SAM's also use direct line of sight targeting. If I am behind a hill with only a very small part of me sticking out, your missile will probably hit the hill not me. There is not one SAM in existence that is capable of non-line of sight engagement.
Um no. It will try to hit the radar sticking out, and the radar requires you to stick out completely out of the hill, otherwise it would have no point of view to spot the enemy. If you LOS the missile right above the helicopter, the proximity fuse will still ignite the warhead at the exact moment it passes over the target. SAMs do not necessarily require direct kinetic contact.
Also, not all the Apache's have to stick their radars up at the same time. The AH-64D is equipped for cooperative engagement. If I have 4 Apache's hiding behind a hill, only 1 will need to expose his radar for a brief moment and take a look. After taking a look with the radar, the fire control system will digest the radar signature, consider the targets.
Sorry, but radar does not work the way you imagine it to be. You would need to fully scan the area, unfortunately the Apache's radar isn't SAR, so you cannot make a visual identification because SAR requires an exposure time and distance to pass before you can make it work.
If you spot up and get a whole bunch of returns, how much time are you going to spend studying each return to verify if its enemy, friendly, or civilian and as to what type of target it is. Not to mention if your radar is affected by EW and heavy EMF interference. Even rebar in a house can become part of the reflective clutter.
Furthermore, if we are using the Apache's to combat a landing, you will essentially will know that anything that moves out in the distance is enemy.
That isn't correct at all. It can be civilians moving in the way out of the enemy.
You form engagement zones; say a Apache is 4km away from the landing zone behind cover. It takes a radar look, and sees targets all the way out. You know that friendlies are at most 3km away from your position. Therefore, anything beyond 3km away from your position will therefore automatically be considered hostile.
Partitioning may not work when you are in a heavily populated area; when chaos is at a max; when your own communications and networking has been compromised and affected by ECM and EW measures. The west coast of Taiwan, especially the north is certainly is such a populated area. Furthermore there isn't that much hills in the west coast of Taiwan where you can expect an invasion (check Google Earth btw). What you're going to have is urban warfare.
