
Drone hobbyists find flaws in “close call” reports to FAA from other aircraft - Varcht
http://www.usatoday.com/story/news/2015/09/13/drone-reports-faa-close-call-near-miss-academy-model-aeronautics-/72064388/?AID=10709313&PID=3836173&SID=iekr385peb0004o400dth
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fnordfnordfnord
I want to know more about this drone that was supposedly pestering an aircraft
during firefighting operations. 10,000 ft altitude is quite high; if it was a
quad-copter type thing, I've got my doubts that it could make it to that
altitude at all, much less maintain that altitude for any length of time. I'm
going to assume that anything flying higher than ~15,000 ft is a military
drone, and the FAA using these particular sightings to cast aspersions at
private individuals is dishonest. Including incidents involving drones
operated by the police is also pretty sketchy. Media are parroting this crap
uncritically; I hope more of them find some gumption and ask a question or
two. I can see where drones are _potentially_ a problem, especially
considering that they are only getting better/cheaper; but this sham-press
release thing from the FAA appears to be scaremongering and it deserves
ridicule.

Links to both the FAA's press release and the AMA's response in this AMA blog
post.

[http://amablog.modelaircraft.org/amagov/2015/09/14/ama-
respo...](http://amablog.modelaircraft.org/amagov/2015/09/14/ama-responds-to-
the-faas-drone-sighting-report/)

~~~
votingprawn
There is some confusion in this particular case stemming from the difference
between altitude above sea level and above ground level.

The UAV in question was spotted at ~10,000ft above sea level, but it was only
about 800-900ft above the local ground level at the time.

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fnordfnordfnord
There is no confusion. I assumed 10,000 ft above sea level. Starting at 9,000
ft doesn't help much. The air is quite thin at 10,000 ft; many small general
aviation aircraft have difficulty reaching that altitude. Here is a YT video
showing a few minutes of someone's drone flight allegedly at that altitude. It
doesn't appear to me that sustained flight for any reasonable duration is
possible with that particular drone, nor do I expect any/many other drones to
perform much better.

[https://www.youtube.com/watch?v=WnnlAS5Zzfg](https://www.youtube.com/watch?v=WnnlAS5Zzfg)

~~~
votingprawn
Apologies, your phrasing "make it to that altitude" made me think otherwise!

Multi-rotors using BLDC motors cannot really be compared to small general
aviation aircraft with infernal combustion engines.

"Reasonable duration" is a nebulous phrase. Some of the airframe
configurations we use here couldn't manage more than about 10 minutes at
100ft, whereas others could quite happily carry a gopro at 10,000ft for 10
minutes (assuming it didn't have to climb from sea level!)

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fnordfnordfnord
re: my phrasing, I did assume that the drone pilot in question started from a
much lower (unknown to me) altitude.

>Multi-rotors using BLDC motors cannot really be

It's got nothing to do with the type of motor or fuel.

>"Reasonably duration" is a nebulous phrase. So

So is "quite happily carry". I'll admit that it appears that it's not
impossible for such a flight, but I don't agree that any drone is "happily
carrying" anything at that altitude.

~~~
votingprawn
Well I gave a payload (gopro, 350-400grams with gimbal) and a duration (10
minutes), I'm not sure what else to say! The aircraft was completely
controllable with no memorable handling differences apart from a very slightly
reduced response to high thrust demands, but as we fly our platforms for
stability rather than speed it wasn't something that we really noticed.

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ChuckMcM
The thing is, at 10,000' you have to move a lot more air in order to maintain
the thrust necessary to stay at altitude. This additional RPM requires more
current and that cuts into your battery life. It would be an interesting
comparison to run a number of drones at 10K' to see how they held up.

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Vexs
There was a post on reddit/r/multicopter a while ago of prop thrust at
different air pressures with the same current. It's pretty much exactly what
you're asking for.

[https://i.imgur.com/Z5toIVm.jpg](https://i.imgur.com/Z5toIVm.jpg)

Assuming air pressure at 10000 ft is ~69kpa, and sea level is ~100kpa, there
really doesnt appear to be much of a difference, except for medium-sized
props, which had very interesting thrust outputs- gaining efficiency at low
rpm and loosing a lot at high rpm.

Anyway, point being is a 250 class quad could pretty easily fly at 10000 feet.
Not particularly well, but considering 1:4 (or even 1:8) thrust ratios arent
uncommon with 250 class quads they could still pull it off.

Now, idk about bigger quads like the phantom/iris, their props have quite
different geometries which probably act quite differently.

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headShrinker
At 10000ft, pressure is around 30kpa. Using the data you provided in the link
and assuming a quad weighs any were around 600-800grams with camera, the multi
rotor will be flighting at near 100% power. Sustained flight time would be
very limited.

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votingprawn
> At 10000ft, pressure is around 30kpa.

Do you mind if I ask where you are getting that pressure value from?

The ICAO Standard Atmosphere gives a value of 70kPa for 10,000ft.

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dirktheman
Sigh. I'm a "drone hobbyist" myself, although I mostly refer to the hobby as
"RC model flying". Nothing new, because the RC flying hobby has been around
for decades.

Part of me applauds the stricter rules. It's just so easy for some knucklehead
to buy a quadcopter from China and fly it around the White House or an airport
or over someone's backyard. Unfortunately, these people destroy the hobby,
giving it a bad name.

On the other hand, the rules we have had for decades (don't fly near airports
or restricted zones, don't fly too high, don't fly over crowds, etc.) are
perfectly fine and reasonable. We don't need stricter rules and regulations,
we need common sense from drone pilots.

Secretly I hope that drones are really a fad, and the interest will fade away.
That leaves the hobby for the real enthousiasts.

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TazeTSchnitzel
"Common sense" isn't common. Lay down clear rules and get people to follow
them.

