The MiG-31BM's Zaslon-M PESA (passive electronically scanned array) radar, based on the legendary Zaslon, the world's first ESA, detects hostile aircraft at a staggering 400 km range, meaning that it could detect and track the F-16 long before the latter is even aware of the MiG-31BM's presence, to say nothing of the latter's 400 km range R-37M missile.