article_snippet.sent: Behaviors not quite conducive to the activity are readily apparent.
article_snippet.sent: It is a period of almost constant supervision.
article_snippet.sent: Aside from observing and checking performance criteria, wouldn't at least one instructor have noticed behavioral issues in such an intense environment?
article_snippet.sent: And wouldn't a fellow trainee have noticed also?
article_snippet.sent: Was that not in and of itself a red flag?  
article_snippet.sent: Again, no one observed issues.
article_snippet.sent: That determination can be made through performance observation of typical routines, or perhaps through a simple conversation.
highlights_snippet.sent: There were likely warning signs during the co-pilot's training .
  