Commanche 3 is a helicopter sim by Novalogic, which uses 'voxels' for rendering the landscape, which created a really awesome landscape for flying for its time.
Some of the voxels are, for the lack of a better word to described it - 'puffy' and sort of clip a bit so when you land on the ground and they dig in a bit, creating a visual effect just like tall grass does to a helicopter landing gear.
Although it wasn't exactly realistic and based on a non-existant helicopter (the Commanche project was stopped I believe), it was the most fun I had with a helicopter simulator, and just have many days going through it imagining I'm driving Airwolf, flying low over the landscape, hovering in place to observe the enemy and calling for artillery or unleashing the chopper's firepower on them.
The landscape loops; that means if you see a rice field below you and keep continuing in that direction, then you will see it again. There are sceneries like trees. It was a very nice game/sim that balances play,simulation and fun quite well. I love the espionage / intelligence gathering missions - it's basically Airwolf.
Quite a lot of thought went into the game as well, as there are even auto rotations in the event of an engine failure (although the engine takes damage, it doesn't really just fail completely - you can limp the aircraft home) the manual states that you can actually turn off the engine mid air, autorotate to the ground, gear down and flare slightly on landing, and do it right you could actually get away with some gear and frame damage.
Trying to describe the game with words I can only do so much, the experience for Commanche 3 was so vivid and great that I cannot fully describe this into words.
I no longer have the sim, and I miss it much.
Novalogic ruined the 4th version (Commanche 4) with a stupid mouse-driven shoot-em-up-helicopter-simulator that just doesn't work, it was too time demanding, and most of the time I just don't know what was happening.