The Enemy Within… NIAS

The sUAS industry is constantly under scrutiny from those who may not understand what sUAS do.  It’s true that there are indeed some drone incidents that should not occur,  yet they are fairly rare and as groups such as the AMA, FAA, and many blog and social media posts continue to educate the general public, these incidents are now more closely scrutinized, rather than amplified.

In the Southern Nevada region, we have an enemy from within the UAS community, a state agency known as the Nevada Institute for Autonomous Systems, or “NIAS.” They are the fox within the henhouse, harnessing fear and falsehood to bring attention to their operation and develop revenue at the expense of commercial drone operators. By way of local opinion, most in the Nevada UAS ecosystem have felt NIAS has been counter-productive and harmful stemming from their first days managed by Bowhead, which became ArrowData, now somewhat separate from NIAS as yet another corporation that is (to all accounts) the sole beneficiary of NIAS existence.

Imagine being a small business in Nevada, with a state agency competing with your business operations, quotes to clients, training offerings, etc? It’s not a fair playing field.

NIAS,  a “non-profit corporation, leads the growth of the Nevada Autonomous Aerial Vehicle Industry through business teaming relationships, collaboration with primary research institutions, and helping enhance the UAS industry knowledge base in order to attract new and permanent business within the State of Nevada,” the fact of the matter is, NIAS’ lack of awareness, practice, involvement in, and relationship with the Nevada sUAS industry, its pilots, practitioners, and professionals is entirely empty and absent. From my perspective:

  • NIAS has failed at the Nevada test site.
  • NIAS has failed as a training facilitator.
  • NIAS has failed at business development for Nevada.
  • NIAS has failed at UTM.
  • NIAS has failed in creating local and regional relationships with commercial operators. They have only one beneficiary.
  • NIAS has failed at bringing opportunity to local enterprise.
  • NIAS has failed at bringing college programs to fruition.
  • NIAS has failed their local “Teammates.”
  • NIAS is consistently ridiculed by local professionals.

Now, NIAS has turned to Counter-UAS as their next area of “expertise.” They are again moving down the road of another failure.

A sergeant once asked me during a training exercise; “What is the most dangerous in any operation/scene? The man who doesn’t know what he is doing.”

My experience with NIAS ranges from a “beginner’s guide to drone safety”  (since been removed from the web) to utter incompetence in a field of varied UAS operations. NIAS threatened to sue a private enterprise for the use of the words “Center of Excellence” that was started more than a year prior to NIAS decision shift direction and create their own COE. The “beginning drone” article was  filled with false statements regarding drone use across the USA. Authored by NIAS, the article was not only inaccurate/false, it appeared to have been authored by an 8 year old with terrible grammar.

Moreover, why was NIAS, as being dedicated to commercial drone operations, authoring blogposts for children?

The FAA recommends tools other than their own B4UFly, as it is not up to date, is not designed for commercial operations. Per comments in the article, what sUAS can actually *reach* Class Alpha airspace, Dr. Walach? In that same vein, it’s unfortunate NIAS seemingly doesn’t understand “TFR” vs “SFRA,” and where is the National Capital anyway? And what sUAS carries a “black box recorder, particularly a consumer-type unit from a local big box store?

NIAS does not know what they’re doing. 

We recently observed NIAS Director Dr. Chris Walach “deputizing in the name of the State of Nevada,’ a large crowd as “visual observers’ in the event of an incident or flight overhead ” (Click link to see video). Further, he instructed people to “jump over bleachers in the event of a drone flying towards the audience.  This is not legal per FAA FAR 107.39. (video credit; sUASNews)

At this same event, NIAS was not prepared to put into place standard requirements for any unmanned airfield. No first aid kit, no fire suppression, no salt for lithium polymer batteries, and no wind direction indicator. The director of NIAS embarrassed himself before a professional group when he didn’t know what an anemometer is, and didn’t know the difference between an anemometer and what he consistently referred to as a “Wind-o-meter,” much to the amusement of the pilots at the well-attended event with manufacturers from around the globe. NIAS had agreed to provide all of the above equipment during multiple planning meetings prior to the event.

Pilots were unhappy that there was no wind direction indicator , tossing dirt into the air to determine direction. Eventually a makeshift indicator was created by one of the attendees using a broomstick, duct tape, and a bit of plastic sheeting.  

