FAA Category 2 and 3 Explored... What is 11ft/lbs of kinetic energy???

[Xitor]

The other issue is that it would not fall under any category, it's uncategorized just like most of the current drones DJI makes including the Air 2s, mini, mini 2, mini 3 pro, etc etc.

So in regards to the rule of flying over open air assembly, even with a prop guard. Due to being uncategorized drones, they still can't fly over people according to the FAA period. DJI has to submit approval for each model to be categorized and so far the only approval they got was for Remote ID, not for categorization.

In short, doesn't matter how much force a Mavic Air 2 would cause, because you won't be able to fly over anyways without that categorization officially approved and labeled.

Ugh, why in the world would you create the categories of drones to classify them, then say "you don't fit in any of them"? Always assumed (I know bad thing to do) that since I was less than 55 pounds surely I would fall into category 2 or 3. Thanks for your response here, almost posted a similar question, but see its already answered. Can only hope they get categorized at some point.

 

[karlblessing]

Ugh, why in the world would you create the categories of drones to classify them, then say "you don't fit in any of them"? Always assumed (I know bad thing to do) that since I was less than 55 pounds surely I would fall into category 2 or 3. Thanks for your response here, almost posted a similar question, but see its already answered. Can only hope they get categorized at some point.

It's annoying but I'm hoping that when they do start getting category listings that current production models can at least get a sticker from the manufacturer if they are identical to the categorized ones.

 

[RandomTask]

So I'm trying to understand what kinetic energy of 11 ft/lbs and 25 ft/lbs.... Here's what I can't up with for a Mavic Air 2 at 1.3lbs... (I'm not a physicist btw).

11 ft/lbs is 14.9 joules. 1.3lbs at a velocity of 16mph is 15.1 joules.

25 ft/lbs is 33.9 joules. 1.3lbs at a velocity of 24mph is 33.9 joules.

So... Crashing into a person at 16mph is a Category 2 event, yes?

And crashing into someone at >16 but
But is the FAA talking about a freefall event?
In which case, 1.3lbs falling from 400ft reaches 109mph, which would be 700 joules or 516 ft/lbs.
Obviously this is a freefall and a drone has a significant amount of drag so it would fall slower (sorry, I don't have data for how fast a MA2 freefalls).

Pilots, please chime in.

I'm late to the party here, but a couple of points worth mentioning...

Please note the FAA's wording, to wit:
"Will not cause injury to a human being that is equivalent to or greater than the severity of injury caused by a transfer of 11 foot-pounds of kinetic energy upon impact from a rigid object;"

This DOES NOT say "The drone must not hit a person with more than 11 ft lbs". It says it:

must not cause more damage than a *rigid object* hitting with 11 foot pounds.

This is not a trivial difference. If a drone hits you, does it instantly stop dead, without bouncing away or snapping apart? Probably not. Extremely unlikely for it to just hit you and drop in place having transferred all its energy to you. Both of those things (breakage and bouncing or tumbling away) mean energy was not transferred to you.

A 1" steel ball weighs 2.36 ounces. Moving at 69fps (47mph) would be carrying 10.91 foot pounds, and probably transfer just about all of it if it hit you straight on. Having that hit you in the head is going to be much more likely to cause injury than a 16 mph Mavic. THAT impact is what you should be comparing against. The mavic is going to hit, twist, tumble, flex possibly break. All of which means it is absorbing the energy rather than you.

Similarly when we start talking mini 3 / 4 (and possibly 2? others?)...the regulation on cat 1 says

• Contain no exposed rotating parts that would cause lacerations.

"Would". Not "could". Yes they have exposed rotating parts...but people have actually tested this and you have to really work at getting cut by the blades from one of these. It's absolutely possible that it *could* cause lacerations, but it's rather unlikely. People who have managed to cut themselves (or strawberries) have eeeeaaaased the soft skin (or strawberry) into the blades. It cut up the strawberry but barely nicked the hand. In the case of a "collision" I think it's extremely unlikely to draw blood from the blades. Biggest danger is to eyes.

 

[Felix le Chat]

Perhaps. But they only just now put class 1 on the Mavic 3 classic over in EU (which isn't the same thing as category 1 in the US). So they feel behind but I don't know if autel etc are doing any better about it.

US category #1 is based on the same premise as EU class #1, the bureaucrats of Europe just got there ahead of their US cousins. British bureaucrats don't recognise the class system (there's a massive ironic joke in that statement) as they are trying to lump everything from the mini all the way up to octacopter cine-lifters into one category: Drone. By doing that, they can remove all weight based exemptions and regulate everything with a single document.

 

[RandomTask]

I'm late to the party here, but a couple of points worth mentioning...

Please note the FAA's wording, to wit:
"Will not cause injury to a human being that is equivalent to or greater than the severity of injury caused by a transfer of 11 foot-pounds of kinetic energy upon impact from a rigid object;"

This DOES NOT say "The drone must not hit a person with more than 11 ft lbs". It says it:

must not cause more damage than a *rigid object* hitting with 11 foot pounds.

This is not a trivial difference. If a drone hits you, does it instantly stop dead, without bouncing away or snapping apart? Probably not. Extremely unlikely for it to just hit you and drop in place having transferred all its energy to you. Both of those things (breakage and bouncing or tumbling away) mean energy was not transferred to you.

A 1" steel ball weighs 2.36 ounces. Moving at 69fps (47mph) would be carrying 10.91 foot pounds, and probably transfer just about all of it if it hit you straight on. Having that hit you in the head is going to be much more likely to cause injury than a 16 mph Mavic. THAT impact is what you should be comparing against. The mavic is going to hit, twist, tumble, flex possibly break. All of which means it is absorbing the energy rather than you.

