Investigating no fault found in the aerospace industry

Reliability Engineering & System Safety

Phillips

Jennions

et al. 2014

This paper reviews the literature dealing with the nature and characteristics of no-fault found events within maintenance lines. Increasing systems complexities have seen a rise in the number of unknown faults that are being reported during operational service. Units tagged as 'No-Fault Found' are evidence that a serviceable component was removed, and attempts to troubleshoot the root cause have been unsuccessful. This scenario worsens when faults occurring at the component level are intermittent in nature. Here, the paper describes the prominent issues that have persisted across a variety of industrial applications and processes for decades. Some recent developments including standards, financial implications and safety concerns are highlighted.

Section: Fill In Technical Logbookmentioning

confidence: 99%

No Fault Found events in maintenance engineering Part 1: Current trends, implications and organizational practices

Reliability Engineering & System Safety

Phillips

Jennions

et al. 2014

“…However, the authors would like to emphasize that if there are no safety (or operational) related consequence of the failure, then corrective maintenance is probably the most effective maintenance approach to be adopted. The choice of an appropriate strategy for the failure management is guided by methodologies such as 'Reliability Centered Maintenance (RCM) 6 ' [42,43] for military aviation and other applications, or 'Maintenance Steering Group-3 (MSG-3) 7 ' [46] for civil aviation.…”

Section: Health and Usage Monitoringmentioning

confidence: 99%

“…The life-cycle environment of a product consists of manufacturing, storage, handling, operating and non-operating conditions, which may lead to physical/performance degradation 6 Reliability Centered Maintenance (RCM) is a structured approach to ensure that assets continue to do what their users require in their present operating context [40,41]. 7 Maintenance Steering Group-3 (MSG-3) based maintenance provides a top-down approach to determine the most applicable maintenance schedule, and the interval for an aircraft's major components and structure.…”

Section: Monitoring and Reasoning Of Failure Precursors Andmentioning

confidence: 99%

“…This paper aims to elaborate on these outlooks (from Part 1), whilst examining the technical aspects for complex systems and equipment (particularly products integrated within aircraft computer systems), and how such events can have a significant effect upon the overall unit removal rate. Historically, such removals have been seen as an unavoidable nuisance [5], but this viewpoint is no longer acceptable if the unit removal rate is to be managed effectively [6,7]. Unlike those failures that result in 'Confirmed Faulty' events, the designer may have no direct influence on those aspects of the system that determine the NFF failure rate, therefore a direct mitigating action during the design phase is likely to be more difficult 1 .…”

Section: Introductionmentioning

confidence: 99%

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No Fault Found events in maintenance engineering Part 2: Root causes, technical developments and future research

Reliability Engineering & System Safety

Phillips

Hockley

et al. 2014

This is the second half of a two paper series cover aspects of the NFF phenomenon, which is highly challenging and is becoming even more important due to increasing complexity and criticality of technical systems. Part 1 introduced the fundamental concept of unknown failures from an organizational, behavioral and cultural stand point. It also reported an industrial outlook to the problem, recent procedural standards, whilst discussing the financial implications and safety concerns. In this issue, the authors examine the technical aspects, reviewing the common causes of NFF failures in electronic, software and mechanical systems. This is followed by a survey on technological techniques actively being used to reduce the consequence of such instances. After discussing improvements in testability, the article identifies gaps in literature and points out the core areas that should be focused in the future. Special attention is paid to the recent trends on knowledge sharing and troubleshooting tools; with potential research on technical diagnosis being enumerated.

“…Components tagged as 'No Fault Found' (NFF) are evidence that a serviceable component was removed, and attempts to troubleshoot for any root causes have been unsuccessful [49]. In essence, the existence of the NFF phenomenon has had a definitive negative impact upon critical system stakeholder requirements, which at the top level, often includes systems safety, dependability and life-cycle costs [50]. For that reason, it is essential to prevent NFF events or (at the very least) reduce the impact they can inflict on the business operation.…”

Section: No Fault Foundmentioning

confidence: 99%

Autonomous Maintenance for Through-Life Engineering

Farnsworth

Bell

et al. 2014

Decision Engineering

This chapter looks at the overall theme of automating maintenance practices with a particular focus upon the application of robotics within this field. Covering the current state of the art in automating maintenance processes this chapter also looks at the current challenges to moving beyond simple inspection and diagnosis to the design and construction of fully automated platforms for undertaking maintenance. This includes methodologies for capturing and classifying maintenance task processes so that they can be automated in some way and how to link this task classification with some level of automation. The chapter ends with a discussion on how the design process can be adapted to aid automated maintenance, self-healing and no fault found applications.