If you have ever crashed a drone, it's not a pretty site. You're soaring your bird along, enjoying a wonderful day. Suddenly, a gust of wind or an obstacle you didn't see turns your UAV into a falling accident waiting to happen. The damage to your drone will be bad enough, but what if someone is struck by the falling aircraft? They aren't that heavy, but they can be dangerous. Depending on the angle of descent, it may come down like a guided missile. A fellow drone pilot told me of a time his vehicle seemed to lose control and darted into the ground at 30 knots and a 45 degree angle. Had it hit someone, they would have been seriously injured. The impact from the crash into a person would be terrible, but the other side of the coin is that just because the drone crashes into something, that doesn't mean the motors stop turning the props. If the motor isn't damaged, and it is still getting power, those RPM's will still be cranking. Those propellers are not forgiving at all. They can cut through flesh will all the grace of a food processor.
Enter NASA. Two aerospace technologists at NASA Langley Research Center, have developed crash landing software for drones. In several flight tests, they have been successful at vectoring a craft into a ditch or a swamp. The software has a national database of "safe" crash sites and whenever it detects the vehicle is in trouble, the software takes over, tries to right the aircraft and put it down in an area that will, ideally, not injure any people or property. There are still a lot of kinks to work out, but early testing looks promising. With more and more drones entering the skies everyday, including retailer's plans to utilize UAV's for deliveries, the need for this type of software is great. NASA is not planning on selling the software, but intends to license it to drone manufacturers. As an amateur pilot myself, I would love to have this software on my bird. It could prevent a tragedy.
Source:
http://fortune.com/2017/05/28/nasa-drone-crash-land-software/