .53

Personality testing 1/5

Work-sample tests 1

Trainability tests 6

.10 to .33

.54

.46

Example: RAF Aircrew Selection

READY TO CHANGE YOUR LIFE?Your visit to OASC will take several days and includes:• an initial briefing;• aptitude tests;• an aptitude test review;• the exercise phase;• an interview;• an occupational medical; and• fitness assessments. (from OASC brochure)


ADPO10369 EVOLUTION OF APTITUDE TESTING IN THE RAF M. Bailey, RAF Cranwell

Before 1940: main method was unstructured interview

About 50% pilot training failure rate at start of WWII

First set of Aircrew Selection Board tests included• Essay writing• Elementary maths• General intelligence

• Early developments• need recognised for separate tests of skills and personality• shift to testing for specific roles (e.g. electromechanical coordination)• 1944: With help from USAAF, series of objectives measures (e.g. 24 aptitude tests for six aircrew categories) – waste down from 48% to 25%• use of specially trained staff


1944–84Many more tests created – but at the end of this period tests were not markedly different

Preliminary Flying School closed 1974 – selection then relied purely on aptitude tests. For various reasons validities dropped; for example, to .14 for training results

Second generation selection tests: • exploited increased computing capability:

• at first, computerised versions of existing tests• later, new tests (based on abilities required, using Fleishman’s system) – Air Traffic and Fighter Controller Test Battery produced

• Nine weighted test scores used• Good predictive validity

Issues• No formal job analysis• Tests driven by theory and test availability

Hence 1990s:• Shift to domain-centred framework


:

Simulation and Training

Information from

• skill lecture

• simulation and training lecture (technical skills)

• CRM lecture (non-technical skills)

• Human error lecture

• etc

Key Issues

• Training needs analysis (organisational, occupational, individual) — focus on Knowledge, Skills, Abilities/ Attitudes (KSAs) Design of training programme

• Develop Instruction by Objective• Select Instructional Strategy• Select/ organise element to be trained• Identify training aids• Organise materials/resources• Apply learning principles• Develop Evaluation Instruments

• Implementation (who, where, when)

• Evaluation (Reaction, Learning, Behaviour, Results) • Note DIF analysis (difficulty, importance, frequency) — helps to decide whether not to train, to train, or to over-train

Training issues (see also Human Information Processing lecture):

• Massed versus distributed practice

• Whole- versus part-task approach

• Phases of learning

• Feedback Media and technology

• Simulation — very important in aviation, where the objective is to maximise the transfer of learning from simulator to aircraft; fidelity is a key issue: do not need physical fidelity (simulator does not need to resemble the aircraft), but functional fidelity is important

• Internet-based — increasingly important; can be accessed even in the field

• Traditional — still some role for classroom-based instruction

Situation Awareness

Topics

Definitions Models Theory Metrics Applications Limitations

Leading causal factor in a review of 175 aviation mishaps

Hartel, Smith and Prince

(1991)

Major causal factor in 88% of accidents associated with human error in a review of major aircraft carrier accidents (1989-1992)

Endsley(1994)

Controlled Flight Into terrain (CFIT) accidents killed 5000 people between 1978 and 1992. 74% of these accidents were due to loss of flight crew SA

Woodhouseand

Woodhouse(1995)

Why is Studying Situation Awareness Important?

SA popularised to describe the psychological processes of:– Attention– Memory– Perception– Prediction– Pattern Matching

Historical Origins of SA

‘‘Mental Model’Mental Model’of the situationof the situation

Definitions of SA 1

“ . . . Knowledge of current and near-term disposition of both friendly and enemy forces within a volume of airspace.” McMillan McMillan (1994)(1994)

“. . . One’s ability to remain aware of everything that is happening at the same time and to integrate that sense of awareness into what one is doing at that moment.” Haines & Flateau (1992)Haines & Flateau (1992)

“. . . A pilot’s continuous perception of self and aircraft in relation to the dynamic environment of flight, threats, and mission, and the ability to forecast, then execute tasks based on that perception.” Hamilton (1987)Hamilton (1987)

Situation Awareness is . . .

A Working Definition of SA

Situation Awareness is . . .

