AS9102 Part Revision Change Levels

[LukeT]

I have a question that may seem confusing and that is because it is confusing. If anyone can decipher this and give me some input that would be great. Here is the situation.

Assembly A has a dash number of -004 and that is where the base documentation is at. Now we build this assembly at this level. As some point in time the assembly gets a revision change and instead of using the normal DRW rev. or BOM rev system of change the customer changes the assembly # to a different dash number say -005. Now the customer says that this change is the addition of the 52 jumper wires and 2 IC's, and it only is requiring a delta FAI to the -004 part. Keep in mind that while the -004, and the -005 both share the same PCB but the documentation for them is at their own level. Meaning if the -005 goes to a -985 it is the same assembly less coating or bond, etc, but the baseline documentation is at -005. Now if there was never a FAI performed at all at the -005 level and the board went to a -006 it is my opinion that it would need a FULL FAI at that level.

In my opinion this kind of change is a delta to the base line part number. If the change goes across two baseline part numbers then it should be a FULL FAI to create a baseline.

I know this sound crazy, but we are struggling here and I would like to see what if anything anyone can make out of this. Thanks

[Wes Bucey]

Originally Posted by LukeT

I have a question that may seem confusing and that is because it is confusing. If anyone can decipher this and give me some input that would be great. Here is the situation.

Assembly A has a dash number of -004 and that is where the base documentation is at. Now we build this assembly at this level. As some point in time the assembly gets a revision change and instead of using the normal DRW rev. or BOM rev system of change the customer changes the assembly # to a different dash number say -005. Now the customer says that this change is the addition of the 52 jumper wires and 2 IC's, and it only is requiring a delta FAI to the -004 part. Keep in mind that while the -004, and the -005 both share the same PCB but the documentation for them is at their own level. Meaning if the -005 goes to a -985 it is the same assembly less coating or bond, etc, but the baseline documentation is at -005. Now if there was never a FAI performed at all at the -005 level and the board went to a -006 it is my opinion that it would need a FULL FAI at that level.

In my opinion this kind of change is a delta to the base line part number. If the change goes across two baseline part numbers then it should be a FULL FAI to create a baseline.

I know this sound crazy, but we are struggling here and I would like to see what if anything anyone can make out of this. Thanks

Ultimately, the question boils down to what the customer requires and whether any government agency regulations apply to the situation.

If the product is custom made for only one customer, the customer's requirements prevail unless a government regulation supersedes (for an FAA-PMA part, as an example.)

When we use the term FAI, are we discussing dimensional inspection or functional inspection to use as a baseline?

In my aerospace years, the consequences in documentation, approval, reporting, and implementation of the change were different, depending if the change was "major" or "minor." A major change meant nothing could be implemented (used) on an aircraft until a complete investigation of the ramifications of that change had been investigated by organization engineers, customer engineers, and FAA engineers and approved by all. Depending on contractual agreements, minor changes could be implemented after the organization alone had investigated and approved the change and up to six months was allowed to "notify" FAA of the minor change.

The question of the difference between major and minor is the stuff of a different thread, but it seems to me we are not getting a sufficient background on why you feel the baseline needs to be reset with a new FAI for what appears to be a "minor" change.

[Jim Howe]

IMO Configuration Control dictates that if the change affects form, fit or function then a new part number must be issued. The change in dash # from -004 to -005 is a change in Part Number indicating that interchangeability has been affected. This is not a revision to the original -004 part but a brand new part. More simply the -004 can never be used for a -005. Since it is, by definition, a new part.

It has been my experience that, when this occurrs, a full FAI (First Article Inspection) is required. By changing the part number the customer seemingly is indicating that they recognize the above mentioned requirement but feel that a delta is all that is necessary. Its there risk!

That having been said we yield to what the customer decries, although I have been known to bring the oversight to the customers attention for confirmation.

