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250g Question - Why?

PacificSkyDreamn

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Would anyone know the basis for the FAA selecting 250g as the threshold for regulations. The Mini 3 Pro's performance specs are almost identical to my Air 2 - one has to get RID next year the other doesn't. Seems the FAA picked 250g years ago when drones where much bigger and little palm size drone where indoor/backyard toys. Can't a Mini 3 be misused or pose the same threat as an Air 2? As drones continue to get small and more powerful from a performance standpoint, could the FAA lower the weight limit, say to 200g or 150g, and then RID would apply to them?

Not suggesting they lower it, just wondering how difficult would be for the FAA to do, especially if drone manufactures like DJI are able to deploy RID via a firmware/software update to existing drones.
 
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Empire Drone

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It has something to do with the kinetic energy of the drone in freefall (how hard it's going to hit someone or something on the ground). I remember it seeing how they came up with 250 grams when they announced it but don't remember why they specifically chose that number.
 
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YVRGUY

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A 250 g M3P free falling from 400’ 🆚 the increasing satellite 🛰 and rocket 🚀 debris we’re already experiencing …I can live with 250 g drone hitting me just fine thank you 😊.

Satellite and rocket debris coming into our atmosphere and falling to earth I can safely say, is 6-10 times that of a speeding bullet and it doesn’t have to be greater than 1 gram to cause severe bodily harm.

So, on the “Chicken Little” scale…a 250 g free falling M3P shouldn’t bring out the ‘sky is falling’ alarm. But, falling piece/pieces of space junk should. The worst thing is that what goes up can’t always be predicted where it will go down.

The 250 g regulation is just fine, and doesn’t need changing…at least in my opinion. Just watch out for falling rocket 🚀 boosters 😵‍💫👍
 
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offtheback

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A 250 g M3P free falling from 400’ 🆚 the increasing satellite 🛰 and rocket 🚀 debris we’re already experiencing …I can live with 250 g drone hitting me just fine thank you 😊.

Satellite and rocket debris coming into our atmosphere and falling to earth I can safely say, is 6-10 times that of a speeding bullet and it doesn’t have to be greater than 1 gram to cause severe bodily harm.

So, on the “Chicken Little” scale…a 250 g free falling M3P shouldn’t bring out the ‘sky is falling’ alarm. But, falling piece/pieces of space junk should. The worst thing is that what goes up can’t always be predicted where it will go down.

The 250 g regulation is just fine, and doesn’t need changing…at least in my opinion. Just watch out for falling rocket 🚀 boosters 😵‍💫👍
Remember Skylab?
 

Rang624

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FAA is all about safety. If the drone below 250g start posing as a threat (ie people start misusing them), then yes, you can bet the FAA will lower the limit. As it is if you use your drone, reguardless of size, for a part 107 use, it has to be registered.
 

YVRGUY

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Remember Skylab?
Yes I do…1979. Australia 🇦🇺 got a free light show for their 150th anniversary 🎆. Funny, Skylab was devised to never fall back into our atmosphere, but, it did.

The chances of more debris coming down due to the increasing amount of debris being sent up there 👆is growing. Some will not completely burn up on descent.

Currently, I don’t feel the 250 g free falling drone is as big a concern…being responsible /safe pilots is. 👍
 

Ex Coelis

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Would anyone know the basis for the FAA selecting 250g as the threshold for regulations. The Mini 3 Pro's performance specs are almost identical to my Air 2 - one has to get RID next year the other doesn't. Seems the FAA picked 250g years ago when drones where much bigger and little palm size drone where indoor/backyard toys. Can't a Mini 3 be misused or pose the same threat as an Air 2? As drones continue to get small and more powerful from a performance standpoint, could the FAA lower the weight limit, say to 200g or 150g, and then RID would apply to them?

Not suggesting they lower it, just wondering how difficult would be for the FAA to do, especially if drone manufactures like DJI are able to deploy RID via a firmware/software update to existing drones.
It’s not just FAA; it’s a generally accepted concept internationally.
250 grams at terminal velocity is unlikely to crack a cranium?! 😁
 

JimCunn

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What's the terminal velocity of a 250 gram drone?
If 45 mph, we are talking about 37 ft pounds which would be a noticible thump on the noggin.
 