– “The perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future” Endsley (1988)Endsley (1988)

– It is derived from the aircraft instrumentation, the out-the-window view, and his or her senses

– The quality of an operator’s SA is moderated by individual capabilities, training, experience, objectives, and the ability to respond to task workload

– The term ‘SA’ should only ever be applied to dynamic environments

Summary know this

When all is said and done we know that Situation Awareness refers to an operator’s knowledge and Understanding of the dynamic environment in which he/she is operating

It is knowledge of the ‘Big Picture’ SA provides the basis for subsequent decision

making and performance in the operation of complex, dynamic systems

PERCEPTION OF PERCEPTION OF ENVIRONMENTENVIRONMENT

COMPREHENSIONCOMPREHENSIONOF CURRENT SITUATIONOF CURRENT SITUATION

PROJECTION OFPROJECTION OFFUTURE STATUSFUTURE STATUS

A Model of SA

Level 3Level 3

Level 2Level 2

Level 1Level 1

Endsley (1995)Endsley (1995)

PERCEPTION OF PERCEPTION OF ENVIRONMENTENVIRONMENT

‘‘Perceive Perceive relevantrelevant

information’information’

COMPREHENSIONCOMPREHENSIONOF CURRENT SITUATIONOF CURRENT SITUATION

‘‘Integrate withIntegrate withtask goals’task goals’

PROJECTION OFPROJECTION OFFUTURE STATUSFUTURE STATUS

‘‘Predict futurePredict futureevents / statesevents / states

based on based on understanding’understanding’

SITUATION AWARENESS

Abilities Experience Training

System Capability Interface Design Stress & Workload Complexity Automation

Information ProcessingMechanisms

Long–term MemoryStores

Automaticity

Goals & Objectives Preconceptions

(Expectations)

Feedback

State of theEnvironment

Decision Performance ofActions

Task/System Factors

Individual Factors

Comprehensionof CurrentSituation

Level 2

Perceptionof Elementsin CurrentSituationLevel 1

Projectionof FutureStatus

Level 3

Endsley’s Modelbe aware of main elements

Model of SA in dynamic decision making (from Endsley, 2000)

SA

Environmental State

E.g. TemperatureTime Pressures

Day/nightNoise

Lethality

Operator Traits

E.g. IQCognitive AbilitiesConscientiousness

ExperiencePersonality

TrainingRisk Taking

Real World/SystemInformation

Salience of infoAvailability of info

Info complexityInfo quantityAutomation

Quality of HMI

Operator State

E.g. FrightenedConfused

High WorkloadFatigued

Aggressive

Goals

Mission GoalsSystem Goals

Personal Goals

QinetiQ’s Model of The SA Process

The SA ‘PROCESS’

The SA Process A series of complex cognitive

processes, including: Perception, Working Memory, Pattern Matching, Attention and Long Term Memory

NOT ‘task’ or ‘individual’ specific Also referred to as Situation

Assessment (SAS) Will be influenced by a multitude of

‘SA Factors’

These factors WILL BE ‘task’ AND ‘individual’ specific

Each factor will have different weightings or importance attached to it for differing military domains

The number of such factors is vast

Operator Traits

E.g. IQCognitive AbilitiesConscientiousness

ExperiencePersonality

TrainingRisk Taking

Environmental State

E.g. TemperatureTime Pressures

Day/nightNoise

Lethality

Goals/Doctrine/SOPs

Mission GoalsSystem Goals

Personal GoalsDirectives

ROECommander Intent

Knowledge/Information

Salience of infoAvailability of info

Info complexityInfo quantityAutomation

Quality of HMI

Factors Affecting the SA Process

Know the main headings!

The output of the SA PROCESS will be a number of ‘Situation Models’ (or dynamic mental models)

These situation models are essentially knowledge and understanding

The quality of a person’s SA is defined by the match between these situation models and reality Situation Model

Real World

The difference betweenthese represents the quality of one’s SA

SA as a Product

The person will have a situation model for each of the relevant ‘SA Information Domains’ associated with a specific task or job

Each SA information domain will comprise a number of ‘SA Elements’

Example: Endsley (2001) illustrates this for the task/job of piloting a civil aviation aircraft

Geographical SA•own aircraft•other aircraft•terrain features •airports•cities•waypoints•navigation fixes•position relative to

designated features•path to desired location•runway and taxiway assignments•climb/descent points

System SA•system status•functioning and settings

•radio•altimeter•transponders•flight modes and automation

•deviations from correct settings•ATC communications present•fuel•impact of degrades and settings

•on performance•time and distance available on fuel

Spatial/Temporal SA•attitude•altitude•heading•velocity•vertical velocity•Gs•flight path•actual values relative to assigned•projected flight path•projected landing time

