Quote Originally Posted by CarlOrton View Post
A good lab will reference your sample against fleet averages. Yes, ideally they will know YOUR engine better after several samples (to develop trending data), but one sample can still be compared to other similar engines.

When you submit a sample, you typically provide info on hours on engine, engine type, hours since last oil change, etc., so they can adjust the results in comparison with other like engines.

Regarding the types of material found in a sample, they will give a broad-range guess as to the source. As an example, they can determine the alloy. So, iron with nickel in it would come from a different component than iron with [insert metal here].

Most labs are relatively small, so if you document your unique situation (low avg run times, pre-buy, etc.) they can tell you that while a given material may be high in comparison to the fleet, x hours of flying is typically found to reduce those values. They're really pretty good forensic investigators!
Great info, thanks again. I didn't realize they kept a database of similar engines but I guess that makes sense. We walked away from an aircraft that had trending high iron content over a two year period, but that oil analysis company did not provide a baseline comparison for other engines. That would have been useful information. I think Busch mentioned in one of his webinars that he recommends Blackstone for oil analysis.