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  • May 02, 19
  • FQA
  • 5614 views

What are Critical/Major/Minor defects?


For example: I want no more than 1.5% defective items in the whole order quantity, on average over several production runs with that supplier means the AQL is 1.5%.


In practice, three types of defects are distinguished. For most consumer goods, the limits are:

  • 0% for critical defects (totally unacceptable: a user might get harmed, or regulations are not respected).
  • 2.5% for major defects (these products would usually not be considered acceptable by the end user).
  • 4.0% for minor defects (there is some departure from specifications, but most users would not mind it).


These proportions vary in function of the product and its market. Components used in building an airplane are subject to much lower AQL limits.


Note that this tool is used mostly during final shipment inspections (when the products are ready to be shipped out), and sometimes during production (when the number of products is sufficient to have an idea of the batch's average quality).

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