Similarly when we start talking mini 3 / 4 (and possibly 2? others?)...the regulation on cat 1 says

• Contain no exposed rotating parts that would cause lacerations.

"Would". Not "could". Yes they have exposed rotating parts...but people have actually tested this and you have to really work at getting cut by the blades from one of these. It's absolutely possible that it *could* cause lacerations, but it's rather unlikely. People who have managed to cut themselves (or strawberries) have eeeeaaaased the soft skin (or strawberry) into the blades. It cut up the strawberry but barely nicked the hand. In the case of a "collision" I think it's extremely unlikely to draw blood from the blades. Biggest danger is to eyes.

Replying to myself here because I just did a renewal on my 107..and noted something interesting.

In _several_ spots, there were references to Category restrictions for OOP. In _none_ of the questions did it mention the "rotating parts / lacerations" bit for Cat1. Only on 2/3. Something changed? Found it interesting is all. There were at least 3-4 spots where I would've expected it.

 

[karlblessing]

US category #1 is based on the same premise as EU class #1, the bureaucrats of Europe just got there ahead of their US cousins. British bureaucrats don't recognise the class system (there's a massive ironic joke in that statement) as they are trying to lump everything from the mini all the way up to octacopter cine-lifters into one category: Drone. By doing that, they can remove all weight based exemptions and regulate everything with a single document.

Category 1 in the US is sub-250g, which a class 1 Mavic 3 is definitely not.

 

[Felix le Chat]

So I'm trying to understand what kinetic energy of 11 ft/lbs and 25 ft/lbs.... Here's what I can't up with for a Mavic Air 2 at 1.3lbs... (I'm not a physicist btw).

11 ft/lbs is 14.9 joules. 1.3lbs at a velocity of 16mph is 15.1 joules.

25 ft/lbs is 33.9 joules. 1.3lbs at a velocity of 24mph is 33.9 joules.

So... Crashing into a person at 16mph is a Category 2 event, yes?

And crashing into someone at >16 but
But is the FAA talking about a freefall event?
In which case, 1.3lbs falling from 400ft reaches 109mph, which would be 700 joules or 516 ft/lbs.
Obviously this is a freefall and a drone has a significant amount of drag so it would fall slower (sorry, I don't have data for how fast a MA2 freefalls).

Pilots, please chime in.

In Britain, the maximum legally allowed muzzle power of an off-the-shelf air rifle is 12ft/lbs.... although the business end of a Mavic is a lot bigger than the business end of a .22 calibre pellet. If you were daft enough to hold your hand approximately 5 feet in front of the barrel when someone pulled the trigger, you'd have an object lesson in what 11ft/lbs of kinetic force felt like.

 

[MS Coast]

• Contain no exposed rotating parts that would cause lacerations.

"Would". Not "could". Yes they have exposed rotating parts...but people have actually tested this and you have to really work at getting cut by the blades from one of these. It's absolutely possible that it *could* cause lacerations, but it's rather unlikely. People who have managed to cut themselves (or strawberries) have eeeeaaaased the soft skin (or strawberry) into the blades. It cut up the strawberry but barely nicked the hand. In the case of a "collision" I think it's extremely unlikely to draw blood from the blades. Biggest danger is to eyes.

The photographs and reports posted here and elsewhere of lacerations sustained while hand catching drones argue otherwise.

 

[RandomTask]

The photographs and reports posted here and elsewhere of lacerations sustained while hand catching drones argue otherwise.

Agreed.

To be honest/fair, I mis-read -- I was talking about the _mini_ being difficult (not impossible) to cause big bloody wounds, not the _mavic_.

 

[MS Coast]

Agreed.

To be honest/fair, I mis-read -- I was talking about the _mini_ being difficult (not impossible) to cause big bloody wounds, not the _mavic_.

Even the Mini series drones have caused significant lacerations.

The Pilot Institute did some testing with a Mini 2 and concluded that without prop guards, it can create lacerations to humans and does not meet the Category 1 requirement.

- test

How to Legally Fly Drones Over People and Moving Vehicles - Pilot Institute - blog post summarizing tests and conclusions regarding flight over people.

Bottom line: A Mini series drone can qualify as a Category 1 drone only with propeller guards installed and a substantially lighter battery in place of the normal battery to keep the gross weight at or below 250 grams.

 

[bitsbytes]

Even the Mini series drones have caused significant lacerations.

The Pilot Institute did some testing with a Mini 2 and concluded that without prop guards, it can create lacerations to humans and does not meet the Category 1 requirement.

- test

How to Legally Fly Drones Over People and Moving Vehicles - Pilot Institute - blog post summarizing tests and conclusions regarding flight over people.

Bottom line: A Mini series drone can qualify as a Category 1 drone only with propeller guards installed and a substantially lighter battery in place of the normal battery to keep the gross weight at or below 250 grams.

PI as well as vast majorities of people in these forums and elsewhere seem to keep butchering the language of the rule - the language is *"would"* cause lacerations, not "could" or "can" cause lacerations.

"Would cause lacerations" implies a case where it is more likely than not for lacerations to be created on contact with human skin, and is impossible to demonstrate in their limited trial as compared to the conclusion of the testing segment that essentially claims "the fake skin got slightly indented by 0.5mm on one of our several tests therefore you need prop guards."

Minor skin abrasions and/or contusions, combined with a minor risk of shallow lacerations (which is essentially the result of all of the other tests) do not reach the level of "[more likely than not] would cause lacerations."