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Human Factors Course

Session 1

Eric DaveyCrew Systems Solutions

2007 March 28

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NASA POES Spacecraft - Anomaly

Incident 1

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NASA POES Spacecraft - Anomaly

Incident 1

4

Accident Findings

Causal Factors Procedural Compliance

Sept 04 - Crew 1 - Bolt removal without documentation Sept 06 - Crew 2 - Cart use without verifying configuration

Consequences Launch delay ~ 2 years Significant rework and retest

Incident 1

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Other Possible Accident Factors

Design Spacecraft configuration - Tall Workplace - Service or transport Tools - Bolt visibility and interlocks

Operations and Organizational Independent verification Tag-out on configuration changes Shift change or work resumption practice Time - Saturday following supper Staffing - Numbers and experience

Incident 1

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American Airlines Flight 587

Incident 2001 November Airbus 300-600 departing New York for Puerto Rico Encounters wake turbulence on takeoff Tail/rudder failure and separation Loss of control

Consequence 265 lives lost

Incident 2

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American Airlines Flight 587

Headline Chronology 2002 Feb

CBS Dangerous Rudder Movements

2004 Oct BBC Queens crash blamed on co-pilot Globe Pilot error blamed in US Airbus crash CNN NTSB: Copilot error caused 2001

crash

Incident 2

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American Airlines Flight 587

Causal Factors Environment Departure scheduling - turbulence

Uncertainty in turbulence location Climb-out - High airspeed and airframe

load Training Response to wake turbulence

Roll recovery with aggressive rudder use Design Rudder sensitivity - full deflection

A300-600 32 lb and 1.2 in travel

Other Planes 125 lb and 4.0 in travel

Communication Breakdown between designer & airline

Incident 2

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Patient Hospital Safety - Canada

Adverse Event Study - 2000 AE - Unintended patient injury by medical system

Impact Incidence(Per 100 Admissions)

Adverse Event

Incidence(People/Year)

Preventable AE

AE - Death

Preventable AE - Death

7.5

2.8

1.5

0.66

185,000

70,000

37,000

16,000

Incident 3

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Patient Hospital Safety - Canada

Types of Complications Wrong medication or dosage 1 in 9 Infection Adverse drug reaction Hospital acquired injury

Consequences 1.1 million added days in hospital/year ~$750 million

Patient and family inconvenience Lost work time

Incident 3

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Problems with Medication Abbreviations

Common Misinterpretations

Abbreviation Meaning

µg

Misinterpretation

microgram mg - milligram

qn nightly qh - hourly

q1d daily q.i.d. - four times daily

HS half strength hs - bedtime

IJ injection IV - intravenous

Incident 3

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About this Course

Subject Application of human factors criteria and methods in design

to support users to achieve effective and error free performance

Context Facility design, training & operations

Outcomes Operational effectiveness Safety

Introduction

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Course Structure

Four Sessions Issues with human-systems operation

Break

Understanding human capabilities and performance

Lunch

Designing to support human-system interaction

Break

Applying human factors - Group exercise

Introduction

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Eric Davey

Education Electrical Engineering - Toronto & New Brunswick

Experience Applied Nuclear R/D - Instrumentation & Systems - 15 years - AECL

Chalk River Power Reactor Control Rooms & Operations - 15 years

Projects - Human Factors Task characterization and analysis Workspace design Systems development - Annunciation and Displays Operations assessment - Changes Regulatory compliance

Introduction

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Session 1 - Issues with human-systems operation

Topics Incident examples Course purpose & content Supporting human performance

Symptoms of problems Range of factors Approaches

What is human factors? Examples of assessing/providing task support

Introduction

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Symptoms - Lack of Support

User’s View What is it doing now?

Why did it do that?

How did I get into this state?

How do I stop it from doing this?

How do I get it to do what I want?

It usually works - what's changed?

Background

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Symptoms - Lack of Support

Trainer's View System takes too much time to

train

We don't train for every situation

We don't train on all features

System uses non standard conventions

Hopefully they will learn it on the job

Background

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Symptoms - Lack of Support

Designer's View System performed as designed

System design met requirements

System was not designed for that operating condition

System works okay, some don’t understand it

Background

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Symptoms - Lack of Support

Facility Impact Workarounds

Work delays & inefficiencies

Unrealized production

Events Disruptions in production Safety challenges

Background

Difficulties in Productioncan be precursors to

Safety challenges

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Why Human Performance is of Concern?

Responsibility People design, direct and supervise operation

Human Impact Pervasiveness of human involvement

Fallibility Human behaviour is not fail proof

Experience Human behaviour is a major contributing factor to

Safety challenges Production disruption & inefficiency

Background

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What Could Be Mismatched or Missing?

Support for Desired Performance

Background

PhysicalDesign

OperationalEnvironment

Person

DesiredPerformance • Task

• Supervision• Procedures• Practices• Culture

• Education• Job training• Experience• Fitness

• Workspace• Automation• Feedback• Reliability

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What Could Be Mismatched or Missing?