[LukeT]

Thanks for your input guys, let me say this. It is a customer driven thing, and this is for both dimmensional and a functional change. The way I looked at it was that if the -004 will never be used because it is made obsolete by the -005 then the -005 should have a FULL FAI performed on it. I just thought that there shold be a clear line all the way back to the baseline part number which is the -005, or -004. The spawn of those baselines would be -984 or -985. I am probably looking too hard at it though, and I have been told that if that is what the customer wants then that is what they get. My only concern would be that we can be compliant to the customer requirements and still be non-compliant to the standard.

You spoke of the fit, form or function requirement. This is one area where the customer has enhanced the requirement by making it necessary to do a FAI whenever there is an ECO that up revs either the BOM rev or the assembly rev, regardless if it is clerical or mechanical.

I did speak to one person in quality from the customer and they agreed that it would be a FULL FAI, but I was ultimately over ruled because the sales side would be affected by this so in order to keep our OTD and forecast a DELTA was performed and submitted.

This is a thankless job sometimes.

I have contacted SAE to get some clarification on the standard, I will contact their representative on Friday. Thanks again fellas!!

[Wes Bucey]

I have often spouted off about the term and concept of "Configuration Management" which addresses (among other things) the point at which changes cease to be revisions and become new "things."

In my own practice, I like to draw the line at backward and forward compatibility. This is where the "management" part of configuration management comes in. If the new revision won't fit or function in the previous version's place or vice-versa, then it's time to create a new document or part number.

My experience with "dash numbers" (essentially variations of a standard part created as a "family" of parts) is that EACH dash number is treated as a separate part for manufacturing, testing, inventory, and usage. One family of parts I recall were housings for sensors. Each dash number was identical to every other dash number in every dimension but two - overall length of the part and depth of the internal cavity. The difference between a series of dash numbers was in increments of one-tenth of an inch. The difference was critical in terms of the fit of the sensor which fit in the cavity. The parts were NOT interchangeable. We had performed FAI on each dash number as if it were a completely separate part.

We struggled to keep the parts from mixing in handling prior to hand-stamping a dash number on each part. Finally, we "FMEA'd" and "Poka Yoked" to the point where we convinced the customer to let us add non-functional "identity" grooves to each dash number part, so they could be visually identified without recourse to micrometers.

The net result was zero mixing of parts, elimination of a hand-stamping procedure, and a lower net cost to the customer (the grooving process was done simultaneously with cut-off), although we made a higher profit per piece.

The point being you need to communicate with the customer every time a question arises and then you can negotiate the best course of action for all concerned. In some cases, this may result in a saving which will endear you to a customer, but, in every case, will result in "peace of mind" from knowing possible glitches have been avoided. In no instance should you undertake the expense of FAI on your own unless there is a question in your mind that there may be a problem. If the customer is content with a normal inspection procedure (not an in-depth FAI), so should you be content - unless there is something you know about the production process which could introduce a discrepancy in one of the dimensions in common with all the other dash numbers (in my example, this might have been a possible change in internal diameter of the cavity from using a different boring tool)

[mshell]

I have no experince with AS9102 so please tell me what form is used to submit a Delta FAI?

[Wes Bucey]

Originally Posted by mshell

I have no experince with AS9102 so please tell me what form is used to submit a Delta FAI?

By "delta fai" do you mean a first article inspection made after a "change" has been made in a product?

The key benefits from AS9102 will be that it clearly answers the larger questions revolving around the conduct of the FAI:

• WHEN - AS9102 (Sections 5.1 & 5.2) clearly and definitively specifies when an FAI, or a delta FAI, must be conducted.
• WHAT - AS9102 (Sections 5.1 & 5.6) describes what component of the end item must be included in the FAI and what inspections/verifications must be conducted on those components and their associated processes.
• HOW - AS9102 (Sections 5.7 through 6.7) specifies how the FAI must be documented.

I'm not sure if I know of a specific "form" where one fills in the blanks - anyone else?

[Jim Wynne]

Originally Posted by Wes Bucey

By "delta fai" do you mean a first article inspection made after a "change" has been made in a product?

I'm not sure if I know of a specific "form" where one fills in the blanks - anyone else?

From the capitalization of "Delta" I thought that perhaps the airline was being referred to, but I guess we'll have to wait for clarification from the OP.