Mechta, if a Flarm or PCAS goes into audible alert mode (for Flarm, I mean not the single bleep that a new contact is detected but the loud continuous bleeping and lights flashing that mean a collision is imminent) the first thing to do, if not already doing it, is to look out ahead and between about 10 and 2 o’clock. If you are approaching a near-head-on collision, you have minimum time to see it and react quickly. Probably the best action if that is the sector of threat is to turn right. On my glider, both PCAS and Flarm are right on top of the instrument coaming so within the field of view anyway.
If no threat from nearly head-on, you have a bit more time to do something, so seeing which direction Flarm says the threat is from seems a good idea. It does not mean that there is no other threat, without a Flarm, in some other direction, and your only protection for that is lookout anyway. In my experience, and that of others who have Flarm, it improves your lookout. All the detractors are those with little or no experience of using it.
The cheap PCAS I have does not indicate direction. If it shows reducing distance, and I can’t see anything within the field of view, I have to turn and try to see the threat.
Would you really rather not know if somebody is coming at you from behind? That is the geometry in which the majority of collisions happen, I am told. I have decided I would rather know and be able to do something about it. If others don’t want to, it’s a free country, and they don’t have to. It might be their funeral, as it has been for 3 glider pilots.
Chris N.