What is safe distance from people.

[R.Perry]

A question came up about my operations from the safety people. What is the safe distance horizontally from people not involved in the flight. I didn't know the answer, so I called Dr. Stark at UC Merced, he heads up the UAV department. He said it is 25% of your altitude. Meaning if you are flying at 100 feet, you shouldn't be withing 25 feet horizontally of someone.

One of the Panos I take is very close to a very active street on the college campus. I do that pano at 200 feet and I'm 60 feet from the fence line, meaning I only have 10 feet of horizontal room to work with. I guess he wondered if I was math challenged based on his explanation of how to calculate horizontal safety.

Here is his exact response


My typical recommendation for a safety zone for static, or up/down operations is to keep ¼ of your flight altitude away from busy areas (I can show you the math at some point if you want justification). So if you’re flight altitude is 100 ft, you should keep a safety buffer of around 25 ft around the drone. From the GPS coordinates of the pano, it looks like you have a clearance of roughly 60 ft, so I’d estimate that would be safe up to 240-250 ft altitude. From your imagery, I’d estimate your flight altitude is somewhere around there.

So I think pano 8 is within bounds of safe operations, but certainly close to borderline safe. There are some steps that you can do to reduce risk –

• Try to pick flight times at which pedestrian traffic is minimal – we can predict some time frames based off the class schedules
• Lower your flight altitude or move closer to the building
• Avoid flying during high wind conditions if the wind is blowing to the North West (ie, such that the wind would blow your drone over the bridge). This usually only occurs during the winter – during the summer, the wind is usually blowing to the South East.
• Fly slower to reach the point – keeping it under 10 mph will help minimize the impact zone in the event of a catastrophic failure in motion.

As always, trust your instinct. If something doesn’t feel right, slow down and re-evaluate. If you’d like, I could also join you in the field if you want a second pair of eyes to evaluate safety when you do Pano 8.

Hope this helps,

-- Brandon

Dr. Brandon Stark, Director
UC Center of Excellence on Unmanned Aircraft System Safety
Risk & Safety Solutions
University of California

 

[UAV_Mapper]

I think that this is a prudent response, but it's not a legal response (i.e., the FAA does not have a definition for safety radii). I understand that you're just trying to share your colleague's response, but I wanted to make that note in case someone tried to use it in a legal manner or to think that they are "completely safe" following that rule. Thanks for passing it along.

 

[ansan12001]

I agree with last response.
To further the discussion, although it may seem difficult to know the professional responsibilities in this rapidly changing industry, it actually isn't hard to know how to "fit in" when there is not a specific rule, law or regulation in place.
When you are not sure what to do make a reasonable effort to understand and practice what is standard in the industry. If asked by a attorney in a court of law, this is often the litmus test for your actions. If you are doing something that is within industry standards and you can prove you made an effort to follow the standard, that would be one way to mitigate legal problems.
In other words use good judgement and caution especially when your not sure of the risks.

 

[R.Perry]

As Mapper said, "it isn't law", and I do understand the FAA doesn't give any guidance or regulations regarding a safe radius. I needed a explanation that would satisfy the safety people on the job site, and get an opinion from someone I believe is better versed in drone safety operations than myself.

From a legal standpoint, at least now I have an expert opinion based on his credentials. I'm working on an active construction site and active college at the same time, safety must be my primary concern, the work required is secondary.

 

[BigAl07]

While I think his "estimates" are fairly safe and should "satisfy" your safety people on the job I can tell you one thing for sure... if there is an incident with sUAS striking a person on the ground, the FAA will nail you to the wall for not operating in a SAFE manner. They are well known for giving us just enough guidance (aka ROPE) to allow us to get our tail feathers in a bind (hang ourselves).

Anyone reading this thread needs to take notice that @R.Perry is flying in a very controlled manner and merely ascending and descending straight up and down in a narrow column with no horizontal movement. Any horizontal movement hoses this "estimation of distance".

 

[Florida Drone Supply]

One other thing you can do (and not just because we sell them) is add a parachute to your drone. At that height there is plenty of altitude to dramatically slow the descent of your aircraft and lower the amount of kinetic energy at the point of impact. Some parachutes also have audible buzzers that alert people on the ground to 'look up and see what the noise is' and hopefully move out of the way.

