I wonder if there are any instances where Flarm units have been installed in a helicopter fleet? Are there factors with the rotors interfering with the exchange of data between the units which is essential for their full and satisfactory operation?
The strong point of Flarm operation is that the trajectories of potentially conflicting aircraft are constantly analysed, updated, and if a probability of collision is flaqged, both audio and visual alarms are presented in both aircraft - at least that's the intention / expectation. We've certainly found them to be useful - and even essential in high density glider operational sites - especially in contests. I've no idea how other position reporting systems operate, and what they offer in a situation like this, but I can't altogether escape speculating that a fleet of aircraft operating in regular close proximity with even just a stand alone Flarm system installed and operating in all aircraft would have just one more reserve of safety - one less hole in the cheese - additional to lookout, radio calls (and acknowledgement) and other SA factors which we all know about and use, but which can have their rare breakdowns when bad things can (and do) happen.