I have a problem going to tws with the su-27 radars. I press alt-i while i'm in bvr mode in scan mode but it does not switch to it. I have alt-i in the input options as the key to switch to tws. At first i thought the Su-27 didn't have tws cuz when i pressed alt-i it wouldn't switch. But while i was playing i suddenly went into tws mode, instead of being in scan mode it went to tws. I wasn't able to reproduce it again until i found out the way to do it is to lock on to a bandit from scan mode and then shoot him down with guns and when he crashes i lose my lock and it returns my radars to TWS. thats the only way i'm able to get to tws mode. I have lock on 1.02. Either is a bug, or i'm not doing the right procedure. TWS works for me when i use the f15c though.

There is no TWS mode in the Su-27. There is TWS in the F-15 and ALT/I is how you switch it on in the F-15.

What can happen in Russian jets is that when radar lock is lost, it will automatically swap into EOS mode to attempt to find the target with Infrared. Maybe this is what you are seeing?

What exactly are you seeing on the HUD or HDD in the Su-27 that makes you think you are in a TWS mode?