Help needed with calculated member formula (finding children)

First post here folks. I have lots of JQL experience, cutting my teeth with eazyBi…

This is what I have. The below is returning issues with a ‘work type classification’ value of run the engine
[Work Type Classification].[Run the Engine]

What do I need to do so that I can get the child issues of any issue with the above value?

If there is an epic with ‘run the engine’ as the value, I need to return all the child stories.

Thanks