Loading ...EVERY commercial airliner, and other planes flying in ‘controlled airspace’ near an airport has it’s altimeter reading encoded into the radar sweep that the controller sees on their screen. It identifies the plane, and it’s altitude. That’s how they know the jet was at some 350 feet and descending.
Military aircraft have different rules, and frequently ‘exempt’ themselves from customary readouts. For instance, the Helo did not have it’s ADS-B position transponder running, which was also required for the Jet. It’s possible the Helo did not have it’s radar altimeter running, so the controller would have no readout of it’s altitude…. leaving the controller to ASSUME the Helo was adhering to the 200ft max altitude rules.
But the fact that the Helo collided with the jet reading out 350ft tells us that it was in violation of that 200 ft limit.