Reply #58: good questions

[Woody Box]

Now, it seems to me that if this is the case, there must be some ATC activity relating to the flight that took off at 8:23. After all, it couldn't have just trucked onto the runway and taken off without clearance, or the people in the tower would have been screaming blue murder. So, did the tower clear two different flight 175s? If the first plane wasn't really flight 175, is there a BTS entry for a different plane that matches its takeoff time?

You're right, of course, and I'm curious how controllers handled the 8:23 plane. My take - see my post #57 - is that both planes were part of an exercise, and that a few ground controllers knew about that.

And no, there is no BTS entry for a plane taking off at 8:14. Conclusion: the 8:14 plane - the one from the ATC transcript - was not in contact with United Airlines because it didn't send ACARS messages.