Let's see if I can count out a few reasons to this not to happen....Better pilot training. Everyone I've worked for flying an S76 always emphasized getting the disk up out of harms way when running on the ground. No reason to leave it low like that when just parked and idling. Some of the S76 had a kit installed with a warning light and audio warning if the cyclic was too far forward. Seems like a reasonable expense to install on a ship used for corporate work. There is also the option of stopping the blades if you have a manual rotor brake. What else? Turning off the autopilots when on the ground so that the servos don't inadvertently drive the disk down (I think this happened with a Bell 222 on with the same result as this). OK, I'm out of fingers.