I am wonder what an experienced pilot will do. If I wish to take video of a cliff down 200m and I am sitting at the top of the cliff. What are the consideration to make a safe and successful flight.

Be prepared for turbulence.

DTK, make sure you maintain a Visual Line of Sight!!! You may lose radio signal if you fly too low below the cliff. Safety First! Ken.

If you are flying over sea, when below the horizon, you will find it hard to see the drone and even harder to judge the distance above the water. Also keep in mind the water level can vary greatly with swells. Wind speed/direction can also vary a lot around cliffs.

Mark G.

My further questions after hearing everyone.

1. If I set RTH altitude at 20m how would the machine interpret this setting at sea level. If it use the sea level as it reference, it will never be able to land on top of the cliff.
2. In order to avoid turbulence close to the cliff face, should one fly farther away from the cliff on its way up and down to sea level

It will return to home at 20m above take off point.

DTK Posted at 2017-5-15 02:05
My further questions after hearing everyone.

1. If I set RTH altitude at 20m how would the machine interpret this setting at sea level. If it use the sea level as it reference, it will never be able to land on top of the cliff.

Mark is correct about your first question. As far as for your second question, that would be a good approach.