Crossing the valley

[Shadowcatcher]

First of all I want to thank the members for your quick response on my previous question on RTH. Next question, there is a gorge that on the opposing side is a cave that is inaccessible ( unless you repel ). My question is if I take off say at an altitude of fifty feet and fly to get a close view of the cave and for some reason have to hit RTH, will the difference in elevation ( bottom of the gorge ) effect my RTH hight to return and land? Also do the downward sensors recognize water as it would land ( mini ) ? I've only had my craft ( mini ) for a week and I'm not going to fly any farther than my back yard until I'm totally familiar with the functions, controls and rules. Also will airplane mode effect any flight functions ?
Thanks

 

[Thomas B]

All altitude is relative to TO point. If you (the drone) are above the set RTH height it will just fly home at that altitude with RTH and land.
If the set RTH altitude is above current altitude it will ascend to that set RTH altitude and do the same.
You can look at your controller indicated altitude to know what will happen if you remember what altitude you set for RTH.

 

[old man mavic]

the downwards sensors do have issues seeing water as it reflects and disperses the signal from the sensor sender and receiver,and it can confuse them, all you have to remember with RTH height ,is the height you set it to, is only relevant to the height above the home point,how high it is from the ground when you press RTH has no bearing on the height it returns at,other than the fact as @Thomas B said it will either rise up to the preset height then return or if it is already above that height ,it returns at that height

 

[JoelP]

Let add that if you are in the US, you are only allowed to fly 400 ft. above ground level (AGL). Let’s assume you set your RTH altitude to 200 feet. If your canyon has a floor at 300 feet below your established home point, then portions of your return may be at 500 feet, which exceeds you legal altitude by 100 feet.

 

[Thomas B]

Let add that if you are in the US, you are only allowed to fly 400 ft. above ground level (AGL). Let’s assume you set your RTH altitude to 200 feet. If your canyon has a floor at 300 feet below your established home point, then portions of your return may be at 500 feet, which exceeds you legal altitude by 100 feet.

Unless you are w/in 400’ of the canyon wall... then all is legal.

 

[dronerdave]

Unless you are w/in 400’ of the canyon wall... then all is legal.

Isn't that rule a 107 rule? I thought Rec fliers are subject to 400 max no matter how close to a cliff face you are? Sorry if the OP is flying 107...I didn't see it in the OP's post.

 

[Capt KO]

400ft from T.O. point. If you want to go higher, better start climbing. So @ 5000 ft you can fly to 5400 ft. But how far away horizontal from HP above the valley floor 1000 ft below? I’ve seen so many videos here from people flying from mountains well above 400 feet from the valley floor. I just assumed it was legal as long as Vertical 400 ft above HP. Horizontal VLOS........correct? Hope so, want to go to top of Lookout Mtn. and film from qtr mile away. Way over 400ft. Guess not.

Happy climbing

 

[old man mavic]

400ft from T.O. point. If you want to go higher, better start climbing. So @ 5000 ft you can fly to 5400 ft. But how far away horizontal from HP above the valley floor 1000 ft below? I’ve seen so many videos here from people flying from mountains well above 400 feet from the valley floor. I just assumed it was legal as long as Vertical 400 ft above HP. Horizontal VLOS........correct? Hope so, want to go to top of Lookout Mtn. and film from qtr mile away. Way over 400ft. Guess not.

Happy climbing

the height rule is in itself somewhat confusing,it works fine on a perfectly level area of ground, and also if you fly from a low point, and climb up a slope at some point you will be more than 400ft high from your take off point ,but you might be only 50ft above the ground where the drone actually is, and that is fine if there are no people or dwellings within 150ft of your drone,when i have been in that type of situation and have lost VLOS ,or i am not sure which way the drone is facing, i dont press RTH,i use the map and drone orientation triangle and yaw till i am facing home, then return till i can see where i am, then carry on with the mission ,also as you return just reduce height and then you will still be under 400ft as you descend

 

[Capt KO]

Yep. Just figuring out how far out, horizontal, I can fly from top of a mountain thousands of feet high. From videos I assumed VLOS.

 

[JAW]

I'm still not 100% clear on this.

Assume I take off at the edge of a gorge 500 feet deep. Once I fly out over the gorge I am technically in violation since I am above 400 feet AGL. This is the assumption I am going with. Is this correct? ( recreational pilot in uncontrolled airspace )

 

[old man mavic]

yes you would technically be 500 ft AGL the moment you flew out,but remember the 400 ft AGL is to keep a buffer between us and manned aircraft who have to fly higher ,so the chances of an aircraft being in that airspace are pretty remote, and if there was a rescue heli in the area then you would not have taken off in the first place, all these rules are there to prevent contact ,and all you can do is be aware of your surroundings and fly with the rules in mind

 

[dronerdave]

I'm still not 100% clear on this.

Assume I take off at the edge of a gorge 500 feet deep. Once I fly out over the gorge I am technically in violation since I am above 400 feet AGL. This is the assumption I am going with. Is this correct? ( recreational pilot in uncontrolled airspace )

I agree and if I'm flying legally and something goes wrong, at least my intentions were to fly legally as opposed to having to explain why I was in uncontrolled airspace in the first place prior to an incident. Myself I do think we should have a horizontal buffer of some sort.

 

[JAW]

. Myself I do think we should have a horizontal buffer of some sort.

+1

 

[Thomas B]

I'm still not 100% clear on this.

Assume I take off at the edge of a gorge 500 feet deep. Once I fly out over the gorge I am technically in violation since I am above 400 feet AGL. This is the assumption I am going with. Is this correct? ( recreational pilot in uncontrolled airspace )

yes you would technically be 500 ft AGL the moment you flew out,but remember the 400 ft AGL is to keep a buffer between us and manned aircraft who have to fly higher ,so the chances of an aircraft being in that airspace are pretty remote, and if there was a rescue heli in the area then you would not have taken off in the first place, all these rules are there to prevent contact ,and all you can do is be aware of your surroundings and fly with the rules in mind

In the US you would be legal as long as you were within 400’ laterally of the mountainside regardless of altitude related to TO point.
For example in the U.S. if I TO on a 2500’ cliff and fly out past the edge of it I am legal as long as I stay within 400’ of the cliff face.

 

[dronerdave]

In the US you would be legal as long as you were within 400’ laterally of the mountainside regardless of altitude related to TO point.
For example in the U.S. if I TO on a 2500’ cliff and fly out past the edge of it I am legal as long as I stay within 400’ of the cliff face.

Can you show where that is written? I can find that only in the 107 section but not in the Rec section.