Environmental SA•weather formations and movement•temperature•icing•ceilings•fog•Turbulence, winds•sun•visibility•IFR/VFR conditions•areas to avoid•flight safety•projected weather conditions

SA Elements

In Summary The development and

maintenance of SA occurs within an individual’s head

The SA process (or SAS) is a generic continuous process/cycle that is impacted upon by many factors

These factors will vary in their importance and influence depending upon the specific task and the individual undertaking that task

An individual will continuously cycle through the SA process for each SA Information Domain, developing a situation model for each

These situation models will be task-specific

All situation models will be continually updated and revised as new information becomes available or as the factors affecting the SA process change in importance or in state

Team SA SA can be applied to teams as

well as to individuals Caution needed here, as SA

cannot be shared (it resides inside the individual’s head), but information can be shared

We could be talking about:– 1) The overlap in SA for the team– 2) The SA of the team as moderated by

the primary decision maker– 3) The collective SA of the entire team

Measuring Situation Awareness

SA has become a major design driver– Developing operator interfaces to enhance SA– Developing automated systems without resulting in a loss of

SA– Training techniques are designed to develop better SA

Development of SA metrics for evaluation purposes– Development of metrics since the late 1980s– Varying degrees of maturity / validation – Various forms of metrics

• Subjective Vs Objective• Self-report Vs Third-Party rating• Simulator-based Vs Test flight

SA Metrics Crew SA SA Global Assessment technique (SAGAT) Snapshots SA Flight Training Evaluator (SAFTE) China Lake SA Scale (CLSA) SA Rating Technique (SART) SA Supervisory Rating Form (SASRF) Physiological Measures: Eye Activity

SA Metrics – Summary

SALevel

CrewSA

SAGAT SnapShots

SAFTE CLSA SART SASRF EyePOG

PerceiveEnvironment

ComprehendCurrentSituation

ProjectFutureStatus

Know at least SAGAT/SART in a little detail, plus names of a few others

SA Metrics – Summary

Most SA measures have been designed using a particular SA definition, and with a specific application in mind– Keep this in mind when selecting an SA measure

In practice, 2 of the SA measures outlined previously are used far more than the others:– SART (subjective)– SAGAT (objective)

This is probably due to the extensive validity data that accompanies these measures (we ‘know’ they are measuring SA)

There are three main military applications for SA research:– 1) System/interface design, development, assessment and

evaluation• Operator interfaces designed to enhance SA• Automated systems must switch without losing operator

SA– 2) Training operators to have better SA– 3) Selecting operators who are predisposed to having high SA

So, of What Use is SA Research?

Limitations of SA

SA is a theoretical construct– Practical difficulties in measuring and predicting SA– For those who do not understand the theoretical basics of what SA is all about, there can

be an element of perceived circularity

‘‘Why did the aircraft Why did the aircraft crash?’crash?’

Because of lack Because of lack of pilot SAof pilot SA

‘‘How do we know there How do we know there was a lack of pilot SA?’was a lack of pilot SA?’

Because heBecause hecrashedcrashed

Immature concept– Still much debate over definitions and measures

Crew Resource Management (CRM)

Introduction Need for effective interaction Aviation accidents: most have human error component

CRM Evolution Evolution of CRM to fifth-generation

CRM Training

Objectives of CRM

Knowledge, skills, attitudes to promote safe, efficient operations:

– Effective decision making– Good crew communication– Understanding/acceptance of role and responsibilities

CRM focuses broadly on training transportable teamwork skills

CRM Training

Types of CRM course

Foundation Course– Wide range of topics covered– Focus on discussion and video

Continuation Courses– In depth coverage of topic areas– Skills practice (low fidelity)

LOFT/MOST– Skills practice (high fidelity)– Crew-centred debrief

CRM Training

Topics in typical CRM courses– Human information processing– Personality and attitudes– Communications– Teamwork structures– Teamwork behaviours– Leadership style– Decision making– Stress management– Human error– Situation awareness– Automation on the flight deck– Fatigue and workload– Case studies & research findings– Be able to list the main topics

CRM Training

Leadership issues

Effects of captain’s attitudes

Authority Gradient

CRM Training

Communication– US ASRS: most accidents involved failure of information transfer– Low-error crews demonstrate different patterns of comms

Communication skills know them!– Inquiry– Advocacy– Listening– Conflict resolution– Critique– Feedback

Barriers to communication– Physical; word usage; interpersonal; mental– Cultural and language barriers– Subordination problems– ‘Power-distance’ barriers

CRM Training

Core teamwork behaviours

– Monitoring

– Feedback

– Backing up

CRM Training

Ad hoc teams– Frequently arise in airline ops– 73% of accidents occur on first day crew flying together

Situation awareness– Important topic in CRM– See lecture on SA!

