"What gets measured gets done" is a statement often used when talking about the need for business key performance indicators (KPI).  Not only that, expressing KPIs in financial terms soon attracts attention.   If you know the cost impact of a problem then you can prioritise the necessary solution.


But what happens when you have a big problem that isn't quantified financially? Does it mean there's a lack of urgency to solve it? What if the cost impact is felt outside your department, or it is felt in another organisation entirely? Why should you do something about it if it isn't hurting your organisation?

These scenarios may sound far-fetched and unscrupulous and yet they feature regularly in the backdrop of maintenance No Fault Found problems. That's why in this blog article we wanted to tell you a bit about the financial size of the problem and what might be done about it. 

Where is the cost incurred? 

A No Fault Found scenario generally starts with an end user, such as a pilot, experiencing a fault symptom, and ends when the fault is correctly rectified (whether on the first attempt or a subsequent attempt).  This chain of events incurs operational costs (such as having to repeat a training sortie, or because of a delayed despatch), repair costs at line/shop/MRO/OEM maintenance levels (maintenance man-hours, replacement components and consumables, test equipment) and logistics costs (packing, handling, storage and transportation). If it takes several attempts before the fault is correctly repaired then each of these costs increases even more.  Every cost incurred - except those directly associated with the successful repair attempt - is avoidable.  But how much does it really cost?  Compiling NFF cost and KPI data has always been problematic, especially when the full picture often only becomes clear by evaluating data across complex structures, both organisationally  - from the flight line to MRO/OEMs – and commercially.  The picture is further complicated by the growing prevalence of ‘Power By the Hour’ and Performance-Based Logistics support contracts. 

A problem measured in $Billions

Whilst there are few published sources of comprehensive NFF cost data, significant examples can be found from across the aerospace industry and they are extremely indicative of the magnitude of the problem. 

  • In the early 1990s British Airways estimated the financial impact on their activities at £20M per year.  This was based on an average of 8000 component removals per month.  80% of all NFF occurrences involved avionics and these items constituted 27% of all avionics removals.
  • A few years later, in 1997, the US Air Transport Association estimated that NFF costs were running at $100,000 per aircraft per year.  Assuming that NFF rates have not gone down significantly in the commercial aviation sector since that figure was published, then the 2014 adjusted figure would be over $140,000 per aircraft per year - in other words a global cost of over $2.2B every year.
  • In recent years the US Air Force has taken steps to address high NFF rates on an avionics LRU from the F-16 radar system: the MLPRF (modular low power radio frequency).  It was calculated that the annual maintenance cost was $2M per year for this one component type."
  • The US Naval Air Command (NAVAIR) is reported to have spent $94M on NFF equipment removals which have actually resulted from wiring problems.
  • As for the wider US DoD, it has stated that their entire annual NFF cost exceeds $2B per year - a notable proportion of their $80B total annual maintenance bill.
Do you know your NFF cost?

If you know the value of how NFF impact on the life-cycle costs of your systems, equipment or aircraft then you are in the minority.  A No Fault Found survey was conducted by Copernicus Technology in 2012 with participants drawn from virtually every facet of aerospace flight and maintenance operations world wide, with respondents who filled roles from the Board Room to the Shop-Floor.  The main body of participants were from the EU and North America, especially from the UK and USA.  [An updated survey was conducted in Q1 2015 and the results since published.  If you would like a copy email This email address is being protected from spambots. You need JavaScript enabled to view it.]. 

  • 66% don’t know how much No Fault Found costs them
  • Only 34% of the survey respondents could quantify the cost of NFF on their business, broken down as follows:
  • 22% estimated their annual NFF cost at less than $1M
  • 8% said it was between $1M - $5M
  • 4% said it was greater than $10M per year

Delving deeper into the survey responses revealed further insights.  For example out of all the maintainers who had answered the question, 90% of them were not aware of the cost impact of NFF on their organisations, whereas the figure for ‘executives’ not aware of the cost impact was 67%.  North American respondents followed the overall trend but UK respondents scored worse, with 76% of them responding "don't know".

So what?

The figures highlighted in this article clearly illustrate that No Fault Found is a global maintenance problem costing billions every year.  That’s just in the aerospace sector.  The global mobile phone industry, for example, estimates the annual cost of NFF at $4.5B. Every year Automotive warranty problems amount to $12.3B world-wide - how much of that is accounted for by NFF occurrences?  What about the Rail sector? Oil & Gas?  The list goes on. Despite the prevalence of the NFF problem, step-change improvements are few and far between and so the lack of cost impact data means that dealing with the problem is unlikely to be escalated.  Because “what gets measured gets done”. So the message is clear, you need to count the cost in the context that is most relevant and useful to the pain points in your organisation – whether that is focused around mission success, operating costs or reputation. The alternative is ‘Do Nothing’ – which assumes that every year you can afford to keep throwing away vast sums in avoidable costs.

The UK's aerospace NFF Working Group is currently investigating this issue so please get in touch if you would like to be involved.  The Group is planning to compile best practice guidelines including how to calculate NFF cost impact.



[1]   Cockram J, Huby G. No Fault Found (NFF) occurrences and Intermittent Faults: improving availability of aerospace platforms.  CEAS 2009 Conference proceedings.

[2]   Khan S, Phillip P, Jennions I, Hockley C.  No Fault Found events in maintenance engineering Part 1: current trends, implications and organizational practices.  Reliability Engineering and System Safety 123 (2014) 183-195.

[3]   Huby, G. No Fault Found: aerospace survey results. Copernicus Technology Ltd, 2012. 

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