Support for Desired Performance

Background

• Location• Size• Colour

Political

Organization

Team

Cognitive

Physical

DesiredPerformance

• Info content• Info structure• Info relations

• Communication• Authority• Roles

• Policy • Law• Regulations

• Culture• Priorities• Resourcing

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A Model of Facility Operation

Background

Agents

Actions

Goals

Functions

Needs

WorkingTogether

Well

People Systems

Automation• Control• Monitoring• Detection• Respond to user

Tasks• Configuration• Supervision• Intervention• Servicing

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How Might Problems Occur? - Design

Background

Goals

Functions

Training(People)

Design(Systems & Automation)

Procedures(Tasks)

Step 1

Step 2

Step 3

Design for Accessibility• Design without task or user description

WorkingTogetherLess Well

Procedureand peoplecompensation

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How Might Problems Occur? - Operations

Background

Goals

Functions

PeopleSystems

& Automation

Procedures(Tasks)

WorkingTogetherLess Well

Equipment aging

Modified goals

Changes

Environmentalchange

Additional tasks

New functionality

Skill loss

Stress

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How Might Problems be Reduced?

Background

Goals

Functions

Training(People)

Design(Systems & Automation)

Procedures

Step 1

Step 2

Step 3

Design for Use• Design with task and user description

Step 0

Control Usage• Limit changes and monitor impacts

TaskDescription

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What is Human Factors?

Knowledge About the capabilities of humans and their interaction with

technical systems

Criteria and Methods For designing systems and workspaces so that user task

needs and operational objectives are successfully met.

Definition & Examples

So consistency in performance excellence can be achieved.

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Example - Audible Communication

Understanding Speech - Background Noise

Normal speech levels (1m) = 55 to 75 dB

Context

Design Criteria

Speech vs Background ConditionUnderstanding

Concentrated listening

Concentrated listening

Full

Full

Partial

> 5 dB

0 dB

< 5 dB

None

Definition & Examples

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Example - Visual Communication

Reading at a Distance

Definition & Examples

HeightSpacing

LuminanceContrast ratio

Factors

Design Criteria

Legibility

Distance = 2.5 m

Character Height minutes - arc cm

1.06

1.66

5

14

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Character - Minimum

Words - Minimum

Words - Preferred

0.38

A A A

A A A

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Exercise - Alarm Display Legibility

Situation Addition of alarm number to existing alarm display Design solution

Reduce character spacing to accommodate addition of alarm number

Questions Impacts on:

Viewing distance - Legibility User behaviours Task performance

Definition & Examples

C A R CAR

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Exercise - Alarm Display Legibility

Characterizing Impact Measure viewing distance

5x with old display 5x with new display

Calculate average viewing distance Repeat for 4 subjects Determine impact of display change

Definition & Examples

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Results Discussion Viewing distance impact

Other influencing factors Room illumination Text colour Subject visual acuity Subject familiarity with alarm messages

Exercise - Display Legibility

Definition & Examples

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Example - Display Design

Developing & Maintaining Plant Awareness

Current & PastPlant State

Expected Plant State

Definition & Examples

• Perception• Comprehension• Projection

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Understanding Monitoring Behaviour

Context Stable operation Variability in practice

Questions Objectives Strategies Parameters Representations Relationships

QuickTime™ and aPhoto - JPEG decompressor

are needed to see this picture.

Definition & Examples

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Monitoring Objectives

Periodic examination of current plant state to:

• Detect a change from normal in key indications

• Confirm goals selected are being achieved

Definition & Examples

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Operating Goals

Safety and Production Performance Health

DesignBasis

Licensed Operating

Range

Target Setpoint

Current Operating

Point

*

OperatingRange

Definition & Examples

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A Monitoring Strategy - Automation Functions

Heat Transport Pressure/Level

ReactorPower

BoilerLevel

Boiler Pressure

ElectricityGeneration

DeaeratorPressure/Level

OperatorSetpoint

Definition & Examples

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Types of Information Control Program Information

Process Setpoint

Disturbances

ProcessOutput

Continuous Feedback

Function

InternalPerformance Measures

• Performance• Health

Indication

Periodic Feedback

Adjustment

Definition & Examples

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Information Form

13:44:19 100.0

Representations which support: Value comparisons Parameter trending with time

101

98.4

95

PSA

RP SETPOINT%FP

PLIN

LIN N%FP

101

98.6

95

Trend Current Value

• Relationships

Bar Chart

96.0

Definition & Examples

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Enhancements to Existing Displays

Trend Display - Reactor Power

PLIN

LIN N%FP

101

98.5

95

80.0

44.19

20.0

101

98.4

95

+1.0

0.01

-1.0

PERR

RP ERROR%FP

PSA

RP SETPOINT%FP

LEVAV

AVERAGE ZONELEVEL %FP

• Process Outputs

• Process Setpoint

• Internal Measure

Organization

RangeAdjustments

Parameter Substitutions

Definition & Examples

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Example - New Display Concepts

Heat Sink Monitoring - Outages

Fuel Decay Heat Heat Transport Circulated Cooling Service Water

Shutdown Days

Pow

er (

MW

)

Pow

er (

MW

)

Pow

er (

MW

)

Pow

er (

MW

)

Expected Decay Heat

Actual Heat Produced

Heat RemovedFirst Heat Sink

Heat RemovedSecond Heat Sink

• Heat Sink• Flow• Inventory

• Heat Sink• Flow• Inventory

• Heat Sink• Flow• Inventory

• Time Zero

Reactor Delta T Heat Sink Delta T Heat Sink Delta T

** * *

Definition & Examples