there has to be coverage on 135.7, MB Tower, EN Tower, CTA broadcast, Yarra 132.1 and hope that everyone is listening and gets one of the calls
This has always been the defense that it's safe - all those calls. The problem is that the parachute aircraft can't drop with aircraft below. With so many calls, 1 pilot and 2(?) radios and a clearance to get - who's listening for the calls that come in from potentially conflicting traffic below?