Suspected unapproved parts are those aeronautical parts that should be deemed unairworthy. Therefore they are not eligible for installation on an aircraft or another aeronautical product. Their design, manufacture or distribution is in conflict with aviation regulations. This means that such a part may not have an approved design, may be manufactured by an unapproved manufacturer, distributed by an unapproved distributor, possibly even taken from scrap aircraft while bypassing mandatory and costly shop inspection and recertification processes.
Indicators for an unapproved or bogus part may reach from missing, incomplete or counterfeit certification, missing or manipulated identification plates, physical aspects like surface grain structure, shape, colour, or weight deviating from the removal part, to any indicators of poor workmanship as well as a suspiciously low purchase price.