Fans will tell you there’s always two things to look for in a “Star Trek: The Next Generation” episode to ensure that it has the best chance of being a good episode. Does Jonathan Frakes’ character of William Riker have a beard? And is the doctor Crusher?



That basically says all the good episodes run from the third season on in TNG, because Riker grew a beard by Season 2, and Crusher and Riker’s beard didn’t appear together until Season 3, since Diana Muldaur’s Dr. Pulaski had stopped by for a brief one-season run.



So why did McFadden leave, only to come back? William Shatner wanted to know, and was sure that he asked in his new TNG documentary “Chaos on the Bridge,” which will be released Aug. 1. Here’s a sneak peek, and be sure to look for Shatner’s new documentary on digital platforms everywhere.