At this same event, NIAS insisted that Nevada could pass her own laws regarding airspace over Nevada paying no heed to the recently, previously released FAA statement.

Not long after, published an article about the malfeasance of NIAS as relates to UTM in the USA.  It has also been suggested by vendors that NIAS mis-appropriated funds from various government programs.

And then the below news story hit our community on 11.30.18

I happened to be alongside the FAA ASI’s that took this call, and we spoke at length about it (after they’d ramped our operation).

First, 500′ of separation is enormous in that area. Second, there are several operators in Las Vegas with Bravo/Night operations waivers. At the reported altitude of ~2500 MSL, the unmanned aircraft was likely to have been operating at ~2200 MSL. The helicopter on approach, is at an approximate altitude of 2800-2900 MSL (suggested altitude of 3000 MSL) which means if the helicopter pilot is absolutely correct, the highest the drone was flying is 2400 MSL, but more likely in the 2200 MSL range. Las Vegas altitude is 2001MSL. In other words, the drone was definitely below 400′ AGL, and more likely 250-300 AGL, where there is a NOTAM in that area on that evening.

It’s difficult to estimate altitude from above or below the aircraft, manned or not.

Further, there is no “1 mile around the airport that is a no-fly zone,” not on any chart, nor any state or federal regulation (not to mention that the reported area is greater than one mile from the airport, and certainly not “at the end of the runway” as Walach suggests. The FAA is currently investigating. The FAA does not comment on active investigations, hence the lack of commentary in the television news report. However, it is *highly* unlikely the FAA will investigate this call beyond checking for NOTAMs.

The upper left purple circles indicate NOTAMS filed by drone pilots on the date of this non-incident. Note how far they are from the ends of the runways purported by Walach? Both are very near the Strip at the north end, slightly south of Sahara at the north, and west of I15 at Flamingo on the south.

“If it bleeds, it leads…”

Understanding the reporter’s responsibility to “If it bleeds, it leads,” it’s hard to hold the news station accountable for doing their job, even if it is a sensationlization and misses actual safety concerns.  One cannot blame the reporter for not knowing what questions to ask of the FAA.

“Safety” isn’t the point of this blog post…

Mine are the words and opinion of an exceptionally disappointed tax-paying professional in the sUAS industry, one of many who underwent the process of becoming a NIAS “Teammate,” one who has unsuccessfully attempted to professionally engage NIAS and its resources.

State-funded agency NIAS consistently acts in a diametrically-opposed manner to basic unmanned aviation operation safety, security, operations, and lacks information of the general industry.

NIAS is detrimental to the professional operators of commercial sUAS operations in the state of Nevada, using fear, mis-information, and made-up lies to create a revenue stream for their operation as counter-UAS consultants.

NIAS frequently comments on operations, yet is not participant of any operation.  NIAS frequently is asked for advice about UAS operations in Southern Nevada while not participating in operations. They do not attend trade shows, they do not attend UAS community gatherings. NIAS does not interface with Public Safety groups, yet they have announced a “Public Safety Center of Excellence”, not having done their due diligence to understand that a Nevada Drone Center Of Excellence for Public Safety organization already existed, operated by one of NIAS registered TeamMates. When NIAS became aware of the previously existing Center of Excellence, their first response (and current response) is to threaten legal action against those who work full-time as public safety agents, volunteers, supporters, and officers.

NIAS has lost most of their state funding, and questionably is transferring from state funded to a 501(c) operation. In short, the state has funded a failed organization that harms legitimate UAS businesses, so that the state agency can now become a competitor to legitimate, existing businesses that have built their operations without state funding, without state assistance, even in spite of NIAS’ consistently damaging approach to UAS in Nevada.  Imagine a state-funded agency, begging for money via GoFundMe.

How is it that a state agency is being permitted to transfer to a 501(c) in the first place?
From my perspective as a taxpayer, NIAS and their government cronies have conspired to create a business, initially funded by taxpayers that has never turned a profit, and now that same state-funded, failed business, is being supported while it converts to a 501(c), taking donations to make payroll.

How is this legal? Perhaps our AG Adam Laxalt should spend some time looking into the matter?

