Originally Posted by
FullOppositeRudder
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.
No, no technical reason for Flarm not to work in helicopters. And a great option, as in this case both helicopters belong to the same fleet, and habitually share the same airspace.
Both mishap helicopters were also already equipped with ADS-B Out (no difference here to „Flarm Out“). The important difference you point out is in the software algorithms used to analyze targets (as received by the ADS-B In or Flarm receiver), in order to avoid nuisance alerts and to prioritize the most relevant threat in a high density, VFR environment. As others have mentioned, many ADS-B traffic displays seem more suited for fast moving fix wing people on an IFR flight plan.
SkyDemon (iOS nav app) does a fantastic job in combining and analysing traffic data received (from several sources, including ADS-B and indeed also Flarm).
This would have been the picture similar to what the departing helicopter would have seen (with helicopter symbols, of course).
See the focus of this app on the 1 NM to 2 NM radius around your ownship in what the TCAS-style pop-up window? The landing helicopter would have got the same the picture, relative to their current position.
And a few seconds later, the initial proximity alert would have turned into a collision alert.
Important to note that collision alerts are sent as verbal warning to the crew, via cable or Bluetooth to the audio panel, or directly to the pilots headset. I am using this set-up for years, and can vouch for its suitability in a helicopter environment.