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Certified v Uncertified


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Hi All,


Can anyone tell what exactly is the difference between certified and uncertified aircraft engines ?.


Do certified engines have different (better quality) parts ?







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Guest micgrace



Certified means tested to a design standard eg. 101.55


i.e. test run for various times at various loadings to strict


standards. Look 101.55 up (not the only standard) but the one most applicable to RAA.




does not mean substandard parts. All certified engines started as


uncertified at some point till testing and other paperwork requirements


were passed.


Your you beut certified engine rapidly becomes uncertified the second you change a plug or oil (in GA anyway and God help you if you do)


for our purposes it was certified, but to be brought back to certified


status it's off to the LAME with fistfulls of dollars. IFF they'll do




It's actually a little more complex than that, I hope that helps somewhat





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Guest Fred Bear

Depending on the engine manufacturer, certified aircraft engines can


also be built to more exacting tolerances. Certified also equals


expensive. A good example of this is the Rotax 912 and Rotas 912A, with


the latter being the certified version and far more expensive. Aside


from price and paperwork the engines are 99% the same, however the


certified version is more likely to have been checked and re-checked.


It's a bit of a catch 22 however, because it's not like an engine might


be a little dodgey, so they just call that one a non-certified model,


it's more about processes, quality assurance, paperwork and liability.


Hope that muddles things for you enough.





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Guest micgrace

The processes are mainly the same if certified or uncertified. Mainly paying for the legal liability (plus testing etc) if certified. If uncertified you get to carry the liability not the company.




to small production runs a manufacturer is hardly likely to have any


changes in production between uncertified/certified. This simply


doesn't make economic sense.





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