The Safety Analysis Methodology

EHEST Conference13 October 2008

Cascais, Portugal

The Safety Analysis Methodology 2

Contents

Introduction on Approach and Scope of the analysisAnalysis MethodologyExample

The Safety Analysis Methodology 3

General Process

Reviewoccurrences

Develop Safety Action Plans

Implement Safety Action Plans

Monitors

The Safety Analysis Methodology 4

General Process

Reviewoccurrences

Develop Safety Action Plans

Implement Safety Action Plans

MonitorsSafety Analysis Team

(this presentation)

The Safety Analysis Methodology 5

Maintain international compatibility

Reviewing accidents using a standard

method adapted by IHST from CAST (US

Commercial Aviation Safety Team)

Format allows comparison with data

from the US and other regions

Approach

The Safety Analysis Methodology 6

Scope of analysis

Based on a data driven approach

Focus on:

Accidents (definition ICAO Annex 13)

Date of occurrence year 2000 - 2005

State of occurrence located in Europe For this purpose Europe is defined as the EASA Member States

(27 EU + plus Iceland, Liechtenstein, Norway and Switzerland)

Only those accidents are being analysed where a final report from Accident Investigation Board is available

The Safety Analysis Methodology 7

Analysis Methodology

1. Collect general occurrence information from accident report

4. Produce Intervention Recommendations (IR)

3. Assign standard codes to factors Standard Problem Statements (SPS)

from IHST taxonomy and HFACS

2. Describe and analyse the accident Identify events (what happened)

and factors (why it happened) in free text

The Safety Analysis Methodology 8

Process manual and tool

The Safety Analysis Methodology 9

1. Collect general occurrence information

From accident reportsIncludes:

Occurrence Date and State of OccurrenceAircraft Registration and Aircraft TypeType of OperationAircraft Damage and Injury LevelPhase of FlightMeteorological ConditionsPilot and co-pilot flight experience Etc.

The Safety Analysis Methodology 10

Accidents are broken down into an event sequence

The method requires describing, in free text:

What happened (events and conditions)

Why these happened (factors)

The analysis uses the expertise and experience of the regional teams

2. Describe and analyse the accident

The Safety Analysis Methodology 11

Three models used to assign codes1. Standard Problem Statements from IHST taxonomyAnd additionally, for a more thorough description of human factors2. Human Factors Analysis and Classification System (HFACS) by Wiegmann and Shappell, US DoT, February 20013. HFACS Maintenance Extension by US Naval Aviation

3. Assign standard codes to factors

The Safety Analysis Methodology 12

Standard Problem Statements from IHST taxonomy

Over 400 codes in 14 different areas

3. Assign standard codes to factors

Ground duties Part/System Failure

Safety Management Mission Risk

Maintenance Post-crash survival

Infrastructure Data issues

Pilot judgment & actions Ground personnel

Communications Regulatory

Pilot Situation awareness Aircraft Design

The Safety Analysis Methodology 13

Example Standard Problem Statements

3. Assign standard codes to factors

The Safety Analysis Methodology 14

HFACS by Wiegmann and ShappellOver 170 codes in 4 main areas to code human factors in detail

3. Assign standard codes to factors

Organisational Influences

Unsafe Supervision

Preconditions for Unsafe Acts

Unsafe Acts

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3. Assign standard codes to factors

Unsafe Acts

Errors Violations

Routine violationsExceptional violations

Decision errorsSkill-Based errorsPerceptual errors

The Safety Analysis Methodology 16

3. Assign standard codes to factors

Preconditions

Environmental Factors

Condition of Individuals

Personnel Factors

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3. Assign standard codes to factors

Supervision

Failure to Correct Known Problem

Planned Inappropriate

Operations

Inadequate Supervision

Supervisory Violations

The Safety Analysis Methodology 18

3. Assign standard codes to factors

Organisational Influences

Resource Management

Organisational Climate

Organisational Process

The Safety Analysis Methodology 19

Example HFACS codes

3. Assign standard codes to factors

The Safety Analysis Methodology 20

3. Assign standard codes to factors

HFACS Maintenance Extension (HFACS ME)

The Safety Analysis Methodology 21

Analysis Methodology

1. Collect general occurrence information from accident report

4. Produce Intervention Recommendations (IR)

3. Assign standard codes to factors Standard Problem Statements (SPS)

from IHST taxonomy and HFACS

2. Describe and analyse the accident Identify events (what happened)

and factors (why it happened) in free text

The Safety Analysis Methodology 22

For every coded factor one or several Intervention Recommendations can be suggested

AIB recommendations are includedWill be used at a later stage by the implementation team to generate Safety Action Plans

4. Produce Intervention Recommendations

The Safety Analysis Methodology 23

Assessment of confidence in factors and recommendations

SPS/HFACS are scored between 0-4 on:

Validity: Quality and credibility of information

(documented evidence versus expert judgment)

Importance: Contribution to the accident

IR are scored between 0-4 on:

Ability: Capability of an IR to mitigate an event

Usage: Confidence that an IR will be utilised and

will perform as expected

Will be used at a later stage by EHSIT

The Safety Analysis Methodology 24

Occurrence categories

Used to classify occurrences at a high level to permit analysis of the data in support of safety initiatives

Future developments based on existing internationally agreed taxonomy

Example:Share of Occurrence Categories (Top 7) in Accident Data Set

0 5 10 15 20 25 30 35 40

External Load

System/Component Failure - Powerplant

System/Component Failure - Non Powerplant

Controlled Flight into Terrain

Low Altitude Operations

Collisions during T/O and landing

Loss of Control - In Flight

Oc

cu

rre

nc

e C

ate

go

rie

s

Percentage %

The Safety Analysis Methodology 25

Analysis Example

The Safety Analysis Methodology 26

Thank you for your attention

Questions?

European Helicopter Safety Team

EHEST

The Safety Analysis Methodology 27

ANNEXEHSAT Analysis Tool

The Safety Analysis Methodology 28

Process manual and tool

The Safety Analysis Methodology 29

HFACS SPS taxonomy

Human Factors Analysis and Classification System (HFACS) D.A. Wiegmann and S.A. Shappell

Process manual and tool