What it is
STANAG 3347 is the NATO Standardization Agreement covering identification of aircraft electrical circuits. This is Edition 7, promulgated 22 September 2022, superseding "STANAG 3347 AE, Edition 6, dated 12 November 2014".
A STANAG is not the specification
A STANAG is the agreement by which NATO nations commit to implement a standard, not the technical specification itself. Most STANAGs point to an Allied Publication written for the purpose, but this one points straight to a civil aerospace standard: participating nations "agree to implement the following standard", named as "SAE AS50881 WIRING, AEROSPACE VEHICLE". That document is obtained from SAE on its own terms, not from NATO, and it is where the actual wire identification scheme lives, in its appendix B.
What it commits nations to
The stated aim is "to establish a common electrical circuit identification standard" that meets an interoperability requirement. What STANAG 3347 itself adds on top of SAE AS50881 is narrow: the circuit identifier is "part of the significant wire identification as detailed in SAE AS50881 appendix B", and that "significant wire identification shall be marked in accordance with SAE AS50881 requirements". The document names no other related documents of its own.
Who it binds, and how
STANAG 3347 binds nations, not suppliers. It addresses "the participating nations and NATO bodies", and it becomes binding on a given nation through ratification, which NATO records in the NATO Standardization Document Database (NSDD). Implementation is a separate, further step: the STANAG "is considered implemented when the provisions specified therein have been included in the national documentation related to the identification of aircraft electrical circuits". Once implemented, "Allies and NATO bodies shall provide implementation details through the electronic reporting tool (e-Reporting)". A supplier meets STANAG 3347, or the SAE AS50881 requirements it points to, only where a nation's requirements or a contract built on them say so.
How it's evaluated
STANAG 3347 describes no certification, audit, or inspection scheme of its own, and the document never uses the word "certified". What it describes is nations reporting their ratification and implementation status to NATO; national responses "are recorded in the NATO Standardization Document Database (NSDD)". Where a supplier's wire marking work against SAE AS50881 is actually checked, drawings, marking samples, inspection records, the assessor and the evidence required are set by the contract's own quality clause, not by this STANAG.
Standards it references
STANAG 3347 covers SAE AS50881, the civil aerospace standard that carries the actual significant wire identification and marking requirements in its appendix B. Reviews of STANAG 3347 itself run under AAP-03. The interoperability requirement it responds to is drawn from C-M(2006)0013 MC 533, NATO's Principles and Policies for the Maintenance of Equipment, which sits outside our catalogue.