Resetting the-LRU-Replacement-Norm

© 2016 Copernicus Technology Ltd. All Rights Reserved. www.copernicustechnology.com

Resetting the LRU Replacement Norm



The LRU Replacement Norm

When tasked with repairing an Avionics fault the default assumption routinely made by repair technicians is that changing a Line Replaceable Unit (LRU) will fix the problem


Reported Fault

LRU is the Cause

LRU is not the Cause

LRU to be Replaced & Sent for Repair

LRU ‘Repair’

Fault Not Found

A Fault Found & Fixed

No Fault Found


Reported Fault

LRU is the Cause

LRU is not the Cause


LRU ‘Repair’

Fault Not Found


No Fault Found

We need to Reset the LRU Replacement Normto stop incorrect LRU

replacements


LRUs that keep going round this loop are

‘rogues’ or ‘bad actors’

Reported Fault

LRU is the Cause


LRU ‘Repair’

Fault Not Found



Why is this The Norm?§ ‘The book’ (FIM / TSM / AMM) says change

an LRU

§ ‘There’s one in stock & it’s a quick fix’

§ ‘When you replace the LRU it passes BITE so that’s it fixed’…and flying somewhere else

§ It’s what we’ve always done’

§ There’s limited maintenance history available for that LRU so it gets replaced anyway

§ Despatch rate is so important to reputation that all the LRUs mentioned in the TSM get replaced

§ ‘What are you supposed to do when the symptom has disappeared?

§ The diagnostic process doesn’t reproduce conditions as per when the symptom occurred

§ ‘We changed LRU X and the fault came back so this time we’re going to change LRU Y’

§ ‘We changed LRU X and the fault came back so this time we’re going to change LRU X’

§ ‘Suspect DOA’ or ‘Suspect U/S on fit’

§ ‘Other shift’…

§ ‘This wasn’t covered in training’

§ Lack of data on NFF / FNF / First-Time Fix rates etc

§ It takes 15 times longer to investigate the EWIS to see if it’s the cause


Why is this The Norm?

Fault Diagnosis

Policy

Culture

Technology

Training


A new LRU Replacement Norm is needed


LRU Replacement Norm

When tasked with repairing an Avionics fault the default assumption routinely made by repair technicians is that changing a Line Replaceable Unit (LRU) will fix the problem


LRU Replacement Norm

Replacing an LRU should be the last resortfor an Avionics repair unless faced with clear evidence to the contrary


Cont

ainm

ent

Mea

sure

men

t

Impr

ovem

entStrategy Approach


Cont

ainm

ent

Mea

sure

men

t

Impr

ovem

ent

NFF Maturity Model shortfalls

Manage rogue assets

Intermittent Fault Detection (IFD)/Integrity testing of EWIS and rogue LRUs

Modify LRU repair procedures v IFD results

Symptom Diagnostics: correlate symptom/fault/fix data to upgrade diagnostic procedures/training

Correlate Symptom Diagnostics data with LRU repair organisations

Embed new ways of working in Contracts

NFF Maturity Model

Identify ‘rogue’ ac/LRUs/SRUs

Correlate repeat arisings v LRU changes

Analyse Ship or Shelf data for quick wins in diagnostic procedures/training

NFF Reduction policy

Ship or Shelf

Notify repair organisations of repeat arisings v LRU changes

Strategy Approach

Copernicus Technology “No Fault Found” Maturity Model © 2015. Copernicus Technology Ltd. All Rights Reserved.

No Fault Found Maturity Model Unmanaged Developing Advanced Dynamic

Strategy

Policy No published policy Policy is published but not used or reviewed

Published policy is successfully used Published policy is successfully used and frequently reviewed/updated

Champion There is no NFF reduction ‘champion’ in the organisation

It is an implied role against a specific post

It is a secondary duty against a specified post but is not deemed a priority

NFF champion is empowered and proactive in implementation, KPIs & best practice

Contracts Contracts with repair bodies don’t include NFF reduction

NFF reduction is included but with no targets

NFF reduction is included with targets/KPIs

Contracts include gainshare opportunity from NFF reduction

Data Exploitation

Impact on Cost

Not recorded across the repair chain

Recorded in some parts of the repair chain but not used

Recorded in some parts of the repair chain and used occasionally/in isolation

Recorded and used proactively throughout the repair chain for evidence-based decision-making

Impact on Downtime

Not recorded across the repair chain Recorded in some parts of the repair

chain but not used Recorded in some parts of the repair chain and used occasionally/in isolation


Symptom & Repair

Not used to support fault diagnosis Used occasionally to inform fault diagnosis

Policy mandates use of Symptom & Repair data to inform fault diagnosis

Symptom & Repair data is codified, correlated & quantified automatically for fault diagnosis use

Fault Diagnosis

Training Does not cover NFF or ‘unable to reproduce symptom’ (UTRS) or intermittent fault scenarios