Zbip57

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Would anyone know the basis for the FAA selecting 250g as the threshold for regulations.

Here is a copy of the November 2015 report to the FAA from the Unmanned Aircraft Systems (UAS) Registration Task Force (RTF) Aviation Rulemaking Committee (ARC) which spawned the 250 gram number. It is interesting reading.

They calculated that the risk of fatality from a falling 250g object to a person on the ground is:
"4.7x10 -8, or less than 1 ground fatality for every 20,000,000 flight hours of an sUAS"

The report includes this interesting quote:
"Some members of the task force questioned why sUAS risk level would ever be required to exceed the current general aviation risk level of 5x10 -5."

Note: They calculated the risk of fatality from a 250g UAS falling on your head is 1000 times less than the risk presented by general aviation.

Read the report: www.hsdl.org/?view&did=788722
 

BbqJoe

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I find it rather interesting that they worry about the terminal velocity of 250 grams falling from a height of 400 feet, when there's so much bigger concerns, such as a 217 million gram (empty 747) falling on your head from 30,000 feet.
 

Zbip57

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I find it rather interesting that they worry about the terminal velocity of 250 grams falling from a height of 400 feet,[...]

It's worse than that. They assumed a worst case of it being dropped from 500 feet (not 400) falling into a densely packed urban environment of 10,000 people per square mile.

So obviously for most of us flying in less populated areas and at a legal height of 400' AGL or less, the actual risk will be orders of magnitude smaller.

The report notes:
"(For these purposes, we have used population density numbers reflecting a relatively densely packed
urban environment
. We have done so despite the fact that sUAS operations are prohibited over
unprotected persons not connected to the operation).
"
 

BbqJoe

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It's worse than that. They assumed a worst case of it being dropped from 500 feet (not 400) falling into a densely packed urban environment of 10,000 people per square mile.

So obviously for most of us flying in less populated areas and at a legal height of 400' AGL or less, the actual risk will be orders of magnitude smaller.

The report notes:
"(For these purposes, we have used population density numbers reflecting a relatively densely packed
urban environment
. We have done so despite the fact that sUAS operations are prohibited over
unprotected persons not connected to the operation).
"
It all kind of reminds me of the letters I sometimes receive from The Department of Redundancy Department.
 

Meta4

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It's worse than that. They assumed a worst case of it being dropped from 500 feet (not 400)
A falling drone reaches terminal velocity in just a few seconds.
500 or 400 ft wouldn't make any difference to the speed of freefall impact.
 

Zbip57

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A falling drone reaches terminal velocity in just a few seconds.
500 or 400 ft wouldn't make any difference to the speed of freefall impact.
True that.

I just mentioned it because they went out of their way in the report to note that flying over unprotected persons not connected to the operation is already prohibited, but we'll use that scenario anyway because it suits us to do so. And yet they totally ignored, with no mention, that flying at 500' AGL is similarly prohibited, but we'll go ahead and use that too.

The whole point is that their hypothetical scenario is what they felt was a worst case, and their calculations founded on those questionable assumptions directly resulted in the 250 gram threshold that's now used almost universally around the world, except for 200gram in Japan, or Europe which insists a more meaningful threshold for determining a need for registration, rather than weight, is based on whether or not the UAS carries a camera.

Having thus determined that the risk of fatality from a 250gram UAS falling from 500' into a densely packed urban environment is already 1000 times safer than general aviation, how would they ever now convince anyone that sub-250 gram drones present any sort of significant risk worthy of more stringent regulation?
 

MS Coast

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Having thus determined that the risk of fatality from a 250gram UAS falling from 500' into a densely packed urban environment is already 1000 times safer than general aviation, how would they ever now convince anyone that sub-250 gram drones present any sort of significant risk worthy of more stringent regulation?

Unfortunately, I think you're underestimating the capacity for fear in the general public. Fact and reality have little to do with what most people fear. Shark bites are high on the list, even for people who seldom swim and then only in fresh water. Food items a week beyond the "best by" date terrify some folks. Soon after the onset of the Covid pandemic, a few twitter and Facebook posts plunged the nation into a panicked toilet paper buying frenzy that became a national shortage.

Sadly, one Super Bowl or Indy 500 fan killed by a falling drone might be all it takes to spawn a change in the regulations.
 
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