A couple thoughts:

> Your landing point is 7 ft (2 m) from a 164 ft (50 m)-tall building — taller than drones may fly, so we keep at least 80 ft (25 m) from it.

The numbers are from just clicking a random spot, but I'm kind of confused about how you're interpreting the regulations. In the US, the maximum allowable altitude is 400 feet AGL per § 107.51(b), albeit with a structure exemption for Part 107 pilots. Within a 400 foot radius around a structure, you can fly 400 feet above said structure's maximum height. That drops down to 400 feet AGL the moment you go beyond that radius, however.

Setting aside both the math error with the building height and the structure exemption, what's the basis for the exclusion zone that's being referenced? Granted, you absolutely want horizontal separation near buildings to account for winds that can easily slam a drone into a window, but the error message could imply that your 80 foot clearance is a nonexistent regulatory rule. I'm guessing that's just a conservative safety margin to make flight planning easier, but you should explicitly identify it as such so as to avoid ambiguity or the implication that it's a prescriptive FAA regulation. There's a reason why clarity and precision are so critical in pretty much any aviation document.

Anyhow, it's an interesting concept, one that I could see it being useful in planning but I'd double check some of the altitude logic. I'd also add references to error messages that point to the relevant regulations that trigger the warnings.

0. https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F...

1. https://pilotinstitute.com/drone-altitute/

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unwind 2 days ago | parent | next [-]

What math error with the building's height? Assuming it's what you quoted, 164 ft converts to 49.9872 m so "50 m" seems excellent as the value to present?

	▲	Bluestrike2 a day ago \| parent [-]
		I'm assuming that the application first compares building heights to the nominal 400-foot AGL altitude limit: 400-164 equals 236 feet of vertical airspace in which it's legal to fly even before you consider the structure exemption that would permit 564 foot AGL within a 400-foot radius of the building. Calling it a math error was a bit of a misnomer on my part. I'm still not quite sure what calculation would have a marked location like that as a "no-go," and re-reading the error messages doesn't really clarify the logic. When it says "too tall to clear safely from there" I'm reading that as the building is too tall and thus you can't fly above it, but that's clearly wrong on two levels. Likewise, the building height + 400 feet was still well below the floors of the relevant Class B and Class C airspace shelves around SFO and OAK. Best guess is that the 80 foot exclusion zone around a building the program applies is probably to blame. There are some other problems I noticed, but I'll send those to the OP via the feedback form on the site.

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nimitmehra 2 days ago | parent | prev [-]

Thank you. You are right. The 80ft buffer is our own buffer not FAA buffer. The message should say so, I will change it.

"Taller than drones may fly" is wrong for 164ft building. What tripped it is, at that spot the local LAANC facility map ceiling which is below 400ft and on top of that, we have kept 50ft clearance over buildings. I would change it so the full calculation is shown.

About the exception for §107.51(b) - I kept the stricter 400 feet AGL cap because of how data is collected. Currently, the building heights are based on OpenStreetMap (some are estimated from floor count from the ground) and Data SF 2010 LiDAR. If the height is wrong or approximated, it may say Go for a flight that is over the legal limit.

I will cite which regulation applies for each route. That is a good idea I will add it.

	▲	dylan604 3 hours ago \| parent [-]
		One could go crazy trying to understand the inner workings that caused the reply to be flagged/dead. A user makes a Show HN, another user asks a direction question, the OP user makes a reply. How does that get flagged when it's a direct answer the question. Maddening. So yeah, I vouched