The plane had shut off its communication devices; there was no response to any calls.
Affected by the Earth's curvature, long-range early warning radars have limited detection distances at low and ultra-low altitudes.
It's like when someone tilts their head up; they definitely can't see their own feet.
Because of this limitation of radar, military powerhouses have their pilots rigorously practice ultra-low altitude penetration skills and develop equipped early-warning aircraft to 'look down from above' from high altitudes, which aren't affected by the curvature of the Earth.
In the current scenario, the government plane was either going to crash into the sea or it was attempting ultra-low altitude flight.
The two urgently launched heavy air dominance fighters had phased array radars that could detect targets at mid to high altitudes from a farther distance.
But for ultra-low altitudes... over the vast sea, with turbulent waves, there was too much electromagnetic clutter.
