But that's not the case. You can see the 'd20' yourself, and it's not loaded. Right now, it's just like one of these people who roll three natural ones in a row and start ranting how it's 'totally impossible'.
One can headcanon all sorts of things in X-Com, especially since the entire premise (light infantry vs invaders with spaceships) is entirely implausible without some serious SoD. Perhaps the Skyranger was hit by alien AA fire, lost an engine and between the UFO and the barn was the best the pilot could do short of totally crashing? Maybe he's an alien sympathiser? A hybrid infiltrator? Maybe the UFO has medium-range holographic camouflage? Maybe X-Com hires the cheapest pilots they can find? Maybe it's an AI pilot and this was mistakenly a training run? Etc.
All it comes down to is whether it makes for interesting gameplay, and it does. You could also complain about the fog of war, since it's quite unbelievable that X-Com has no maps, no cameras on the aircraft, and the soldiers never look out of the windows. But it's more fun to play with fog of war and uncover the map together with the enemies, as exemplified by countless tactical games.
Now, if you're really bothered, you can learn (minimal) map making and change the maps and map scripts so that there's a bigger buffer zone around the Skyranger (and other X-Com craft). But this probably has other downsides, since nobody has done something like that as far as I know, and there's been quite a bit of very sophisticated modding going on for years.