Originally Posted by
skippybangkok
Answer is "maybe"
Each metal batch is close but not identical. Analysis of trace elements can be compared to fasteners coming from same batch - assuming a sister plane used them and one can be removed for comparison
Sorry charlie - you need to understand how such fasteners are produced - stored and disbursed. They are ordered months/years in advance of use. They are produced and shipped perhaps on a monthly basis and put into ' temporary' storage by the boxfull. A given production shipment to Boeing of that same fastener could be split into two or three or four batches- at boeing that would be 737, 747, 767, 777 for example since some are used on every model- and part of the supplier production batch might be shipped to one of a " half" dozen suppliers just for Boeing. Other parts of that supplier production batch may well be shipped to St louis, lockheed, Airbus, etc.
But after splittting the " Boeing batch "and being sent to renton or everett or part of the batch being sent to a supplier(s) they are temporairly stored in the closest plant/assembly area before being daily put into ' nearby' to assembly rotobins- replenished at least daily or every other day dependinng on parts, assembly, production rates, etc. Some of the same fasteners in that rotobin ( for example at the ' bottom ' ) may well be three to six months old for a given model.
So a chem/sprectro analysis may well show ' family brother" fasteners of that size- batch on most any part of any plane going back from weeks to months just at Boeing- and possibly any other aerospace company in the world.
IOW- as I first stated, absent a unique flaw in that fastener or out of tolerance composition, tracing that fastener to a ' sister' ship has a VERY low but not quite ZERO probibility of being useful.
