Max Altitude Over Tree Canopy?


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Hi all, got this question from a student and curious what you think:

Re:  In our training we learned that it was possible to fly drones above certain structures, like towers, even if they go above the 400’ max level for drones. Does this apply to other natural structures like trees? For example, if my tree canopy is at 200’, does that mean that I can fly my drone up to 600’ AGL?

Here's the rule:

Quote

 

§ 107.51 Operating limitations for small unmanned aircraft.

A remote pilot in command and the person manipulating the flight controls of the small unmanned aircraft system must comply with all of the following operating limitations when operating a small unmanned aircraft system:

(a) The groundspeed of the small unmanned aircraft may not exceed 87 knots (100
miles per hour).

(b) The altitude of the small unmanned aircraft cannot be higher than 400 feet
above ground level, unless the small unmanned aircraft:

(1) Is flown within a 400-foot radius of a structure; and

(2) Does not fly higher than 400 feet above the structure’s immediate
uppermost limit.

 

And here's a defined list of FAA-defined structure types: https://www.faa.gov/air_traffic/flight_info/aeronav/obst_data/structuretypes/

I'm inclined to say a "tree canopy" doesn't qualify as a structure...what do you think?

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I suspect that FAA's answer would be a resounding NO.  Not for any particular reason but for the fact that a man manmade structure has a fixed height - it's not going to change.  A tree, well that's something different.  Where I live, the tree canopy is a major issue, so if there's enough of an interest I will call the FSDO for my area/state and ask.  The answer I expect is that AGL means GROUND!

 

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10 hours ago, Alan Perlman said:

Hi all, got this question from a student and curious what you think:

Re:  In our training we learned that it was possible to fly drones above certain structures, like towers, even if they go above the 400’ max level for drones. Does this apply to other natural structures like trees? For example, if my tree canopy is at 200’, does that mean that I can fly my drone up to 600’ AGL?

Here's the rule:

And here's a defined list of FAA-defined structure types: https://www.faa.gov/air_traffic/flight_info/aeronav/obst_data/structuretypes/

I'm inclined to say a "tree canopy" doesn't qualify as a structure...what do you think?

I know this is late but the answer is 400FT AGL is the cap. My latest CoA stated that in controlled airspace, the UAS facilities map at https://faa.maps.arcgis.com/apps/webappviewer/index.html?id=9c2e4406710048e19806ebf6a06754ad is now an absolute value and may not be exceeded. They specifically call out that "This altitude is an absolute value and it shall not be added to the height of any building structures." So for controlled airspace only, there is no regards given to structures any more. I am wondering if this is a regional thing or applies to everyone in the NAS... 

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I can’t imagine the FAA would carve out a regional implementation of the rule.  

Regarding the height above trees, I believe the reason for allowing a drone to fly 400’ above a structure is becuase manned aviation is expected to stay 500’ from any man made object or person.  That doesn’t apply to trees, unless there’s some one climbing it I guess..

So if everyone follows the rules there’s still separation between aircraft.

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  • 2 years later...
On 3/26/2018 at 10:05 AM, R Martin said:

I know this is late but the answer is 400FT AGL is the cap. My latest CoA stated that in controlled airspace, the UAS facilities map at https://faa.maps.arcgis.com/apps/webappviewer/index.html?id=9c2e4406710048e19806ebf6a06754ad is now an absolute value and may not be exceeded. They specifically call out that "This altitude is an absolute value and it shall not be added to the height of any building structures." So for controlled airspace only, there is no regards given to structures any more. I am wondering if this is a regional thing or applies to everyone in the NAS... 

Under current regulations the 400FT AGL cap is absolute for recreational operators.  However under 14 CFR part 107 you can fly above and within a 400-foot radius of a "structure".  See section 5.10 of https://www.faa.gov/documentlibrary/media/advisory_circular/ac_107-2.pdf

The vague part of this definition is around the meaning of the word "structure".  FAA does not define the word "structure" anywhere that I could find, but does in many places refer to structures and trees separately, hence the assumed definition of a "structure" does not include trees which would mean even under part 107 you cannot fly 400 feet above trees.

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