If you’ve reached this far, congratulations; it’s a long read. So please continue and hear this message; Nevada is a terrific state for sUAS operations, testing, and development. Nevada has unique industry and landscape making it ideal for sUAS testing 12 months out of the year, with harsh heat and harsher cold.  We are in a unique environment for manufacturing, military, commercial, and recreational uses for sUAS. It can be legitimately argued that consistent use of UAS began in this state, and we should honor that legacy through the continued embrace, encouragement, and development of robotic flight, ground, and even water unmanned systems.

Unfortunately, NIAS is not the vehicle that currently has the staff, knowledge, education, involvement, nor acumen for development of autonomous robotic systems in the state of Nevada. From my perspective, NIAS is an enemy within the UAS community, an armchair quarterback who has never observed nor played in a football game. Due to incompetence, NIAS has thrown away literally millions of taxpayer dollars to zero benefit of the citizens, businesses, and municipalities in this state.

The State (as do all states) needs a robotics management office of some sort.

The State of Nevada would better be served by an individual or an organization that is intimately involved with airports, law enforcement, fire, commercial operators, oil/gas, infrastructure, FAA, FCC, the casinos, and others who benefit from both commercial uses of UAS and C-UAS.  This state needs a strong Unmanned Robotics Division Director with a few passionate, capable persons working beneath him/her in concert with the Governor’s office, legislature, DPS, DOT, and other relevant state agencies. And no, I hold no interest in being that person.

Patrick Egan of said it well when he wrote; ““Nevada Institute for Autonomous Systems falsely conducts civil operations as Public Aircraft Operations, misrepresent themselves as a government-owned corporation, misrepresent themselves as a government agency, misrepresent themselves as the FAA-Designated UAS Test Site and have circumvented §40125(a)(2) and §40125(a)(41) (D) to gain a competitive advantage over civil entities operating under Part 107 while being paid or reimbursed for these services.”

In that vein, why, after some of these challenges to NIAS operations, did all the meeting notes “vanish” from the GOED website?

GOED, please do the right thing; NIAS should be either shuttered, or better, reorganized with people who know the UAS  manufacturers, software engineers, FAA, NASA, Lockheed, Boeing developers, users, and industry verticals who benefit from the continued development of sUAS technology, partnerships, and implementation in to the ground, waters, and skies of the State of Nevada.

**These are my opinions, limited to my own person based on long experience in government and aviation, and ethical business practices. My employer nor agencies that contract my expertise are not expected to share my views/opinions. **

HUFFINGTON POST IS WRONG and here’s the proof…

Yesterday the Huffington Post authored a story about a drone breaking through a window, hitting an interface designer in the head, and giving him a headache.


Mr. David Perel may be an interface designer, but he is also something more, something nefarious in the eyes of the UAV/Drone community.

He’s unbelievable in his claims of being a victim.

And the Huffington Post is helping to elevate his prevarication to the detriment of UAV operators/pilots.


The mere shape of this “break” is the first clue to the hoax. It’s obvious the impact point to the window came from inside the window and not outside. Next, the shape is too “cartoon-like” and contrived.  For example, notice the two “fang” shapes hanging down. How did the drone pass through that section without either scratching the heck out of the drone, and more importantly, without breaking any props? Anyone who has tipped a DJI Phantom on its side knows the stock plastic props will break with only the motor velocity, yet we’re expected to believe that static glass didn’t break the props?

Note the round patttern of the break. The battery on the Phantom would have had to have been the primary impact point in order to create this sort of patterning, and it is physically impossible for the battery to have struck the window. The arms, props, and landing gear all would have hit first, and these are all extremely fragile (Ask any DJI owner; there are thousands of photos of broken props/landing gear.)

This DJI Phantom crashed into the ground at slow speed, yet suffered more damage than the alleged Perel incident being spread across the news.
Additionally, the size of the window provides a tensile strength, one that there simply is no way a  2lb piece of fragile plastic could have broken. Small surfaces are stronger than large suspended surfaces.

The glass pattern on the floor also indicates a hoax. Notice that the photos and video don’t show the shatter pattern? Shattered glass patterning is well-researched, well documented, and this doesnt fit.


