caves

HI, i will fly inside a caver or cave, how i can protect the top of my phantom 4 and the propellers? Whiteout any GPS signal what happen with auto RTH if o louse signal?

Up the Uinta Mountains in the Pole Creek Sinks, Utah. A great place to visit and the lower pole Creek Cave is fun to explore you can only go into the cave during the fall though, any other time and the cave is flooded, the upper section is always open its very small only two hallways it was made...