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Flying the Extra Mile - Part 1: 9S Methodology

02 March 2020
Many organizations who implement ISO Management systems or venture into AS9100 often struggle with implementing a robust root cause and corrective action process.

Introduction to 9S Methodology

There are a number of tools out there such as 5Whys and Fishbone Diagrams but the IAQG along with the aerospace community have devised a supporting standard to the AS91XX series of guidance documents to help organizations with the root cause and problem-solving process. It is called ARP9136 and although you cannot be certified to this standard (currently) it will support your management system controls. It would also help any organization whether you are certified or not or even have ISO 9001, there is nothing stopping you also implementing this standard.

The guidance document was created to provide a methodology for performing root cause analysis to resolve a significant or recurrent issue (e.g., quality, On-time delivery (OTD), process, documentation), and has used some well-known tools such as 7 Steps, Root Cause Corrective Action (RCCA), 8D.

ARP9136 is titled Root Cause Problem Solving (9S Methodology). It is called the 9S methodology for the simple fact that there are 9 process steps to take in order to complete an effective root cause and problem-solving process, similar to the theory behind 8D.

Process Steps

The process steps for the 9S methodology are:

  • Step 0 - start immediate containment actions

  • Step 1 - build the team

  • Step 2 - define the problem

  • Step 3 - complete and optimize containment actions

  • Step 4 - identify the root cause(s)

  • Step 5 - define and select permanent corrective actions

  • Step 6 - implement permanent corrective action and check the effectiveness

  • Step 7 - standardize and transfer the knowledge across business

  • Step 8 - recognize and close the team

Full implementation whenever an issue is identified may not be necessary as it can be time-consuming; it is designed to be used when the root cause is unknown or inconclusive and should be based on risk. 

Under each of the process steps there are 9 elements that should be considered:

  1. Objective(s) of the step

  2. Output(s) of the step

  3. What are the associated actions for this step

  4. Why this step is necessary and the potential risk if no action is taken

  5. When does the activity take place

  6. Who are the principle process performances and applicable stakeholders

  7. How to manage this process step so that it is effective, including providing some proposed tools to be used

  8. Communication aspects to take into consideration

  9. Specific items to be considered

Step 0: Immediate Containment

Immediate containment should not be a new concept to anyone but is sometimes misunderstood in its requirement. Some of the major aerospace manufacturers state that immediate containment should be performed every time no matter what. Others state that it should only be performed when there is risk of product escape or if there needs to be a recall.

The “objective” part of this step states:
“To mitigate the impact of the problem, to protect customer operations and the organization (i.e., stop the problem from getting worse), and verify that the situation does not deteriorate until the root cause and contributing causes are known.”

I won’t go into all of the elements of this step but the objective makes it pretty clear to understand. You need to ensure that the problem is not going to get worse, some people will refer to this step as “putting a plaster on it”, “stop the bleeding”.

You should remember to identify who internally and externally is impacted by this issue and inform those parties and in some cases the authorities might need to be contacted. Consider work in WIP or that has already been shipped, what is currently at suppliers etc.

There are lots of good tips within the guidance document on how to deal with the immediate containment that goes through the 9 elements.

Step 1: Build the Team

Objective: “To ensure that all process performers and applicable stakeholders and functions (e.g., organizations, department, suppliers, customers) that may have an influence on the corrective action process and associated investigation are on the team.”

This step might get confused with step 0 where you identify who is impacted but it is separate, just because you identify a party as being impacted does not mean that you involve them as part of the corrective action team.

Your team should represent different functions that may have an influence on the problem and are able and willing to assist in the associated investigation and problem-solving activities. This could involve your customer as they could have design authority over the product you have manufactured, you may need their input into whether the product should be recalled or if the issue is not detrimental to the functionality of the product itself.

Other members of the team are likely to be the persons who are dealing with that product day to day and aren’t necessarily management. The people who are touching the product every day are likely to know it better than anyone else and can be very effective at identifying the fixes and solutions. Don’t assume that managers are the best personnel for the closure of issues.

The guidance document itself has a great table that you can use to help identify the right people and they identify at least one person that meets each requirement:

  • Sees the problem

  • Suffers from the problem

  • In charge of solving the problem (problem owner)

  • Could help to solve the problem

  • Actor in the process; generates or contributes to the problem

  • Will help to select the solution

  • May be impacted or disturbed by the fixing of the problem

  • Others

Step 2: Define Problem

Objective: “To understand the significance, impact, and size of the problem (i.e., depth and breadth of current conditions) and ensure the situation (i.e., problem) is accurately defined and thoroughly understood by the team and applicable stakeholders.”

You need to spend some time with this area to fully appreciate the situation and think wider than the issue itself as it can be impacted by a number of areas such as operations, different products, materials, defects, and malfunctions. 

The tendency at this point is to identify the root cause but this should be avoided, you need to fully understand the problem before focusing on the whys and fixes. Take time to fully describe the current situation; how big is the problem, what is the impact (OTD, quality, cost, scrap, safety etc).

Step 3: Complete and Optimise Containment Actions

Objective: “To ensure containment actions suitably address the problem statement and to verify that immediate corrective action is commensurate with the problem, implemented, and effective.”

