My question is whether air traffic control had the authority to simply order the military chopper to ‘stop’ or ‘reverse course’ rather than direct it to ‘look out’ or ‘be careful’.
The helicopter said they had traffic (the airliner) in sight. Once you declare you have traffic in sight, it is up to you to maintain visual separation. The controller could tell them to turn (as they had them on radar and was receiving collision alerts). I can easily see the helicopter getting confused with which traffic they thought they had in sight (as an aircraft was taking off), and all the ground lighting doesn’t help. I don’t fault the crew, as I have been in many situations like this-nighttime, background lighting, confused and overwhelmed controller. Once they were off their altitude, the controller should step in and confirm the altitude, sometimes this is a wake-up call and gets you back into your proper scan. Sad none the less.
Unfortunately the ATC personnel assigned to the radio frequency for the helicopter flyway had been allowed to go home by the supervisor, essentially leaving the helo flyway unmanned by ATC. Heads need to roll all around here.
He had the authority to order the CRJ to go around when he saw the helicopter on radar flying out of its assigned corridor a full minute before the impact.