What aircraft?
If f-16s do not have radar that can acquire a hostile aircraft, then that means that they are vectored to the target.
So assuming a very dark night or IFR from 400 ft. to 12,000 or so, which certainly is not uncommon, how do F16s get visual contact?
Having spent more than a few rough nights on instruments, I can't imagine a radar vector to wingtip to wingtip on such a night.
In past years, I never had the time or the interest in military aviation to ask, but this accident intrigues me because I spent so much time in that area.
Closing to get visual contact at night is darned hard.
Closing to get visual contact IFR (in the goo) is darned near impossible.
At night in the clear you run an intercept profile based on many factors and you usually maneuver to the rear of the target aircraft and monitor your closure rate to creep up. For a re-join after take-off you do the same, or reforming at night after doing a mission you do the same thing, or if you are rejoining in a turn you use perspective (knowing what his external lights look like and maintain that spatial relationship as you close) and you you know the rejoin airspeed to control your rate of closure.
Under IFR, in the goo. . .whew. Easy to maneuver to the rear and closing somewhat on the other aircraft can be done. . .but depending upon how thick the goo is, you usually stay in trail and never close to fingertip. If you are in that much goo, you remain in trail.
Cheers