We have them for the M200 series, M600, Phantom and the Mavic 2 version is on the way. We have tested them by intentionally stopping the drones in flight and letting the parachutes guide them to the ground. They work as expected and save a lot of damage to the aircraft - but most importantly help to avoid damage to people and property on the ground.

Parachutes

Protect your drone, yourself, and your surroundings with a parachute. We carry parachutes for drones in case of an operation failure they deploy automatically.

www.floridadronesupply.com

 

[R.Perry]

While I think his "estimates" are fairly safe and should "satisfy" your safety people on the job I can tell you one thing for sure... if there is an incident with sUAS striking a person on the ground, the FAA will nail you to the wall for not operating in a SAFE manner. They are well known for giving us just enough guidance (aka ROPE) to allow us to get our tail feathers in a bind (hang ourselves).

Anyone reading this thread needs to take notice that @R.Perry is flying in a very controlled manner and merely ascending and descending straight up and down in a narrow column with no horizontal movement. Any horizontal movement hoses this "estimation of distance".

You are exactly right, and that is why he recommended a 10 mph approach to the pano position. What I disagree with is the FAA will automatically bring charges of negligence without proof of negligence. All aviation accidents are investigated by the NTSB and yes when it comes to aircraft they go with the FAA findings as well as their own.

There is no formula that will calculate the trajectory of a drone that goes dead stick based on it's weight, altitude, and speed other than for one of a rock the same weight. My normal flight speed is 32 to 35 mph, if I should lose one motor no telling what direction the drone will go before falling out of the sky, all the pilot can do is cut the power and hope for the best.

Part 39 only states that we must not overfly people. If the pilot has lost all control and is not flying over someone and someone is injured then how is that negligence on part of the pilot? People have been inured by drones, and normally it is by someone being reckless.

 

[R.Perry]

Here is examples of what will get you aquainted with the FAA, and some of the stupid thing people do with drones. Notice on the White House the prosecutor set a precedent, he didn't file charges because the pilot had no control of the drone. These are just a few, and how many of those people have been prosecuted?

Drone crashes near the White House
On Monday, January 26, 2015, a drone crash landed on the White House lawn. The White House does have its own specific flight restrictions, but the drone wasn't easy to detect. Immediately after the incident, the White House went into lockdown. The US attorney decided not to charge the drone operator, Shawn Usman, after determining the drone was not under his control at the time of the crash.

Drone cuts off tip of photographer's nose
What started out as goofy holiday promotion ended terribly when a drone crashed into the face of Brooklyn Daily photographer Georgine Benvenuto, clipping the end of her nose and cutting her chin. The drone was a promotion by TGI Fridays called "Mobile Mistletoe," and it carried mistletoe above diners prompting them to kiss.

Drone injures Australian triathlete
At the Geraldton Endure Batavia triathlon in Australia, a drone was being used to photograph competitors when it crashed into triathlete Raija Ogden, causing a minor head wound, which required stitches to close. The drone operator, photographer Warren Abrams, claims that the drone crashed after someone in the audience stole control of it from him.

Drone injures bystanders in Virginia crowd
In the fall of 2013, spectators gathered at the Virginia Motorsports Park for the Great Bull Run, a festival with live music, drinking, a tomato fight, and a bull run similar to the Running of the Bulls in Spain. During the festival, a drone being used to record video crashed into the stands, injuring several people in attendance.

Pilot crashes drone at drone safety demonstration
Back in 2015, Popular Science's Dave Mosher stopped by FOX & Friends to talk about FAA licensing requirements and the safe operation of drones. He proceeded to crash a DJI Phantom 2 Vision+ into a camera operator during the segment.

Drone crashes through 5th story window, hits man in head
A writer in Cape Town, South Africa got a nasty surprise in 2016 when amateur drone pilots crashed a UAV through his fifth story office window and ran it into his head. The writer was subsequently accused of creating a fake video of the account.

 

[R.Perry]

One other thing you can do (and not just because we sell them) is add a parachute to your drone. At that height there is plenty of altitude to dramatically slow the descent of your aircraft and lower the amount of kinetic energy at the point of impact. Some parachutes also have audible buzzers that alert people on the ground to 'look up and see what the noise is' and hopefully move out of the way.

