Its not going into landscape, your computer is always in landscape, NVDA is just telling you that because FSX is switching resolution, and if your computer has a touch screen, which yours does, I can almost guarantee it, and the suite of sensors that go with rotating or flipping it, its just saying that because it knows about it. On a regular computer without a touch screen, you never hear about this, because its just not something the system  knows about, or to be more correct, you will hear about it if you manually rotate the screen using your GPU manufacturer's control panel, or a set of hotkeys, its just in this case, the computer is able to switch on its own, and so NVDA is reporting when its doing that. In short, there's nothing you can do about this, you might be able to stop the process from happening by setting fsx's resolution to be your monitor's native resolution, and make sure your settings under windows is set to your monitor's native resolution, and not some bullshit like 800X600 or 1024X768.

So my lappy has the ability that the screen has no stop built in. It can go from lid shut all the way to where the back of the screen is against the bottom of the computer. This is tablet mode, and you can set windows to automatically switch it. By the way, is this a gimmick, totally, I'm just telling you what it is for. So when in this mode, you can hold the computer like a tablet, it even has its power and volume buttons on the side, which is no end of frustration when I hit power to sleep accidentally, but changing it I still don't want to do because I use it. Anyway, I can then rotate it into portrait mode and it would do as a tablet would, and flip the screen orientation accordingly, then NVDA would report the change.