Anecdotally covers NFF/UTRS/ intermittent faults

Specifically includes NFF/UTRS/ intermittent fault strategies

Dedicated NFF/UTRS/intermittent fault training provided and regularly refined by Symptom & Repair data findings

Manuals Do not cover NFF/UTRS/ intermittent fault scenarios

NFF/UTRS/intermittent faults addressed by LRU replacement only

Provide greater latitude for root-cause analysis when diagnosing NFF/UTRS/intermittent fault problems

NFF/UTRS/intermittent fault content is regularly refined by Symptom & Repair data findings

LRUs All LRUs replaced during trouble-shooting are shipped for repair

LRUs replaced during trouble-shooting are occasionally held back pending repair-success confirmation

Policy enables quarantine of LRUs replaced during trouble-shooting pending repair-success confirmation

LRU-quarantine results vs repair-success data is used to optimise fault diagnosis training and manuals

Test Equipment

Rarely used due to lack of familiarity

Used occasionally in trouble-shooting but only as a last resort

Effectively deployed in trouble-shooting to detect ‘hard’ faults

Effectively deployed to successfully detect ‘hard’ and intermittent faults

Score per box: 1 2 3 4

Copernicus Technology “No Fault Found” Maturity Model © 2015. Copernicus Technology Ltd. All Rights Reserved.

Unmanaged Developing Advanced Dynamic

Strategy

Policy No published policy Policy is published but not used or reviewed Published policy is successfully used Published policy is successfully used

and frequently reviewed/updated

Champion There is no NFF reduction ‘champion’ in the organisation

It is an implied role against a specific post

It is a secondary duty against a specified post but is not deemed a priority

NFF champion is empowered and proactive in implementation, KPIs & best practice

Contracts Contracts with repair bodies don’t include NFF reduction

NFF reduction is included but with no targets

NFF reduction is included with targets/KPIs

Contracts include gainshare opportunity from NFF reduction

Data Exploitation

Impact on Cost

Not recorded across the repair chain

Recorded in some parts of the repair chain but not used

Recorded in some parts of the repair chain and used occasionally/in isolation


Impact on Downtime

Not recorded across the repair chain Recorded in some parts of the repair

chain but not used Recorded in some parts of the repair chain and used occasionally/in isolation


Symptom & Repair

Not used to support fault diagnosis Used occasionally to inform fault diagnosis

Policy mandates use of Symptom & Repair data to inform fault diagnosis

Symptom & Repair data is codified, correlated & quantified automatically for fault diagnosis use

Fault Diagnosis

Training Does not cover NFF or ‘unable to reproduce symptom’ (UTRS) or intermittent fault scenarios

Anecdotally covers NFF/UTRS/ intermittent fault

Specifically includes NFF/UTRS/ intermittent fault strategies

Dedicated NFF/UTRS/intermittent fault training provided and regularly refined by Symptom & Repair data findings

Manuals Do not cover NFF/UTRS/ intermittent fault scenarios

NFF/UTRS/intermittent faults addressed by LRU replacement only

Provide greater latitude for root-cause analysis when diagnosing NFF/UTRS/intermittent fault problems

NFF/UTRS/intermittent fault content is regularly refined by Symptom & Repair data findings

LRUs All LRUs replaced during trouble-shooting are shipped for repair

LRUs replaced during trouble-shooting are unofficially held back pending repair-success confirmation

Policy enables quarantine of LRUs replaced during trouble-shooting pending repair-success confirmation

LRU-quarantine results vs repair-success data is used to optimise fault diagnosis training and manuals

Test Equipment

Rarely used due to lack of familiarity

Used occasionally in trouble-shooting but only as a last resort

Effectively deployed in trouble-shooting to detect ‘hard’ faults

Effectively deployed to successfully detect ‘hard’ and intermittent faults

Score per box: 1 2 3 4

üü

ü

ü

ü

üü

üü

ü

ü

ü

ü

ü

ü

ü

ü ü

ü

In the above example the score is 28 / 100

Apply these scores, by column, to each completed box

10 12 6 0

No Fault Found Maturity Model

Scoring Method


Conclusions (1)The LRU Replacement Norm

Is a major driver of repeats arisings, NFFs & degraded readiness/availability/ dispatch performance

Is caused by policy, culture, training & technology factors

The NFF Maturity Model is the basis of resetting the Norm through:

• Containment

• Measurement

• Improvement


Conclusions (2)Essential areas to target:

• Data correlation at and between airframe and LRU maintenance levels

• Use of Symptom Diagnostics & Ship or Shelf data to optimise Fault Diagnosis procedures & training

• Managing ‘rogues’

• IFD testing of rogue systems’ EWIS and rogue LRUs


[email protected]

+44 (0)1343 842406

@CopernicusTech

www.copernicustechnology.com

Date post:	19-Jan-2017
Category:	Engineering
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Resetting the-LRU-Replacement-Norm

Engineering