400' AGL over natural feature/"structure"

[Meta4]

the lack of a definitive definition of "structure" is an issue. Constructed by whom or what?

You are making this much more difficult that it is.
All you need is a simple dictionary definition like ...

construct​

verb​

past tense: constructed; past participle: constructed​

/kənˈstrʌkt/​

To build or make (something, typically a building, road, or machine).​

It doesn't matter who does the constructing, all that matters is that someone carried out construction.
A structure is something that has been constructed.

Devils Tower can be considered, at least in some aspects, a structure. This paragraph is a structure, as are a sheet of paper and our skeletons.

Do you think the FAA was indicating that you can fly 400 feet above a paragraph or a skeleton?
You are being obtuse to the point of trolling.

It's what the FAA claims a structure to be that is the sticking point here. I can't fathom a reason why a rock spire would be treated differently than a building or broadcast tower.

It's clear that you can't (or won't).
How about talking to the FAA and see if they can convince you of the obvious?

 

[MS Coast]

For sure, fine footage of Devils (the USGS seems to be at odds with apostrophes)

The discussion about whether landforms are structures has begun to sound a bit like a Monty Python skit.

But, on a similarly arcane matter, it seems that your use of an apostrophe is at odds with every other reference to Devils Tower that I see. Apparently it's named for multiple devils rather than just one, and they have no ownership.

 

[Captain Cripple]

It was used as a reference only- perhaps this would’ve been a better image?
View attachment 181282

So if the distance from the sides doesn’t count in the US, how can one legally fly up to or above the top of a vertical tower , building or cliff if it’s over 400’ tall? Take Notch Peak in Utah for example, one side of it is made up of two vertical cliff faces separated by a narrow bench. One of the vertical faces is about 1,500 feet high, and the other is 700 feet high, thus both together make a nearly vertical cliff face over 2,200 feet tall, the tallest in North America. So if the ruling is for height AGL below the drone, I see that one could only legally fly up to the summit only on the sloped sides while maintaining up to 400’ directly above the terrain below the drone all the way up the sloped sides, but not on the vertical cliff face? Correct? If so, I was told the wrong thing regarding cliffs.

LOL, I was about to get the trusty 4Runner packed and ready to go NOW upon learning of Notch Peak, then I hit the interwebs a bit harder and saw pesky drone- and foot-hating terminology such as "wilderness" and "7.5 mile round trip hike with 2600' elevation gain." Oh well. I've spent some time around that wonderful area, yet had never heard of Notch.

It would seem you have spelled it out correctly if one must take that "directly below the drone" part seriously. However, such leaves one wondering how it can be acceptable to fly straight up the side of a skyscraper past 400' (LAANC-free downtown Atlanta would be an example, since the airports are far away, unlike, say Dallas due to DAL), yet a sheer rock face in a remote area is a no-go, and apparently all due to varying interpretations of the word "structure." FTR, I've seen that word used in relation to natural structures ('cuz that's what they are an' all) many times, including by those in relevant fields.

What is the qualitative difference, in terms of aviation safety, between a rock spire and com tower, both shown on sectional charts? Seems like both would be equally unsavory into which to fly a plane and we 107ers should have 400' access to it in a bubble above, to the sides, and BELOW (again....the bridge thing) so long as no other valid regulations prohibit it (NPS, etc.).

 

[Captain Cripple]

Here's my understanding, from what I remember of the Part 107 training and other discussions here.

• A Part 107 certificate allows you to fly up to 400' directly above a structure and within 400' laterally from the structure. That allowance doesn't apply to landforms; they aren't structures. It also is not applicable within controlled airspace under a LAANC authorization.
  
  
• The 400' altitude limit is referenced to the ground immediately below the drone. There is no allowance for exceeding 400' AGL when within 400' of another landform.

I can see why someone would think that, but I can't find any documentation that, according to the FAA, a landform is not a structure and I can find many examples of landforms being referred to as structures elsewhere. So, it's unclear.

The 400' controlled airspace LAANC deal is very clear, even though that took me a few minutes to find a definitive answer on.

 

[Captain Cripple]

Welcome! That’s a fascinating question, and you're right—FAA guidance on defining "structures" is murky. Given Part 107's wording, your interpretation seems reasonable, but an official FAA ruling would clarify things. Safe flying!

Thank you, Saul. It's a pleasure to be here.

