If their transponder failed, the pilots may or may not have known there was a problem—and if it did, you’d think that ATC would’ve been all over it, because planes suddenly disappearing off radar is something that should obviously raise an alarm.
Still, I believe one of the planes was traveling at an invalid altitude. I’m not sure how they do it in Brazil, but under new rules in the US and a lot of the rest of the world, planes traveling east fly at odd thousands of feet (31,000, 33,000, etc.) and planes traveling west fly at even thousands (32,000, 34,000, etc.) A thousand feet is plenty of vertical separation. One of those planes was at the wrong altitude, and I’m guessing it was the Embraer if their transponder wasn’t working. (Transponders transmit the plane’s altitude back to the radar—without them, the radar can’t determine the plane’s altitude, it just shows a dot.)
}:-)4
Apparently, Nifong has a twin in Brazil.