When a high-reliability electronic component fails in a satellite, an aircraft or a weapon system, the first question is technical: what physically went wrong? The answers that matter to the organisation operating the equipment come later, and they are not technical. They concern whether the specimen may be opened, who may see the results, whether a different supplier’s part may replace the failed one, and who has the authority to release the repaired equipment for use. The manufacturer of the original component usually knows its design, process history and test data better than anyone else, and that knowledge can make it the default investigator of its own product’s failures. For European buyers, maintainers and prime contractors, the dependence this creates is easy to miss, because it sits inside quality procedures, sales terms and approval rules rather than in a visible supply contract. A Europe that wishes to sustain its own defence electronics therefore faces a narrower question than whether it has enough laboratories. It must know under what technical, contractual and institutional conditions its organisations can establish why hardware has failed without depending exclusively on the original manufacturer, and whether they can turn that diagnosis into evidence that an authorised body will accept for disposition, repair, supplier substitution or a dispute over conformity.