Objects on the desk provide clues; they’ve moved between photos being taken. Admittedly, this is a less obvious clue, as objects may have been moved around when taking stills.


This is the view just prior to impact. Somehow, the camera shifts from a forward face with a landing gear/leg in the shot, to a rear-ward face with the same landing gear in the shot, but manages to somehow capture an arm/prop, too. None of the movement is consistent with an out-of-control drone. Why do we never see Mr. Perel, the alleged victim, in any of the rotating video shots? After all, it did strike him hard enough in the head that he’d experienced “a headache” that was needed significant recovery time. Where are the pictures of the cuts or bruises? These are flying Cuisinarts, after all.



None of these points add up. At 00:13 into the video, there is an obvious edit point. Watch the video at quarter speed. Why would there be an edit point in a “this is the whole story” video, particularly at the point of impact?


The article quotes Perel as saying there was a GoPro camera on the drone, and he removed the memory card before looking for the owner (this was later changed both on Huffington Post and on the victim’s Instagram page).


Mr. Perel certainly knows what a GoPro camera looks like. His YouTube page is filled with GoPro videos, so he apparently has one or access to one.
Yet this Phantom has no GoPro on it. It has a factory-built Vision camera that looks nothing like a GoPro. He says in his instagram post that “he removed the card from the GoPro.”

DJI Phantom 2 Vision Camera, as seen in this photo.

The GoPro looks quite different than the DJI camera








Note that the Phantom has no damage other than a half-broken prop. The hoax would be more believable had the very fragile landing gear, and equally fragile gimbal been at least damaged. Every hobby store that sells DJI has at least a few replacement landing sets around, as these thin bits of plastic frequently break or crack during normal landings. One company, PolarPro, even makes a landing gear/gimbal protector, due to the fragility.


PolarPro Gimbal Guard/landing support

Mr. Perel is likely also desperate for web views to please his sponsors (most of us are). Until this video hit, his videos have suffered from low numbers of views that don’t quite support the claim to being the great advertiser his buiness webpage suggests. He claims to have millions of eyeballs on him every month. From where? What evidence supports this claim?

DroneFakeDavidPerel Views.jpg

Mr. Perel claims on his business page that he is a good advertising partner.


I believe Mr. Perel has other motivations to gain eyeballs on his site; a couple of clicks on his website demonstrate he’s looking for money to achieve a dream. he needs money for his endeavors and doesn’t mind reaching out to get it from others. What better way to draw eyeballs to his cause than a pathetic plea for attention?
Poor guy.
He has a headache.
Perhaps he was up all night creating the hoax with friends?
His twitter account demonstrates that he knows how to edit and process video, supposedly like a pro.

For a would-be sports star that has “millions of viewers” it’s surprising that only 28 people gave $4K in a month. Apparently these millions of eyeballs aren’t people with money?

Mr. Perel’s own Twitter account demonstrates that on-line views are his source of income. The 8,800 followers compared to his 31,000 tweets suggest his marketing schemes aren’t so effecDroneFake15tive and are a far cry from the “millions” he claims to be able to deliver to advertisers.

My speculation is that Mr. Perel is needful of attention and created a very well-done hoax that Huffington Post (and other publications) didn’t research prior to publishing an article that on the surface appears to be a real story. This disappoints me because I’ve generally considered Huffington Post to be a higher-grade, more truthful and accurate publication that digs into stories prior to publishing. From my chair, their credibility took a huge hit with this story and HP should take a huge hit with anyone reading this blog post. It’s difficult to blame anyone for trying something new to draw page views.

Congrats Mr. Perel, you’ve gained your Warhol-ian 15 minutes of fame. I only hope it’s not at the expense of South African UAV regulations becoming more restrictive.

Shame on you Huffington Post; you’ve deeply disappointed me, and I’m sure many others in publishing/perpetuating this clever, but easily dismantled hoax that may prove harmful to the UAV/Drone industry worldwide.


[edit] Mr. Perel deleted his Instagram pictures and claims of injury after I chatted a link to this blog.  I have emailed the constabulary, CAA, and other authorities in South Africa to alert them to the fraud/hoax, in hopes that no authority misunderstands this situation and takes no action against drones due to Mr. Perel’s publicity stunt.






