and landing without a crash is impossible - that's the truth I have to face in FSX. I didn't make the model myself, so changing just a part of it (i.e. correcting the platform only) would require getting the source objects from the developers. Since I'm not distributing anything, I was looking for "the private way" of only adapting it slightly to my system requirements, which I considered to be a "quick solution" with MCX.
The actual truth is that you will crash land as long as you allow it, face only your own resignation to the fact. You have "the source object" and you have MCX with which you can edit the crash box granularity. Granularity: a big "grain" is a single box that covers all the boundaries of a model. If the model to which your landing platform connects forms a cube, then low granularity would work well for you. If your model is shaped like an aircraft carrier, higher granularity can eliminate crash boxes in open space, like between the tower and flight deck. Higher granularity, greater definition in the crash box "mirror" of the model, adds complexity to the model, so it is probably impossible to render a model to which the crash boxes have been matched on a molecular level, but that would be the ultimate goal.
Also
this thread relates to some of the quirks of working with MCX and Bjoern's understanding that there is a relation between bounding box and the dimensions of the crash boxes.
This is a default library object, "GEN_hospital 1." Of particular note are the two bounding boxes, one for the building and one for the helo pad, how the crash boxes are tightly stacked like building blocks and how the landing deck is free of crash boxes even though they are present on every other horizontal surface. I should also say that I had to disable crash box rendering in order to position the screen shot because the added complexity slowed my computer.
Here is the model re-exported using the MCX default settings. The options panel allows the user to select the XtoMDL crash box values or chose values set by MCX. Note that crash box granularity of "1" makes far fewer, coarser crash boxes and while the landing pad remains clear, it is now much easier to trigger a crash by passing close to another portion of the model.
Does your model have a hard platform for the landing pad?