During the inspection of fan, compressor and turbine blades, what is the method of identification? For example during borescope inspection, what is the mode of identification of stator and rotor stages? Is there any form of labeling on these blades?


1 Answer 1


I don't know specifically for a CFM56, but in general: fan blades are usually identified by a dimple on the spinner (blade #1 is next to the dimple and number from there). High pressure compressor blades can be identified by special "locking" blades, which will look different from the others. They will have screws in them to "lock" them into place. These line up with a feature on the rotor, so they are always in the same place. Locking blade will be #1 and number from there. I'm not sure how high pressure turbine blades are identified. LPT blades are usually identified by finding the #1 fan blade and rotating it down to bottom dead center. Then the LPT blade at bottom dead center is considered blade #1.

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    $\begingroup$ Related: CFM56 - Borescope inspection Page labeled 14 in the document explains this for a CFM56-7B. Next page shows the index hole. $\endgroup$
    – mins
    Apr 1, 2017 at 10:27

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