~~~
masklinn
Yup. If you expect a nebulous and undefined "common sense" to prevail after
your hobby has entered its eternal september what you'll end up getting is a
severe crackdown when shit inevitably hits the fan.

"Common sense" is mostly social norms (usually starts out as "hard-earned
wisdom" until the culture forgets how it was acquired), when there's a huge
continuous influx of new participants the "old culture" can't keep up, neither
can its "common sense". Doubly so when a hobby lends itself to nefarious uses
and mindless fuckups as much as drones do.

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wheaties
As someone taking off from a runway the other day and having to actually dodge
a stupid camera tied to balloons, we don't always report all that stuff. I,
for one, welcome the rules. I also understand that not everyone will follow
them. Welcome to the world.

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fnordfnordfnord
That stupid camera tied to balloons wasn't by chance a permitted-in-advance
activity was it? We have that at my local airport. A few times per year a prof
from a nearby uni sends a balloon up mostly for the benefit of his students.
You ought to hear the Saturday morning FBO free-coffee-drinkers club whine
about the inconvenience of it. All GA pilots may not always report everything,
but there are a few who report everything they see and everything they imagine
they saw.

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jonnycowboy
Usually the balloon flyers must post a NOTAM (notice to air men) which pilots
request from the local tower prior to takeoff or landing.

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paublyrne
If there is misreporting for political reasons, that is unfortunate. How and
where drones can be operated is a real concern and will become only more and
more of an issue as they become cheaper, better, and more common.

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rasz_pl
TLDR: the big “close call” list consist of every mere mention of a word Drone
by a pilot, not the actual near misses.

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peterwwillis
Near miss? It's a near hit! A collision is a near miss!

 _sound of explosions_

"Aw, will you look at that, Dave. They nearly missed."

"Yes. But not quite!"

\-- George Carlin

~~~
mikeash
I greatly enjoy that bit, but it's also totally wrong. "Near" is not the same
as "nearly." It's "near" as opposed to "far." It's a miss which is near.

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peterwwillis
I don't buy it. What if the miss wasn't near? Would it be a far miss? An
average miss? What exactly is the point at which you go from colliding to a
near miss, to any other kind of miss? It's redundant language.

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mikeash
Sure, if you miss by a huge amount it could be a "far miss" or a "distant
miss" or similar.

The point where you go from colliding to a near miss is the point where the
two things don't touch. There's no exact point where you go from a near miss
to a regular sort of miss, since it's not a precision term.

~~~
peterwwillis
But they don't far miss or distant miss. They weren't aiming for each other.
"Near miss" is the only way you would ever refer to planes almost colliding
with the word "miss", so the "near" part is redundant. They missed. If you
wanted to say they were close, you could say they almost hit, which is not
only more accurate, it's not redundant, because you can't take out either word
and still express the same idea.

This isn't just to be pedantic; there's lots of redundant or incorrect
language out there which Carlin talks about at length.

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dragonwriter
> there's lots of redundant or incorrect language out there which Carlin talks
> about at length.

While Carlin -- as comedians often do -- used the manner in which natural
language idioms are irregular as the basis for some of his humor, the
irregularity of natural language idioms is not incorrectness. It may be
aesthetically displeasing to people who have a strong preference for
regularity -- a preference which is probably overrepresented in the HN
audience -- but that's a different issue.

~~~
peterwwillis
I'm not concerned with aesthetics. I'm concerned with incorrect language which
leads to incorrect thinking. I could talk at length about a single word and
how its misinterpretation by a huge subculture leads to bad decision making,
but let's just say words are very important.

