AS9100 8.3.5.e Design and Development Outputs - Key Characteristics / Critical Items

[CanadianQA]

Hi All,

I have a question about Key Characteristics / Critical Items. How would these typically be identified on a drawing? A symbol of some sort? Any measurement within a specific tolerance (+/- 0.0005")?

Also, what constitutes Key Characteristics / Critical Items? I know how the terms are defined in the standard, however the way I'm understanding them, pretty much any dimension that would affect fit form or function would be considered key or critical.

Consider this example. A 4" X 4"x 4" square piece of 6061T6 aluminum with edges radiused to .125" on all corners, with a 1" hole drilled directly in the middle of the block for a bolt to go through. The part fits into a mating cavity and is retained by the bolt. All dimensions have a tolerance of +/- .005". Would all dimensions for this block be considered key / critical as any outside of the tolerance affect fit form or function? I appreciate any advice.

 

[Sidney Vianna]

Re: AS9100 8.3.5.e Design and Development Outputs - Key Characteristics / Critical It

I have a question about Key Characteristics / Critical Items. How would these typically be identified on a drawing? A symbol of some sort? Any measurement within a specific tolerance (+/- 0.0005")?

Most OEM's have their published way of documenting it. For example from this Boeing document:

Boeing KC

• Sidney Vianna
• Jun 17, 2018

Also, what constitutes Key Characteristics / Critical Items? I know how the terms are defined in the standard, however the way I'm understanding them, pretty much any dimension that would affect fit form or function would be considered key or critical.

Dimensions are just one of many parameters that could be deemed KC/CSI. Normally, when you have a dimension identified as KC, one must record the actual dimension, instead of just checking it is within tolerances because variation management is associated with the management of these critical items. The IAQG Supply Chain Management Handbook has material that might assist you and you should also familiarize yourself with the IAQG AS9103 document.

 

[CanadianQA]

Re: AS9100 8.3.5.e Design and Development Outputs - Key Characteristics / Critical It

Great, thanks so much Sidney! I'll have a read of the AS9103 and the Boeing document.