CRM Training

CRM training resources– Self-study– Classroom awareness training– Modelling– Classroom skills training– Skills practice in simulators– Practice/coaching during flying

CRM Training

LOFT– Run in a high fidelity simulator– Realistic sortie/real time– Crew and facilitator ‘in role’– Few failures – Non-technical focus – Focus on choice dilemmas– Non jeopardy– Crew-centred debrief using video

CRM Training

CRM Issues– What is ‘best practice’?– Does it work? – Those needing most help from CRM most resistant to

change– May change attitudes but not behaviour– Needs management commitment– CRM skill fade occurs over time– Cultural issues should be considered

CRM Training

Error and Accidents(See Accident module)

The following may help you structure yourKnowledge of this topic – drawn from workof John Chappelow

Perception

Intention

Action

Task

Disruptive factors

Enabling factors

Predispositions

ENVIRONMENT

SYSTEM

OPERATOR

personalitytalent

fatiguealcoholoverarousalunderarousal

ergonomics

trainingbriefingsocial context

noiseheatcoldvibration

threattask demand

Be able to list/describe themain factors

Error type Disruptivefactors

Enablingfactors

Predisposingfactors

Perceptionerrors

Stressors Physical Trait

Visual illusion Physiological Ergonomics PersonalityDisorientation Noise Handling

characteristicsLack of talent

Undetected threat Time pressure System logic InexperienceMisinterpretation Operational

pressureExcess zeal

High task demand Lack of airmanship

Intention errors Low task demand Sensory limitationsRule violation Threat Cognitive

limitationsInappropriatemodel

Distraction Motor limitations

Action errors Organisational StateCognitive failure Training AlcoholSlow response Briefing FatiguePrecipitate response Administrative

supportHypoglycaemia

Disorganisedresponse

Social context Life stress

Mishandling Low moraleUnderarousalOverarousalSocial factors

Error type Disruptivefactors

Enablingfactors

Predisposingfactors

Perceptionerrors

Stressors Physical Trait

Visual illusion Physiological Ergonomics PersonalityDisorientation Noise Handling

characteristicsLack of talent

Undetected threat Time pressure System logic InexperienceMisinterpretation Operational

pressureExcess zeal

High task demand Lack of airmanship

Intention errors Low task demand Sensory limitationsRule violation Threat Cognitive

limitationsInappropriatemodel

Distraction Motor limitations

Action errors Organisational StateCognitive failure Training AlcoholSlow response Briefing FatiguePrecipitate response Administrative

supportHypoglycaemia

Disorganisedresponse

Social context Life stress

Mishandling Low moraleUnderarousalOverarousalSocial factors

Social context9%Social factors

11%

Personality21%

Cognitive failure17%

Disorganisedresponse 26%

Ergonomics

TrainingBriefingAdmin.support

~ 40%

Inexperience

23%

Summary: major factors

IntrovertedExtraverted

Stable

NeuroticAnxious Impulsive

You’ve seen this before...

Expanded data set

Major causal factors: Human factors

0 5 10 15 20 25 30 35

E rgonom ic s

Lac k of airm ans hip

P ers onality

S ens ory lim itations

S oc ial fac tors

Dis trac t ion

Overarous al

A dm inis trative s upport

High tas k dem and

Inex perienc e

Num be r of m isha ps

Expanded data set

Sensitivity: Human factors

-15 -10 -5 0 5 10 15

Social context

Sensory limitations

Supervision

Lack of airmanship

Briefing

Administrative support

Inexperience

High task demand

Distraction

Social factors

This graph showsbenefit of eliminatingthe factor, and costof an increase in itsseverity

Social factors areseen to be moreimportant when weconduct sensitivityanalysis: these problemsare soluble

Error: Examples of Possible Remedies know this

Administrative support• Organisational interventions

Inexperience• More (or improved) training

High task demand• Selection (e.g., some personality types cope better with high workload)• Training creates more ‘spare capacity’• The system can be modified to reduce workload (automation, better ergonomics etc)

Distraction• May be able to select individuals less prone to distraction

Social factors• Personnel selection• CRM training

Human Factors Integration and Human Centred Design Concepts

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