The media are all about small Unmanned Aerial Vehicles (sUAV) these days, perhaps better known as “drones.” Drones add significant value to our lives and will become more important as we move forward into the future. However, with all technologies come great responsibilities. One of those responsibilities is how we operate our personal UAV/drones.

Last week in Clarendon, Texas, a newbie drone owner/operator decided to check out an antelope. The “pilot” is a self-admitted newbie, claiming he only has “20 or so flights” on his newly acquired device and perhaps that’s the reason for his short-sighted approach in flying his device close to a wild animal.


There certainly is nothing wrong with wanting to capture the antelope in a natural setting. In fact, some would be a little jealous of such terrific subjects to film. Where this endeavor went wrong is when the drone owner decided to try to film the animal at eye-level and up close.


The antelope makes an attempt to run away and the drone operator chose to chase the animal at high speed. The antelope turns and wants to check out the drone. Due to the erratic flight of the drone/poor piloting, the antelope perceives a threat and attacked the drone before running off.



The drone doesn’t suffer much damage, but what about the antelope?

Veterinarians all over the world have made comment about the dangers propellers bring to dogs-noses. There have been a few cases of eye-loss, at least three of them infants who have been injured by propellers. In this article, several prop injuries can be seen.


It’s not as though these flying Cuisinarts are entirely face-friendly. The face shown here was cut with the same model drone as used in the antelope video. With this in mind, I approached the owner of the drone. He felt strongly that an animal’s face is tough enough to handle this sort of incident and that it couldn’t possibly harm the animal in any way.


Regardless of the drone operator’s opinion, it stands to reason that even small drones like the popular white DJI Phantom can do damage to eyes and other soft tissues whether human or beast, as evidenced by hundreds of photographs around the web.

The particular drone I was using wouldn’t break the skin on my hand…” Travis Higgins, drone pilot

This little guy has permanently lost his eye to a DJI Phantom propeller, the same model drone seen in this antelope video.


I can’t particularly fault the drone owner for being defensive; he truly doesn’t know what he doesn’t know, but hopefully the many posts on his YouTube account have informed him that he made a mistake and it won’t be repeated. YouTube certainly provides some good learning opportunities. There are many websites, pages, and community groups where new drone operators can gain knowledge and awareness of how to best manage their drone use.

But what about other drone owners? Do they “get it?” 

If recent news articles ranging from flying a drone into the side of the Empire State Building, to a drone owner attempting to get close to presidential candidate Hillary Clinton (just before he crashed it into a building as well), it would seem many drone owners aren’t understanding the impact and risk that the excitement of drones bring to the community. In this particular case, the operator continually referred to himself as a “licensed pilot who knows the FAA rules.” There are no FAA rules that apply here; common sense should prevail. Yet he’s convinced that “since he’s an FAA-licensed pilot, what he’s doing is OK.

What might have the drone operator done to not endanger the antelope while still getting great footage?

  • Learn to fly more gracefully/skillfully before putting the drone into the personal space of people or animals. The FAA recommendations are that drones are never closer than 100′ to “non-involved individuals.”

  • Never fly at an altitude or distance that is in close proximity of living beings. In this case, 10′ up would have sufficed; the image could have been post-processed in editing to crop/zoom in on the subject). Again, a topic related to learning more about the device, its camera system, and the technology.

  • Be respectful of the animal. If it runs off it likely is scared and it’s possible the drone could induce the animal to self-injury. Keep your distance. Every year, Yellowstone Park has a percentage of visitors injured or killed because they can’t recognize this rule. They, like the drone pilot in this video, think the animals are like pets and can be gotten close to.


A final comment; the owner of this drone and video claimed his flight was not commercial as he wasn’t being paid to shoot it, but does claim the video is intended for a wildlife conservation video. Money does not need to exchange hands to be considered “commercial” by the FAA. Indeed, if this video is anything more than a couple of buddies having some fun and capturing some hobby footage, it becomes “commercial.” Given that this particular video has received attention from CBS and ABC requesting use for remuneration, and that it’s receiving coins from YouTube for play, it falls into the category of “commercial.” Any commercial video requires a 333 exemption from the FAA, and without it, it is subject to very expensive fines. Be very aware of this, as the FAA and Transport Canada are watching YouTube and social media sites, and several individuals have been charged with using drones for commercial use, although that may not have been the drone operator’s original intent.