We have them for the M200 series, M600, Phantom and the Mavic 2 version is on the way. We have tested them by intentionally stopping the drones in flight and letting the parachutes guide them to the ground. They work as expected and save a lot of damage to the aircraft - but most importantly help to avoid damage to people and property on the ground.

Parachutes

Protect your drone, yourself, and your surroundings with a parachute. We carry parachutes for drones in case of an operation failure they deploy automatically.

www.floridadronesupply.com

Since we just lost an Inpire 1, still haven't heard what failed. Our branch is considering them. You might want to contact the SF Multivista branch. Actually I would talk to Multivista in Vancouver and see if they will recommend their franchises and contractors use them. Good idea. We use the Inspire 2, and as you know it isn't a light drone.

 

[LUIS MARTINEZ]

You are exactly right, and that is why he recommended a 10 mph approach to the pano position. What I disagree with is the FAA will automatically bring charges of negligence without proof of negligence. All aviation accidents are investigated by the NTSB and yes when it comes to aircraft they go with the FAA findings as well as their own.

There is no formula that will calculate the trajectory of a drone that goes dead stick based on it's weight, altitude, and speed other than for one of a rock the same weight. My normal flight speed is 32 to 35 mph, if I should lose one motor no telling what direction the drone will go before falling out of the sky, all the pilot can do is cut the power and hope for the best.

Part 39 only states that we must not overfly people. If the pilot has lost all control and is not flying over someone and someone is injured then how is that negligence on part of the pilot? People have been inured by drones, and normally it is by someone being reckless.

The doctor said:"(I can show you the math at some point if you want justification) " He must have some mathematical solution to arrive at his recommendation of "to keep ¼ of your flight altitude away from busy areas" . Wonder if he will share it?

 

[R.Perry]

The doctor said:"(I can show you the math at some point if you want justification) " He must have some mathematical solution to arrive at his recommendation of "to keep ¼ of your flight altitude away from busy areas" . Wonder if he will share it?

Since half or our college students today are math challenged, I must assume he was figuring everyone is. Take your altitude, multiply it by .25 and that will give you the radius you should maintain to keep a safe distance from people. That ONLY applies to hovering as we do when we take panos, once you have forward momentum that goes right out the window. As your speed increases that radius primarily in the direction of travel will increase significantly and I haven't done trajectory calcs since I was in college, and that has been a few years ago.
If you are flying a fixed wing aircraft you should know the glide ratio of that aircraft, given altitude, and speed you can easily figure how far you can glide if you lose power.

With our drones we have no such data to work with, they are not like a helicopter that can still have a degree of control upon loss of power, but if our drone goes dead stick you first of alll have no control, secondly if it is moving at the time it's forward energy will carry it it a bit, most likely about like a rock. To calculate the distance based on it's forward speed you would also need to know how much drag the props and body create before you could even guess at a trajectory.

Now if you like playing with numbers, here is the math, and yes I looked it up. What isn't figured in that formula is wind direction, speed and aerodynamics .

position are meters (m).

I think this is one of the reasons the FAA is still scratching their heads on how to come up with some realistic laws.

 

[R.Perry]

Also as stated above, this isn't law, it is only a guideline, but I think it is a reasonable one. As for me, I do try to stay as clear of people as I can.

Luis if you want to chat with Brandon he is an easy guy to get in touch with, and has been very helpful to me including assisting me to get authorization to fly over the active college. He is just one of the people on the college that keeps an eye on me. One Sundays when I do mapping I have a police escort, I guess the campus cops are bored.

 

[LUIS MARTINEZ]

Since half or our college students today are math challenged, I must assume he was figuring everyone is. Take your altitude, multiply it by .25 and that will give you the radius you should maintain to keep a safe distance from people. That ONLY applies to hovering as we do when we take panos, once you have forward momentum that goes right out the window. As your speed increases that radius primarily in the direction of travel will increase significantly and I haven't done trajectory calcs since I was in college, and that has been a few years ago.
If you are flying a fixed wing aircraft you should know the glide ratio of that aircraft, given altitude, and speed you can easily figure how far you can glide if you lose power.

