Zemel 18th S6 P3

Managing Aircraft Stuctural Integrity

in the ADF



WGCDR David Zemel

Deputy Director – Aircraft Structural Integrity





Aircraft Airworthiness and Sustainment

Conference 2010





1

Introduction

 Achieving ASI

• A little history

• The ASI Program

 Managing ASI in the ADF

• Development of the ADF ASI Program

• Contemporary ADF ASI Environment

• Current ADF ASI Policy

• ADF ASI Program Requirements

• Tailoring and ASI Program

• Example Through Life Support Arrangement





2

Aircraft Structural Integrity - History



“The property of an airframe to withstand the

loads for which it is designed”1









Reliance on Factor on Safety – accounted for

1USAF variability in:

Dictionary 1956 • loads

Cited in Report 680.1B, History of the Aircraft Structural Integrity Program, ASIAC, 1980

• structural analysis

• material properties

• deterioration over service life

• build quality





3

Aircraft Structural Integrity - History

Civil and Military structural failures in the 1950’s





Boeing B-47









De Havilland Comet







4

Subsequent developments in design development and in-

service management against fatigue

• Higher static strength leading to corresponding

increases in fatigue strength

• Fail-Safe design principles Seminal Accidents

Comet

• Damage Tolerance design principles

B-47

• Durability considerations F-111

B707

• Full Scale Fatigue Testing B737

• Ageing aircraft considerations

• Widespread Fatigue Damage considerations

• Corrosion control

• Dedicated ASI Programs…

5

Typical Civil & Military ASI Programs

Civil

• ICAO Airworthiness Manual

- Certification

- Continuing Airworthiness

- Continuing Airworthiness Assurance

• FAA Reg (25.1529 Continuing Airworthiness)

- Airworthiness Limitations

- Structural Inspection Requirements

- Mandatory Replacement Times



Military

• MIL-STANDARD-1530 (Parts)

- Design Information

- Analysis

- Full Scale Testing

- Fleet Data (and Certification)

- Fleet Management







6

Development of the ADF ASI Program

• 1980’s RAAF separated ASI management

- fatigue management (centralised),

- other forms of degradation (decentralised)

• No holistic whole of life management

• ASIP concept considered but never developed

• Debate over decentralising fatigue

management

• 1990 two unrelated accidents due to fatigue…







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Development of the ADF ASI Program

Nomad and Macchi

accidents - 1990

• Lack of appreciation of loads

• No fatigue test

• Used aircraft

• Use of condition data









• Control build quality

• No pertinent fatigue tests

• Algorithms in error

• Inadequate engineering

management system



8

Development of the ADF ASI Program

CAA Review of ASI in

ADF - 1992





 Findings

• RAAF had not identified the intended outcome from ASI

management

• Management system was not

- constraining risk

- providing timely germane advice to decision makers

• Processes in place, but outcome degraded due lack of

understanding of principles

• Dispersal of expertise should be avoided



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Development of the ADF ASI Program

 ADF’s first ASIP required:

 Assessing design against RAAF Standard

 Assuring quality on production

 Identifying critical items for through-life management

 Regular re-assessment of certification, management policy

(inspections), physical condition

 Collection and analysis of environmental & usage data

 Documentation of Program in a plan

 ASIP covered State aircraft only

 Based on ASI-DGTA performing a majority of the

ASIP tasks on behalf of WSLMS/SPO



10

Contemporary ADF ASI Environment

By mid 2000’s the landscape was changing:

• Through Life Support (TLS) outsourced to industry from acquisition

• Breadth of Airworthiness Management System

- State Registered (Mil Spec, Civil variant (EASA, FAR23, FAR25))

- Non-State Registered (VH reg)

- Increasing types due to capability expansion

- Increasing range of TLS models and certification standards

• Technology advancement

- Materials – e.g. composites, glare

- Standards – development and interpretation of ADF unique solutions

- Methods – e.g. RRA, SPD, FSW

- Structural Health Monitoring

- Non-destructive Testing

• Ageing fleets

- Broad range of logistic issues

- Effectiveness and applicability of the Certification Standard



11

Current ADF ASI Policy

 Recent changes to Policy - Further reflection on CAA

Review coupled with contemporary environment

 No longer use a comparative standard

 Less prescriptive. Pushes some of the prescriptive elements

into the Technical Airworthiness Management Manual

 ASIP Policy implementation becomes more flexible and responsive



 Define and specify ASI Program requirements

 Identifies contemporary roles and responsibilities

 Ability to use appropriate tailoring

 Requirement for retention of indigenous ASI knowledge

 ASI Program Guidance based on MIL-HDBK-1530

12

Current ADF ASI Policy Statement





Defence must have a program to manage

ASI and ESI for each ADF managed

aircraft supported by competent

organisations with appropriate levels of

knowledge and expertise









13

Current ADF ASI Policy Objectives

• Constraint of the risk of structural failure of an

aircraft to an acceptable level (Required Safety)