Drone owners are very concerned about potential rules, regulations, and controls placed by the government on our technology. Unfortunately, these sorts of videos cause enough uproar that the government truly has little choice but to try to protect us from ourselves.

Be responsible. Fly within the recommendations of the FAA or your local authorities. Understand that not everyone wants to be part of your drone video.  Be considerate, be safe.

[the owner of the video has now disabled comments after receiving many negative comments about the flight]

Why *I* Don’t Catch my Drone

Catching a Drone

Recently I was asked “When do you choose to catch your drone vs landing your drone?

Catching a drone in midflight seems to be a badge of honor amongst some drone pilots and the reasoning behind it is baffling. It’s “so easy to do” there are even videos that teach drone operators how to catch their drone.

They have a number of arguments in favor of doing so.

I don’t want to risk my UAV hitting the ground.” “Dirt gets into the props when it’s taking off or landing.” “It looks really cool to people watching, and it shows I’m a pro when I catch my drone.”

On Facebook I once made a comment regarding the safety aspect of drone-catching and was promptly rebuffed with “If you can’t catch your drone, you don’t know how to fly” was the leading theme in the long string of derisive commentary that followed. I *can* catch my drone, just as I *can* play tag with an angry bull in a corral (and have done so).

A previous article entitled “Understanding Turbulence,” discusses how rotors and lee-winds can unpredictably affect UAV/drone flight. A human body is an obstacle to wind and the body is capable of diverting rotor wash or create a sink space. While being able to catch a drone mid-flight is certainly ego-supportive, it simply is unsafe for oneself and bystanders.




Here are a few injuries from around the web, demonstrating a varying degree of injuries by small UAV propellers. Some propellers are nylon-encased plastic. Others are carbon-fiber (CF). CF props are the most dangerous of all as they have no give, and are very sharp on the edges, providing for faster flight and more precise control.

Small drone injury

This is a relatively small cut from a prop, incurred while catching a drone mid-flight. An arrogant UAV operator commented “He didn’t know how to fly.” Perhaps the injured person knows how to fly; an unpredictable wind caught his vehicle and caused it to tilt?

A drone selfie and catch went wrong when the props fell into the sink created by a body obstructing air.


Some people simply don’t learn the first time. There are those that count these scars as “badges of honor.” One might call them scarlet letters of stupidity. This person has experience in cutting himself.

Larger drone injury

With a drone loosely in hand and the motors spinning down,the drone may fall away from or towards the body, catching a bicep or forearm.

Pre-stitch cut

This is a similar injury. The injured man was holding his drone by the landing skids and it “pulled away and then towards him” as the quadcopter attempted to self-balance. Nine stitches later, he regretted catching and holding the vehicle. At least the CF blades made for neat and clean slices.

Drone Stitches

Having a flying Cuisinart at arms-length or less simply isn’t a good idea for a variety of reasons. At arms-length is entirely too close to the face and neck.

A reporter for the Brooklyn Daily was struck by a drone, cutting her nose and chin.


Ultimately, the crew at Mythbusters (they love UAV/Drones and use them in production of their show) did a segment on the potential lethality of drones. Perhaps a bit extreme, one cannot miss their point.

Latin pop-star Enrique Eglasias likely has lost significant sensitivity in his hand due to attempting to catch a UAV during a concert performance. I have little doubt that some UAV operator is reading this blog thinking “That guy is stupid” while justifying why he/she catches their UAV.


I don’t catch my drone because I lack the skill to do so; like most people proficient with a UAV, I can put it precisely where I want it to land.

I don’t catch my drone because I’m averse to injury of myself and others. Safety always precludes “looking cool” or even saving a small cost of operation.

It may look cool to catch a drone and it may even reduce the risk of ingesting dust or dirt particles into a motor, thereby shortening the motor’s life. Perhaps think of it this way; A new motor may cost as much as $50.00. That’s a mere fraction of the cost of a trip to the emergency room and likely significantly less costly than an insurance deductible.

Happy flying!


Douglas Spotted Eagle is an sUAV operator with more than 500 hours of lDSE-droneIconShotogged flight time on various airframe types. He is also a USPA Safety and Training Advisor (at large), and a USPA AFF instructor. Safety is his priority in all aerial endeavors.