I concur. It's a fascinating question that's unclear in critical aspects. Common sense resoundingly bellows that, for aviation safety purposes, a landform and structure MUST be treated equally, but ain't nobody with a gummint job managed to write that down yet and....LOL....the people who be 'posta do it may have done gotten canned

Best, and thanks again for the welcome.

 

[Captain Cripple]

Where is the murk? Landforms are not structures.

What aspect of the Part 107 regulations regarding flights over and near structures needs clarification?

The murk is to be found in a lack of confirmation that landforms are not structures AND the repeated use of the word "structure" in relation to landforms by people who engage landforms for a living or scientific study.

Often, in regulations, we get operational definitions of critical terms. I'm having a hard time finding one for "structure" and definitively excludes landforms. I see no such thing in 107. Perhaps it's there and I went out to lunch and didn't see it, but we sure couldn't find it and those in my camp are rather competent researchers.

And, common sense points toward landforms and anthro-structures being treated similarly RE: aviation safety.

 

[MS Coast]

And, common sense points toward landforms and anthro-structures being treated similarly RE: aviation safety.

As a Part 61 pilot in the past, I was personally very happy to have the FAA treat mountains and 1000' tall antennas differently, especially on sectional charts.

"Structure" is certainly used by some to represent landforms and even things like fish habitat. But, I've never encountered anyone flying manned aircraft or drones that referred to mountains, hills, valleys, or other landforms as structures. "Structure" has always been understood to be a human-created potential obstacle. (This thread being the sole exception.)

The situations where interpreting the Part 107 400' allowance over structures to include landforms would make a difference in drone flights are rare. I've never encountered one. I'll continue to see structures as man-made things and never fly in circumstances where I might have to have this structure discussion with the FAA.

 

[Captain Cripple]

You are making this much more difficult that it is.
All you need is a simple dictionary definition like ...

construct​

verb​

past tense: constructed; past participle: constructed​

/kənˈstrʌkt/​

To build or make (something, typically a building, road, or machine).​

I disagree. There is ambiguity. Who is the builder? Does it /they have to be mortal humans?

How is "construct" used in FAA regulations? What is the direct relevance of that word to this matter? Structures are not necessarily constructed by mortal humans, according to how I've seen the term used while researching this, and the FAA has perhaps not seen fit to make it clear.

It doesn't matter who does the constructing, all that matters is that someone carried out construction.
A structure is something that has been constructed.

Do you think the FAA was indicating that you can fly 400 feet above a paragraph or a skeleton?

LOL. Geological forces construct. Is there a reason for a rock spire and radio tower to be considered qualitatively different for aviation safety purposes.

The skeleton point was to illustrate the wide range of meaning the word "structure" can have, and if a skeleton or paragraph is a structure, perhaps Ship Rock is also one, especially given the FAA's apparent reluctance to clearly tell us it ain't.

Now, if the FAA has made it clear and we somehow didn't catch it, my bad, but given that we're now this far into the thread and ain't nobody pasted the relevant lowdown straight outta Trigger's mouth, methinks that ain't the case.

You are being obtuse to the point of trolling.

Dang! Well, aren't you a dear?!?! I gotta confess, I kinda liked Saul's welcome and characterization a bit better. No. Like. Button. For. You. Exclamation. Point.

I can't recall anyone calling me obtuse in the 52 or so years of my life I can clearly recall. Therefore, no matter what else happens, I will always have a special connection with Meta4. You were my first

Trolling? Hardly. My posts are earnest, in good faith, and the issue was deemed "fascinating" by at least one other user. I find the obtuse and trolling claim outrageous, but, I'm not a very nervous person, see, so you do you, Sport.

Feel free to post a definitive answer, should you encounter such info.

It's clear that you can't (or won't).

Can't or won't WHAT? Ya feelin' OK out there, sir? Scanning upward, I can't find any text to which I can relate that utterance.

How about talking to the FAA and see if they can convince you of the obvious?

Heck, Hoss, howzabout I talk to 'em and see if'n I can convince them of the obvious, like how a clear answer to this matter should be in the books.

From my end, "obvious" don't cut it - it's at least somewhat subjective." I'm looking for explicit, documented regulation, and there most certainly should be one.

Feel better

 

[Captain Cripple]

The discussion about whether landforms are structures has begun to sound a bit like a Monty Python skit.

But, on a similarly arcane matter, it seems that your use of an apostrophe is at odds with every other reference to Devils Tower that I see. Apparently it's named for multiple devils rather than just one, and they have no ownership.

The fabulous gentlemen from Python, who changed the world by bringing desperately needed and overdue irreverence, relied heavily on semantics for their humor.