This should be the actions you take to stop the “bleeding” defined in Step 0. You should be checking that all nonconforming product or data has been isolated and corrected to prevent escape, and optimise immediate corrective actions to minimize impact on the customer, operation, and organization until the root cause of the problem is understood, permanent corrective action is taken, and their effectiveness is verified.

It may be that the fix you done in step 0 is sufficient but you should use this step to verify that and not just assume that what you done in step 0 was actually effective in stopping the bleeding. Maybe you need another plaster (or band aid if you are from USA).

Step 4: Identify root cause(s)

Objective: “To identify, through structured root cause analysis, the root cause for the undesirable condition, situation, nonconformity, or failure, including the reason it was not detected.”

This step is where some of your traditional root cause analysis tools come into play such as Fishbone, 5 whys, cause and effect, FMEA, Fault Tree Analysis, Root cause chain and design of experiments.

The tool of choice (or multiple tools) should be used to identify the root cause(s) of the problem, there is a risk that you jump to what appears obvious so ensure that you apply the tools fully as what may first seem like the root cause is, in fact, just part of it. You can also have multiple root causes, it doesn’t have to be just one root cause.

Make sure this is done as a team, time and time again I see people try to do root cause on their own but you can only see one side of a coin at any one time. You need to involve other team members who can see the other side of the coin!

Step 5: Define and Select Permanent Corrective Actions

Objective: “To define, prioritise, and select corrective actions that should be implemented to address the causes (root causes and contributing causes) and permanently prevent the undesirable condition, situation, nonconformity, or failure from recurring.”

This part catches out a lot of people when identifying corrective actions. The key here is to make sure the permanent corrective action addresses the root cause. I see a lot of times that organizations will either identify great root cause and not the corrective action to fix that root cause or they do it the other way around, identify great corrective action which doesn’t have anything to do with the root cause. One of the steps is wrong if they do not match.

The corrective action should always fix the root cause. To help with this concept, imagine having a gutter that is leaking in one area and water is pouring out, you wouldn’t replace the gutter on another part of the house!

You need to ensure that the problem doesn’t reoccur when identifying your actions. 

Step 6: Implement Permanent Corrective Action and Check Effectiveness

Objective: “To ensure all selected corrective actions are implemented (as defined), and to assess their effectiveness in preventing the undesirable condition from recurring and/or in detecting it sufficiently upstream in the process.”

Time and time again this element is not done correctly, often rushed and never reviewed. Organizations assume that the fix they identified has been implemented and has indeed worked and never verify it. We often see corrective actions not actually implemented or only partially implemented. You need to follow things up to check they have been implemented as planned.

The verification of effectiveness is also key. Many organizations will sign off their verification activity on the same day that the corrective action has been implemented. You cannot verify that it has been effective in addressing the issue until sometime in the future when the system has been tested again. Maybe this is the next time the product is manufactured? Never assume that what you said will solve the problem has indeed worked.

A little tip, if you are getting trends in your non-conformances then the chances are the corrective actions you have implemented have not been effective, if they were effective then you wouldn’t have the same issue happen again.

Step 7: Standardize and Transfer knowledge across the business

Objective: “To document analysis, results, and changes to capture and share learning with applicable stakeholders to prevent the similar undesirable conditions, situation, nonconformity, or failure occurring on other products, production lines, factories, or suppliers.”

Why keep solutions to yourself? It does not help anyone if you do not think about other parts of the business or products which may also be impacted by the issue. Think about other parts of the business that could be impacted, you want to stop the same issue from occurring in other areas.

Think of it like this. You may be painting a car and by the time the car gets to the end of the production line it’s started flaking, you go back to the painter and find out the paint is contaminated so quarantine the paint etc.  That same batch of paint might be used on another production line for another type of car, you should probably go and quarantine that paint also. Or maybe you have found a better way of painting the car which uses less paint or is quicker but you get the same quality. Why keep that secret to yourself, share the knowledge and then the other painting lines can implement the same technique.

Step 8: Recognize and Close the Team

Objective: “To ensure all team members and stakeholders are aware of the successful implementation of all corrective action, to confirm that the activity is closed, and to recognize and reward their work and accomplishment.”

This one should be self-explanatory. Too often action items are left open, diverting people from their primary roles. Furthermore, closed-loop corrective action is not achieved because there is no feedback or actions/results to applicable stakeholders and team efforts are not recognized, which negatively affects the dynamics of the RCCA culture. Lessons should be learned and shared, ensure the customer has been informed of the closure.


As you can see from the above, the steps are pretty clear and easy to follow, there is detailed information within the guidance document itself and there are some template forms that can help you with the implementation. You can, of course, come up with your own forms.

Root cause and problem-solving may seem like a long process and some will say it takes more time to fill the forms in that to fix the problem but if you count up all the times you have to fix the same problem compared to completing effective root cause and corrective actions once then its time well spent.

If you would like more information on this subject or to speak to a member of the NQA team you can email us here or call us on 0800 052 2424.

NQA also offer training on Aerospace, if you would like to get more information about this please click here.