• Achievement of planned rates of aircraft

availability (Maximise Availability)

• Avoidance of unforecast cost of refurbishment

(Minimise Cost)

• Achievement of the planned withdrawal date

(Assure Capability)

• Continually Optimise the Program to minimise

cost and downtime

14

Flow of Requirements from ADF ASI Policy



Why Policy

Establishes

Implied

Directs Reqt

Reqt

What 053



How 054 ASIP

Reqt

Guidance Implements and

Executes Reqt

053 – Tech Airworthiness Management Manual

054 – ADF Design Requirements Manual ICA

ICA – Instructions for Continuing Airworthiness







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ASI Program Requirements



Cert Basis Build Quality





Data Reqt





ASI Program

SI Mgt Policy (ICA)

Documentation









Monitoring and

Assessment OLM



SLA AASA







16

ASI Program Information Flow

 Implementing the ASIP

involves establishing systems

that:

 Collect the data

 Assess the data

 Report on the outcomes

 Report types include

 Routine Usage Status

 Usage Assessment

 Fatigue Assessment

 Structural Condition Assessment



 These systems will be

described and approved in the

Management Plan. Specific

instructions will be required by The heart of a

the implementing authority – mature ASIP

SPO, TLS Contractor

17

Tailoring an ASI Program

 Ultimately any ASIP can be tailored

 Recognises the broad range of TLS arrangements

 Recognises different acquisition strategies

 Recognises legacy programs (Civil and Military)

 Recognises nature of configuration, role and operating environment

 Recognises broader application of Airworthiness Management System



 There are two main areas to be considered when tailoring

 Tailoring the ASIP requirements

 Tailoring the ASI management

 Tailoring ASIP requirements

 Default is full ASIP requirements

 Minimum requires some method to ensure System of Maintenance remains valid while

operating with ADF







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Tailoring an ASI Program

 Tailoring ASI management

 Defining the roles and responsibilities

 Account for nature of TLS arrangement

 Account for experience of implementing agency

 Account for role of aircraft

 All programs are to be Authorised by DGTA-ADF

 All programs are to have a manager assigned whose responsibility is to

ensure all elements of the ASIP are implemented.









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Tailoring ASIP Management

 Examples of TLS arrangements

 In-service Model (ASI/SPO)

 Outsource Model (ASI/SPO/Prime Contractor)

 Many variations

Example

 FMS Model (ASI/SPO/USAF)

 Lease Model (ASI/Contracting Agency/Contractor/NAA)

 Museum (ASI/Operating Org/NAA)









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Tailoring an ASI Program – Example TLS

ASI Program for One Aircraft Type

Supporting Activities

by ASI-DGTA

TLS Contractor ASI-DGTA

•Four Circles •Acquisition Support • Develop Policy,

•Implement SBI •Establish ASIP Reqts Procedures and

•ASIMP Input •ASIMP Approval Guidance

•SLA Conduct •ICA Approval SBI

•AASA Conduct •Manage Testing • Advice to Cap Mgr

•(ASI Management) Programs

•(ASIP Management) • Independent in-

service advice

SPO

•DAR • Education

OEM •Configuration Item Mgr DSTO

•Contracting • Interpret Standards

•Audit the AEO

SQN/ •Finance Industry • Audit Systems

WG







21

Summary ASI Management in ADF

 Driving Principles

 Safety

 Availability

 Cost of Ownership



 Management Principles

 Legacy certification (where possible)

 Understand Standards and their application

 Data collection, assessment and feedback

 Four circles - Primary

 Attestation against SoM - Secondary



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References

1. The History of the Aircraft Structural Integrity Program, ASIAC, Report No. 680.1B, 1980

2. Milestone Case Histories in Aircraft Structural Integrity, R. Wanhill, NLR, 2002

3. Investigation into Ansett Australia maintenance safety deficiencies and the control of continuing airworthiness of

Class A aircraft, File No. BS/20010005, ATSB

4. A Report into the Management of Aircraft Structural Integrity in the RAAF, CAA, 1992

5. Developments in RAAF Aircraft Structural Integrity, E.S. Wilson, RAAF, 1995

6. Some observations on fatigue life management, A.J. Emmerson, CASA

7. Aircraft and Engine Structural Integrity Management (Draft), DI(G) LOG 4-5-016

8. Code of Federal Regulations 14, Aeronautics and Space, FAA, DOT, 2010









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Questions?









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