AS9100-Sampling plan implementation

Lunas

Registered
Hello everyone,

I recently joined an aerospace start-up company, and we're in the process of drafting our procedures. Currently, we're in the prototype phase and don't yet have real customers until we launch our first rocket. Therefore, we're performing 100% quality checks for the items/parts produced internally.

As we begin drafting, I find myself with several unanswered questions:

  • What sampling plan is typically used as a reference in aerospace companies?
  • Are we permitted to implement a sampling plan for small quantities produced? The production team is negotiating the possibility of implementing a sampling plan whenever we need to produce more than 10 parts. They prefer not to conduct a 100% inspection. However, in the standards, the terms "batch" and "lot" are frequently used, which isn't applicable to our current situation, as we're producing parts/items dedicated to one rocket (one project).
I've attempted to find detailed information in forums but haven't been able to grasp it from previous discussions. Could you please share the necessary references and clarify if a sampling plan is applicable for small-scale production? If not, where can I find this information?

Thank you.
 

Mike S.

Happy to be Alive
Trusted Information Resource
Sampling is all about risk. A sampling program needs to be selected by someone who understands the specific risks involved.
 

Bev D

Heretical Statistician
Leader
Super Moderator
...And by someone who actually understands the statistical risks as well.
Remember the AQL means the ACCEPTABLE defect rate that will be accepted 95% of the time.
 

Kronos147

Trusted Information Resource
  • What sampling plan is typically used as a reference in aerospace companies?
Read the supplier quality manual from your customer. It should state their expectations.

Know that there is also a specification, AS13002 Requirements for Developing and Qualifying an Alternate Inspection Frequency Plans that is being pushed by some of the customer base. It may be beneficial to work those requirements into whatever plan you develop.

AS13002: Requirements for Developing and Qualifying Alternate Inspection Frequency Plans - SAE International
 

Mike S.

Happy to be Alive
Trusted Information Resource
What is a "small lot size" in your world?

How sure do you want to be that there are no defects?

Sampling does not work well at detecting small defect levels. For example:

If you want to be 95% sure there are no more than 5% defects in a lot, you need to inspect 60 random samples and find 0 defects.
 

Lunas

Registered
Read the supplier quality manual from your customer. It should state their expectations.

Know that there is also a specification, AS13002 Requirements for Developing and Qualifying an Alternate Inspection Frequency Plans that is being pushed by some of the customer base. It may be beneficial to work those requirements into whatever plan you develop.
Morning
Thank you for your answer
Actually we don´t have any customers yet since we´re still on prototype phases, final rocket planned to be launched are indeed to receive customers
Thanks for the shared document as well :)
 

Lunas

Registered
What is a "small lot size" in your world?

How sure do you want to be that there are no defects?

Sampling does not work well at detecting small defect levels. For example:

If you want to be 95% sure there are no more than 5% defects in a lot, you need to inspect 60 random samples and find 0 defects.
we are not having lot, the maximum quantity produced for one part is 20, which is directly used..
 

Bev D

Heretical Statistician
Leader
Super Moderator
With your small ‘lot’ numbers probably only for trivial characteristics.
You really need to understand the limitations of sampling and how it really works, before you can ‘trust’ it.
Most sampling plans have fairly large allowable defect rates with sample sizes that would not be 100% inspection for your situation. Please read “The Truth about acceptance sampling part 1 and part 2 by Donald Wheeler.
 
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