Hmpf; that's what I get for posting and not reading new posts.
From Zanzetkuken's post, it seems as if we have two issues:
a) The UFO kills all nearby threats before landing (or at least those it can detect)
b) Should the UFO be threatened by ground troops, it will take off.
This implies we have to find a way to physically keep it from taking off (or shoot it down before that). One idea would be to deploy several Bumblebees to the area and hope it's easier to shoot down when starting; or use the SAMs for the same. An alternative is to deploy artillery closeby, then fire while the UFO is on the ground.
In total, my vote is still for the helicopter in the hopes of getting a system to quickly deploy (from cover) our forces.
I agree absolutely with the problem. I do not see the helicopter doing anything because the enemy can just leave whenever they want to. At best I see helicopters getting us a few corpses who were slow getting back to their ship, but I can't imagine a single-thing crew being that reckless. Helicopters are not exactly quiet and it takes a while to get the things aligned, also, they are slow, so they are not exactly going to be deployed right at the edge of 15 kilometres when the thing lands...
I worry about getting the bumbles to the area and their ability to actually it the target enough to down it. I wouldn't know the penetration on their artillery but a glancing shot is not going to do much and the bogeys are going to be quite the nippy little brats.
The S.A.M.s seem too localised for their guidance systems. You pretty much need the enemy to fly over the S.A.M. site and then fly over the observation.control post and you also need the missiles to be as fast as the aliens, which, well, 2400 kilometres is a lot for people who have yet to break 400... IF the enemy lands within view of a control post then the S.A.M.s ought to do a marvellous job of hitting the craft while it is on the ground and thus crippling(and reducing it to a field of debris no piece larger than a coin, but baby steps...) it. But can we really expect them to land within view of a control station without destroying it first? Mobile control stations may work, somehow, but that is a tall order.
Artillery seems like a sound plan, but spotting is going to be a pain. IF the artillery hits then yes, it ought to make a dent(Though 320mm howitzers would be a joy for this work, airburst if you want to see their crew...) but hitting the small ships that we are seeing now would be difficult, and waiting for larger vessels is not a good plan.
My missile plan has, say, a couple dozen launched from the air at, say, 20 kilometres, and then steer themselves in against a landed target at high speed. They take fire for less than a minute, and are still a threat even if they take a hit because kinetic energy doesn't just vanish, and if even one of them makes a solid strike you get a half-ton of rocket and rocket fuel hitting the target, at which point the artillery shell in its nose goes off and punches a bunch of excited metal wedges through the armour to go find something to play with. Oh, certainly, I am willing to entertain that it may be difficult to get more than a few scraps of exotic material from the wreckage, but if the target still feels like flying after that then I fear we may be in more trouble than we first thought...