Originally Posted by
InfrequentFlier511
At one point in the edited atc recording, I heard something about "primary contact only." From the edit, atc started asking other aircraft to look for debris very soon after, so it could be atc losing the ADS-B signal amongst ground clutter. Did the transponder stop broadcasting before impact, and what - if anything - would that mean?
Primary contact means the radar facility is painting a target on radar but they are not receiving the transponder or assigned code. This can also be caused by birds.