Altitude Dilema

[KBW]

So correct me if I am wrong. The Phantom records the altitude at your home point and calculates from there. I fly in mountain country and DJI Go can say I am at 400ft but I am actually 20ft off the ground on the side of a mountain. I am assume what we see on the screen is not AGL but height from the home point. So if you start flying from the top of the mountain and go down you can never be above 400ft but may be thousands of feet off the ground...... If you are flying from the top of the mountain and someone wants to question the legality what is the answer? I assume the answer is no more than 400ft above what is below you but that data may not be available on your screen.

KW

 

[alokbhargava]

As far as you are within 400' of your home point, you are ok even if you started flying at the summit.

 

[Meta4]

So correct me if I am wrong. The Phantom records the altitude at your home point and calculates from there. I fly in mountain country and DJI Go can say I am at 400ft but I am actually 20ft off the ground on the side of a mountain. I am assume what we see on the screen is not AGL but height from the home point. So if you start flying from the top of the mountain and go down you can never be above 400ft but may be thousands of feet off the ground...... If you are flying from the top of the mountain and someone wants to question the legality what is the answer? I assume the answer is no more than 400ft above what is below you but that data may not be available on your screen.

It's the same situation for most pilots of small planes because they don't have laser or radar altimeters either.
The FAA understands what AGL means and that your altimeter reading is not necessarily height AGL.

As far as you are within 400' of your home point, you are ok.

Your home point is irrelevant if you are concerned about legal heights.
No-one cares how high you are above your home point.
What matters is how far you are above the ground below your Phantom.
On flat prairie land, there might be no difference but if the landscape is a lot more 3-dimensional the difference can be significant.
As in the illustration below.
You could take off from the top of the mountain or the bottom but that doesn't change the legality of your flight altitude.

 

[alokbhargava]

Your above case is valid if you are already in a hilly area.

I have hills with AGL as high as 1500' at about 2 miles from my home that doesn't mean I can fly at 1500' around my home.

 

[Roamer105]

If the cartoon is to show the bird flying more than 400' above ground level (point straight below the bird) neither operator positions make it legal.


Sent from my iPad using PhantomPilots mobile app

 

[davidkfx]

I try p4 and for making a topográphic analisis the p4 give me altitudes in mts abovedada sea level and thats great anybody knows in what way you can change that in p3