And, here we are.

Many (and many of them directly associated with the world of landforms) find them to be structures.

Yes, that initial apostrophe was in error. The USGS wanted to keep things free of apostrophes. Dang cursed genitive s abusers! In case you've not noticed, I'm detail-oriented, so I cry foul.

It appears that we're dealing with a single devil in possessive form here, but, like with that whole 400' structure thing.......

it's ambiguous.

 

[Captain Cripple]

"As long as you are within 400 feet near (laterally or above) a building or hill, including mountains, Devils Tower or table top mesas, you can fly up to 400’ above its highest point as long as you are within 400’ distance from its side or top."

That's correct in the United Kingdom, but not in the United States. See post #10.

Howdy, again. It seems to be correct in the UK, but unclear in the USA. A definitive answer is proving elusive.

And.........what of that bridge thing?

 

[MS Coast]

Yes, that initial apostrophe was in error. The USGS wanted to keep things free of apostrophes. Dang cursed genitive s abusers! In case you've not noticed, I'm detail-oriented, so I cry foul.

You may well be right about the USGS avoiding apostrophes. Pikes Peak offers a supporting example. Further investigation might reveal additional examples, and perhaps an official policy statement. There's probably a style guide lurking in the USGS's Geographic Names Information System (GNIS.

In any case, I think we might agree that the insidious and growing use of 's to form plurals is a certain sign of the decline of western civilization.

As for that bridge that might be legal to fly over but not under, be sure to set your RTH altitude and lost signal behavior as you would flying beneath a forest canopy. Don't program the drone to climb into a manmade structure or the canopy structure.

(I've noticed that this sort of discussion seems to arise on days when it's either raining, very cold, or blowing 20+ kts.)

 

[Captain Cripple]

You may well be right about the USGS avoiding apostrophes. Pikes Peak offers a supporting example. Further investigation might reveal additional examples, and perhaps an official policy statement. There's probably a style guide lurking in the USGS's Geographic Names Information System (GNIS.

In any case, I think we might agree that the insidious and growing use of 's to form plurals is a certain sign of the decline of western civilization.

As for that bridge that might be legal to fly over but not under, be sure to set your RTH altitude and lost signal behavior as you would flying beneath a forest canopy. Don't program the drone to climb into a manmade structure or the canopy structure.

(I've noticed that this sort of discussion seems to arise on days when it's either raining, very cold, or blowing 20+ kts.)

Check on the 20+ kts wind over here.

In one of the late, great Neil Peart's travel books (Far and Away, I think it was) he writes of visiting Martha's Vineyard, one of but a handful of places in the USA allowed to use their apostrophe in USGS land.

I've long been on the soapbox regarding the misuse of apostrophes in possessives. How....obtuse (LOL!) and oblivious can someone be, considering the correct answer is in front of their face hundreds of times a week. Ever seen a bag of Frito's, a song by The Door's, or a Chicago Bear's game?

No.

Interestingly, some will put apostrophes on some of the plural nouns, but not others, appearing to spread their bets as if playing roulette or such.

Yeah, copy big time on that RTH thing. I once watched a guy crash his fancy new aircraft into the underside of a bridge while demonstrating the function and mansplaining to his old lady, who was not real big on him buying the drone to start with. The look on his face as it chattered up a brief ruckus, then crashed into the creek was priceless.

Then, he shifted into overFAFO tried to start a fight with my camp 'cuz we were laughing so hard and came sort of close to getting, well, uh....shot.

I sure hope a definitive answer to the subject of this thread will make itself known. That fact that it hasn't yet is itself interesting. Until I'm informed otherwise, I'll legally FPV dive every thousand foot rock wall that's accessible and not on NPS, etc. turf.

 

[hank970]

The fabulous gentlemen from Python, who changed the world by bringing desperately needed and overdue irreverence, relied heavily on semantics for their humor.

And, here we are.

Many (and many of them directly associated with the world of landforms) find them to be structures.

Yes, that initial apostrophe was in error. The USGS wanted to keep things free of apostrophes. Dang cursed genitive s abusers! In case you've not noticed, I'm detail-oriented, so I cry foul.

It appears that we're dealing with a single devil in possessive form here, but, like with that whole 400' structure thing.......

it's ambiguous.

