23.603(b) Workmanship must be of a high standard. 1

As a design engineer I'd strike that requirement out. It is unmeasurable and hence useless.

Cheers

Greg Locock


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is "workmanship" referring to the production side of things ? This statement is a specific part of 23.603, ie 23.603(b).

this has fallen off the current 23.2260, which talks to materials and processes specifically.

Maybe the problem is that Part 25 (which doesn't have this requirement) works with approved manufacturing facilities, but Part 23 maybe doesn't (can't, didn't) assume that ?

Unfortunately Greg, we can't just strike it ... it's an airworthiness standard that needs to be found compliant.

You can probably get away with a "noted, and compliant" finding (depending on your delegate). Maybe you can flesh that out with "the manufacturing facility needs to be ISO 9001 qualified, or other equivalent manufacturing standard)."

This is for an STC, or an LSTC (or a Type Certificate) ? IF LSTC, then it's easier, you can use your facility's qualification.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

To save everyone the headache of looking it up...

23.603 said:

(a) The suitability and durability of materials used for parts, the failure of which could adversely affect safety, must--
(1) Be established by experience or tests;
(2) Meet approved specifications that ensure their having the strength and other properties assumed in the design data; and
(3) Take into account the effects of environmental conditions, such as temperature and humidity, expected in service.
(b) Workmanship must be of a high standard.

Click to expand...

25.603 said:

The suitability and durability of materials used for parts, the failure of which could adversely affect safety, must--
(a) Be established on the basis of experience or tests;
(b) Conform to approved specifications (such as industry or military specifications, or Technical Standard Orders) that ensure their having the strength and other properties assumed in the design data; and
(c) Take into account the effects of environmental conditions, such as temperature and humidity, expected in service.

Click to expand...

I've highlighted the part in question. Up until that funny line, the two read largely the same. The first statements can be targets of a particular design activity and/or manufacturing process control.

I think the FAA is just up against inertia and "what if" thinking. If they take out "high standard" then the tongue-waggers will go on about the FAA "no longer requiring high standards, harrumph". Nothing good can come out of giving them ammunition. The FAA is under enough attacks already. Anyway, they dumped the whole thing years ago with amendment 64, and only us after-market modifiers and STC holders need to care.

My advice, if you're writing something that is intended to "show compliance" then just tackle the first paragraphs with specific details that you can manage, and let that one just slide in along for the ride.

It's unquantifiable and unmeasurable thus not in-line with "best practices" for requirements.

Since it deals with tangible materials, if you need to show compliance the point to the production and inspection processes that you have in place to assure that material complies to its defined requirements.

23.603(b) probably goes back to early days of the regs when there were a lot of small companies/shops making small aircraft, and the FAA wanted some vague wording which they could cite when the didn’t think much of the workmanship of a plane fabricator.

that was my thinking. the current 23.2260 is much closer to 25.603 and drops 23.603b.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

I just refer to the governing approval of those manufacturing it and installing it
i.e. Workmanship is of a high standard as it is manufactured / installed by part 145 organisation.

verymadmac said:

I just refer to the governing approval of those manufacturing it and installing it
i.e. Workmanship is of a high standard as it is manufactured / installed by part 145 organisation.

Click to expand...

That can become a circular argument.

On the shop's Part 145 approval they can say "qualified to manufacture & install parts & repairs to Part 23 & 25 standards".

Now neither the shop nor the designer has said anything worthwhile.

NASA and DoD have a number of workmanship standards; they are prescriptive in nature, so demonstrable.

TTFN (ta ta for now)
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