Referring to the same figure, as part of the Summer series (left hand key) of tests indicates that test point 1 was used for the Stinger Trials, which sits at ~6.5 km of simulated distance.
Alternately Scenario #9 of in Table -5 (PDF page #23) is listed as an AH-64 at 6.5km.
and is confirmed to be used against MIM-72 & FIM-92 crews in Table #6 on the following page.
Implying that you can even lock helis with Gaijin’s AMAZING helicopter IR modeling. Why, I’m lucky if I can lock a helicopter 1km away. (True story, on the cold maps during cloudy weather you will not be able to lock a heli with IR missiles until they are effectively crawling inside your colon)
Imagine being able to just spawn a LAV at match start and decimate all the Russian Helios that rush in with guns and rockets. It may take 3-4 missiles. But I mean shit I got loads lol. Then just J-out and get in your Abrams(or whatever less freedom loving nation you play) and lose no spawn points really.
Apart from the ATAS, which for some reason is the Basic (FIM-92A) model instead of the RMP (FIM-92C) or RMP Block I (FIM-92E) missiles, even though the later variants are compatible with the ATAL mount.
ATAS is derived from FIM-92B and C. This features the same seeker as E and K stingers. It just lacks the Proxy fuze, some signal processing(?) and the Reprogrammable Micro Controller
Maybe it’s been posted before but I don’t know but I found this in a 1997 Budget for 1998-1999 it mentions upgrades for the Stinger to extend the range against Helicopters in cluttered environments meaning the helicopters flying in a cloudy-sky background or in front of mountains, I don’t think it’s much to go on but maybe it could be used as a source for a larger report for more modern Stingers like the FIM-92J/K having better tracking range than models like the FIM-92E or even earlier models if they got added in at least some scenarios like a helicopter sticking to mountains.