The USGS is not responsible for the naming of geographic features or the manner in which they're named and spelled. In fact, the governing body in the United States responsible for the formal identification of all geographic places and features is the U.S. Board on Geographic Names, established in 1890. Because the Board comprises representatives of multiple federal agencies, the USGS may play a membership role from time to time. By convention, and contrary to normal rules of standardized usage, the Board specifies that all geographic entities with possessive names be spelled without apostrophes. Thus, we have Pikes Peak in Colorado, Scottys Castle in California, Clingmans Dome in North Carolina, Harpers Ferry in West Virginia, and the Clarks Fork of the Yellowstone River in Wyoming and Montana, among many others. I don't know the rationale behind that spelling decision, but that's the way it is.

 

[mavic3usa]

^I also think you can change the order of the name of the geographic feature in lieu of using a possessive apostrophe; for example instead of America's Gulf you can just call it Gulf of America. Honestly, it doesn't take a whole lot to name a geographic feature; just do it.

 

[hank970]

^I also think you can change the order of the name of the geographic feature in lieu of using a possessive apostrophe; for example instead of America's Gulf you can just call it Gulf of America. Honestly, it doesn't take a whole lot to name a geographic feature; just do it.

Of course, folks are free to call geographic features whatever they want. There's a little rise behind my home that we call Gazebo Hill. But such informal names won't ever appear on official maps unless someone petitions the Board on Geographic Names and makes a case that the name be officially adopted. Gulf of America? I think it should be named the Gulf of Hank because I was stationed on its shores at Pensacola NAS as a Marine Aviation Cadet (MARCAD) many decades ago. That said, it wouldn't surprise me in the least if, flying in the face of centuries of common international understanding, there were to be considerable pressure placed on the Board on Geographic Names to change its name to Gulf of America. You know, just because...

Now, back to the original discussion. I hope there isn't anyone here who thinks that a Redwood tree is a structure.

 

[Captain Cripple]

Good catch. I was aware of the Board, but opted to go with the tidy and recognizable acronym USGS 'cuz they apparently absorbed the BGN at some point. You are quite correct.

There are, as I noted, a few exceptions to the un-apostrophe standard.

Now for my good catch - it's actually a punctuation, not a spelling issue

 

[Captain Cripple]

Of course, folks are free to call geographic features whatever they want. There's a little rise behind my home that we call Gazebo Hill. But such informal names won't ever appear on official maps unless someone petitions the Board on Geographic Names and makes a case that the name be officially adopted. Gulf of America? I think it should be named the Gulf of Hank because I was stationed on its shores at Pensacola NAS as a Marine Aviation Cadet (MARCAD) many decades ago. That said, it wouldn't surprise me in the least if, flying in the face of centuries of common international understanding, there were to be considerable pressure placed on the Board on Geographic Names to change its name to Gulf of America. You know, just because...

Now, back to the original discussion. I hope there isn't anyone here who thinks that a Redwood tree is a structure.

Me, myself, and I, the three of us are stickin' with Gulf of Mexico. Our alternate is Gulf of Bill Ward (legendary Black Sabbath drummer and singer). Just because.....

Sorry for the buzzkill, but yes, there is. I'm willing to consider a redwood a tree a structure. I just wish the FAA would make it clear one way or another.

Yes, a tree is considered a structure, specifically a natural structure, as it has a defined form with a trunk, branches, and roots that work together to support the plant and allow it to grow tall, making it a complex biological structure.

 

[Captain Cripple]

As a Part 61 pilot in the past, I was personally very happy to have the FAA treat mountains and 1000' tall antennas differently, especially on sectional charts.

"Structure" is certainly used by some to represent landforms and even things like fish habitat. But, I've never encountered anyone flying manned aircraft or drones that referred to mountains, hills, valleys, or other landforms as structures. "Structure" has always been understood to be a human-created potential obstacle. (This thread being the sole exception.)

The situations where interpreting the Part 107 400' allowance over structures to include landforms would make a difference in drone flights are rare. I've never encountered one. I'll continue to see structures as man-made things and never fly in circumstances where I might have to have this structure discussion with the FAA.

Should they be treated differently regarding Part 107 UAV flights and if so, why?

I'll hesitate to refer to a valley as a structure, but Devils Tower or Ship Rock? Thems be structures.

The most thrilling, by far, drone flights ever I've beheld involve this topic. I shan't give up 1500+ foot dives on desolate land unless I see it codified. I remain baffled about why this was not made excruciatingly clear and explicit in the regs.

Thanks for your input here.

 

[Meta4]

I remain baffled about why this was not made excruciatingly clear and explicit in the regs.

It is ...except to those who want to troll.

 

[MS Coast]

Isn't it time to shut this thread down?