With our drones we have no such data to work with, they are not like a helicopter that can still have a degree of control upon loss of power, but if our drone goes dead stick you first of alll have no control, secondly if it is moving at the time it's forward energy will carry it it a bit, most likely about like a rock. To calculate the distance based on it's forward speed you would also need to know how much drag the props and body create before you could even guess at a trajectory.

Now if you like playing with numbers, here is the math, and yes I looked it up. What isn't figured in that formula is wind direction, speed and aerodynamics .

position are meters (m).

I think this is one of the reasons the FAA is still scratching their heads on how to come up with some realistic laws.

The equation is simple enough but I was wondering where he got the .25 constant in altitude x .25=safe R?

 

[R.Perry]

That's a good question, I don't know, but I will find out. Realistically wind direction and speed should also be a factor, I guess he is using the KISS principle. If you have a 15 mph wind then that radius wouldn't be accurate because down wind direction the radius should be increased. Reality if you can't use a constant, Also as your altitude increased the down wind radius would need to increase. Now the question is, given the original example would the .25 constant be enough even with say a 15 mph wind? Also if I had a 15 mph wind out of the south, I wouldn't be shooting that pano, not that close to the active campus. I'll post a picture so you can see what we are dealing with.

 

[LUIS MARTINEZ]

That's a good question, I don't know, but I will find out. Realistically wind direction and speed should also be a factor, I guess he is using the KISS principle. If you have a 15 mph wind then that radius wouldn't be accurate because down wind direction the radius should be increased. Reality if you can't use a constant, Also as your altitude increased the down wind radius would need to increase. Now the question is, given the original example would the .25 constant be enough even with say a 15 mph wind? Also if I had a 15 mph wind out of the south, I wouldn't be shooting that pano, not that close to the active campus. I'll post a picture so you can see what we are dealing with.

It is still good stuff, I enjoy learning more about UAS trajectory science; it's really a combination of aerodynamics & external ballistics when you get down to it. Many thanks for sharing.

 

[R.Perry]

It is still good stuff, I enjoy learning more about UAS trajectory science; it's really a combination of aerodynamics & external ballistics when you get down to it. Many thanks for sharing.

Here is a resized picture to give you an idea of what I'm dealing with.

 

[Kristina Fowler]

Part 39 only states that we must not overfly people.

I've always wanted clarification/definition of "over". If a drone covers a 14" x 14" area and there are no people standing directly underneath that 14x14 area - even in an otherwise crowded environment - are you legal?

 

[R.Perry]

I've always wanted clarification/definition of "over". If a drone covers a 14" x 14" area and there are no people standing directly underneath that 14x14 area - even in an otherwise crowded environment - are you legal?

Kristina what we are looking for is what is safe. For me, and I'm no expert, if I lose complete control of my drone, and it comes crashing down. I want my drone to be as far away from people as reasonably possible. In my opinion if you are flying in a crowded area, and close to people but not over them and your drone crashes and injures someone I believe the first thing the NTSB and FAA is going to say is you were being negligent. Example say you are flying around a football game at an altitude of 100 feet and there are people within 10 feet of you, I would call that negligent, I wouldn't do it. These are just my opinions, and as stated I'm no expert.

At UC Merced if I flew within ten feet of a student, Mr. Stark would have my fanny. I know the temptation to push the envelope is always there, I also know from experience if you push the envelop long enough one day you will bit the bullet.

There is a saying in the aviation community, "There are old pilots, and there are bold pilots, but there are no old bold pilots." Forty years involved in aviation with no accidents has taught me that saying is true.

ps: my avatar picture was taken in the 70s.

 

[LUIS MARTINEZ]

I've always wanted clarification/definition of "over". If a drone covers a 14" x 14" area and there are no people standing directly underneath that 14x14 area - even in an otherwise crowded environment - are you legal?

I'm assuming you meant 14 feet by 14 feet? The questions you, as PIC, must be satisfied with are...at your chosen altitude and wind conditions, will a power failure cause the UAS to drift outside the 14x14 area (too small IMHO)? Are there measures in place to prevent non participants from wandering under the UAS? If the UAS is moving will momentum cause it to not fall outside your 14x14 area?
Only the PIC can do a risk assessment before each flight.

With the FAA, you are legal until you are not.

 

[Kristina Fowler]

R.Perry - agreed. Certainly, common sense should always prevail. But I always like to take the "grey" out of the equation whenever possible.