Fly Maui, I need help with a phantom four, I want to fly over a ravine, but I’m afraid that the drone will drop down to the 400 foot recommended high elevation, how do I keep the drone at the same height of the takeoff from the cliff ?
It wont. It will still see "zero" altitude if you are flying level with the cliiff. Your altitude will go negative after that. Unless, you are in an area where flight is restricted. Then that is another can of worms, so to speak.
Did I not tell you that there was? Again, unless you are in a restricted area, without variances and/or FAA authorization of some sort. Pay attention to the regulations and you won't have these type of questions, and you may also learn a lot...
I just offered the explanation. You can fly below the launch point. You have to be aware to reset the RTH altitude far above your launch point. And what would learn from viewing this? Nothing. I fly completely legally, safe and abide by any regulations set forth per the FAA, and/or AMA. So there is not much to learn, other than possibly some additional vidography tips. And yourself?
The Phantom will not drop. It will maintain the altitude you are flying, unless you manually drop it. What is it about that you don't understand? The altitude limit is a regulation, not an indiscriminate altitude determined by the aircraft. If you launch above your desired altitude there is nothing to stop you from descending or ascending.
The aircraft is maintaining it's altitude regardless of what the ground below it is doing. When you fly out over the cliff your display will show you at the same altitude because it's all relative to your TAKE OFF POINT. It doesn't know the ground is now much further away... that's up to the operator to know and understand.
With all due respect, I don't know that you've fully grasped the manual and everything about the aircraft enough at this point. You might want to spend some additional time reading the instructions and getting a better understanding of the complete system including the controls, aircraft, and the flight App.