@Concentric: if that's the case, than one might worry about a whole batch of gears made when that serial number (the failed one) was manufactured ... if one wasn't baked for hydrogen embrittlement relief, how many others weren't? (Caveat: this response is solely related to Concentric's "what if" question, and is not an assessment of factual evidence revealed so far regarding the material condition of gears in the accident aircraft).