I’ve tested (well, to be more accurate I’ve regrettably used) both the R-27T and R-27ET extensively in Air RB and I am aware of the flare resistance of the popular IRCCM-capable missiles such as the AIM-9M, R-73 and Magic 2 from my own experiences with using them which I will be using for comparison. These are my findings:
Don’t even bother trying to fire them in a head on as they’ll always miss. R-60M’s are more useful in that regard and they don’t even have IRCCM and on some occasions it’ll also ignore flares.
I’ve tried firing rear aspect within 2 km to 1.4 km minimum with no signs of the target plane preflaring or cutting afterburner before missile leaves the pylon. It goes for flares immediately - exactly like an R-60/M would. In a similar case with the R-73/Magic 2, it will simply ignore flares and hit the target no issue.
I’ve tried side aspect, no dice - same result.
I’ve also tried it with IRST to see if that would change things but fun fact - no. In fact, IRST itself is susceptible to flares so 9 times out of 10 you are locking onto a stray flare and if you do finally manage to lock the target you’re well on your way to dying by someone else.
It seems the only way you’ll ever get kills with the R-27T/ET is from long range against someone either flying super high above you and can’t see the missile coming or someone that’s not paying attention and not actively flaring in the furball - well, if their teammate’s flares doesn’t get in the way that is (yes that’s happened… multiple times -_-)
I’ve come to the conclusion that the “IRCCM: Yes” bit in the missile description in-game for the R-27T and R-27ET are just there for decoration because the missiles themselves are just a faster and more agile R-60, which is a shame since the R-27T/ET should literally have the same IR seeker as the R-73.