![Advisera Mark Hammar](https://advisera.com/wp-content/uploads/blog_authors/markhammar.jpg)
November 23, 2017
When implementing your aerospace Quality Management System (QMS) you will very likely come across the concept of key characteristics in your customer requirements, even before you review the requirements of AS9100 Rev D. This concept, and the necessity to manage the key characteristics of a product, are deeply ingrained in the fabric of aerospace quality management; however, not everyone understands the terms and requirements well.
Here is a bit about what key characteristics are and what you need to do about them.
The term “key characteristics” shows up a lot in the terms and definitions of AS9100 Rev D, with most of these special terms relating in some way to key characteristics; so, what is a key characteristic? A key characteristic is a feature or attribute that, when it varies from the ideal, has a significant effect on the ability of your product to meet requirements, and also requires specific action to control variation. These key characteristics can then become critical items, leading to special requirements as per the definitions in AS9100 Rev D. So, how exactly do we determine key characteristics, then?
There are two criteria, as defined above, which must be met for a key characteristic:
If you answer yes to both of these questions, then you have a key characteristic to deal with. Below are the steps you need to take.
To find out more about the special aerospace definitions in AS9100 Rev D, see this article: Five special aerospace terms in AS9100 Rev D.
There are a few basic steps to take when dealing with variation management of key characteristics as defined throughout AS9100 Rev D:
Once these controls are in place, you then need to use them as part of your QMS processes, correcting any nonconformities and taking corrective action where necessary as you would with any other controls. These five steps ensure that you identify what controls need to be in place within your QMS processes, and then update your processes accordingly.
If you have key characteristics that have been identified by your customer, or during your design process, you may want to investigate a more detailed key characteristics management process. AS9103, Variation Management of Key Characteristics, is a supporting standard that gives a best practice for managing this activity. For more on the standards that support AS9100 Rev D, see this article:How Do AS9101, AS9102, & AS9103 Relate to AS9100 Rev D?
While your products and services may not include any key characteristics, many within the aerospace industry do. When this is the case, it is critical that these characteristics are identified, controlled, and monitored so that their variation does not affect the safety or performance of the product or service affected. So, if you do have a product or service with a key characteristic, think of this as one risk management activity that can benefit your ability to successfully provide the products and services that your customers need.
Read this free white paper: Clause-by-clause explanation of AS9100 Rev D to understand product requirements.