I have my app setup to give me a low battery warning at 30% and again at 20%. At 20% I usually bring it home manually (p mode) with about 15% left after landing. I have noticed on two occasions (the latest one being yesterday) that if it is still flying with about 10% remaining, it just drops hard to the ground even though I am "controlling" it. On both occasions My altitude was fairly low (about 1-2) metres) and the Phantom 3 was not damaged. Is there a setting that I should be checking? Is this a RTH feature? Any help would be appreciated. Thanks