lonewolf 50. you are the KL radar controller watching 370 on the screen in front of you. you instruct it to contact HCM then watch it continue NE. the moment you see its label vanish ( when the aircraft transponder stops), you reach for the phone to ask HCM atcc fellow controller on a direct line, whether he has ok contact with 370. he says no and may even tell you then that he can see it has turned back. you and he there and then initiate standard search and rescue procedures. atcos do not have to refer to anyone else first, their responsibility is to get the procedure under way without delay because time is of the essence. adjoining atccs are informed at the same time.