I'll buy the beer.

Prediction, projection, position, protection. I'm not very clear on the finer points of my mother language apparently. ;-)

Here's how I look at it. FLARM calculates a projected flight path with a probabilistic "error radius" determined based on flight parameters to estimate a likely future position (assuming no change in control inputs) and then maps these paths to estimate likely conflicts and warns if it finds one. I consider that warning a prediction - if nothing changes the two aircraft will likely collide. Sure, it's an estimate but I still consider that more of a prediction than just putting airplane-shaped dots on a display and telling the pilot "you figure it out". I'd rather have a microprocessor and an algorithm than burying my head in a traffic display. I'd call that warning a prediction but maybe I'm being sloppy with the definitions.

The point is - FLARM will give you a warning only for pretty real threats. A traffic advisory system can only annoy you with constant warnings of aircraft in the vicinity whether they are a threat or not or leave it to you to find threats.by staring at a display. You need to project a flight path with some precision to strike a balance between too may false positives and leaving too many possible threats suppressed until too late. Given how we fly I think FLARM does quite well. It's also why ADS-B will struggle to operate as a collision warning system for gliders - even if someone tries to plaster a collision projection algorithm on top of some Garmin ADS-B unit. PowerFLARM throws out the ADS-B information if it detects a target with both FLARM and ADS-B Out.

9B