Image result for drone crash, buildingAs sUAV/drones become more and more popular, it seems that more and more of them are striking the sides of buildings, trees, or poles without the pilot understanding why.
“It was flying fine and all of a sudden it zipped up and into the side of the building.” “Everything was great until the drone had a mind of its own and flew straight to the ground.”
“The drone was flying over the trees and all of a sudden it spun around and dropped into the trees.”

Reading forum conversations around the internet suggests this is a common, yet unfortunate and avoidable experience.

First, let’s establish that flying in GPS mode may be ineffective when very close to a building. Signal may be lost, and this could explain a few of the building strikes.

However, far and away more likely in most instances the UAV was caught in a “rotor.” These are also known as up/down drafts, lee waves, or cross-winds, depending on which aviation discipline one adheres to. Needless to say, these phenomenon do exist, and play havoc with any sort of aerial activity whether it’s wingsuiting, parasailing, skydiving, model aircraft flight, swooping, small aircraft, and particularly light-weight multirotors.

Image result for wind turbulence map
These “waves” are indicators for manned aviation and construction crews, yet the principle is
only a matter of scale.

Even when a manufacturer provides a statement of stability in “X” winds, this should not fool a pilot into thinking that the sUAS is turbulence-resistant. Given enough turbulence or infrequency of a wave, the UAV will become unstable.

It’s always better to be down here wishing we were up there, instead of being up there wishing we were down here.

The first rule is to set wind limits. Small quad-craft should stay on the ground at windspeeds of greater than 12mph/5.5 meters per second. Hexcopters should consider grounding themselves at 22mph/10meters per second. Of course, this figure may vary depending on your organizations policy and procedures manual, insurance requirements, or payload on the sUAS.

This video provides some demonstration of the cycle of the wave and how a gyro and accelerometer might cope with the cycles. Notice how all the aircraft are “cycling” in an attempt to maintain altitude and position, even as the waves of the wind rotate?

Truly, knowing about them is half the battle. Staying away from them is the rest of it. Failing the former, being able to manage the craft in turbulence is the next-best step.

A building blocks the wind on one side (windward side) and on the opposite side (leeward side) the wind will pay all sorts of havoc with any flying object. Winds will extend in distance up to four times the height of the obstacle, and two times the actual height.

Understanding Turbulence 2

40×4=160 feet. Therefore, for 160’ beyond the obstacle at ground level, your multirotor is at risk for catching either a down draft or an updraft.


OK, say there is a building that is 40 feet in height, and you have a medium wind blowing. Gusting or steady, it makes no difference.

40×4=160 feet. Therefore, for 160’ beyond the obstacle at ground level, your multirotor is at risk for catching either a down draft or an updraft. Either way, the airframe/hull is not in clean air. In extremely high velocities (high winds) the ratio of obstacle/distance may be as great as 15X (of course, a UAS would likely not fly in these winds)!

In terms of height, depending on wind velocity, the UAV may have to climb as high as 80’ to find clean air above an obstacle. yet at 80′ AGL, the winds are likely entirely different as well, depending on the weather and other obstacles in the area.

The air goes over the obstacle and is “pulled” to the ground (downdraft), where it then “bounces” upward (updraft) and tries to resume its level flow.

These phenomena are entirely independent of  sinks,thermal rises, dust devils, and the like.

This also occurs in natural/unbuilt up areas. Trees, canyons, ridges, rock-lines; any large object will incur rotors. Avoid them. It’s virtually impossible to determine exactly where the down draft vs. the updraft may be occurring, and the location of these dirty winds will change with swind velocity.



When wind flows between buildings, the mass of the air/gas is compressed. This results in an increase in velocity. Think of squeezing hard on a tube of toothpaste, compressing the contents through the tiny hole in the end of the tube. This increases the speed/velocity at which the toothpaste squeezes out. The same thing occurs with moving air between buildings or other solid objects.

Depending on the wind speed, the increase may require as much as 4-10 times the distance before the winds return to “normal” velocity seen before the gap or corner.

Image result for Wind
Image courtesy of Rheologic

Ground winds and winds “aloft” (true winds aloft are beyond the reach of most UAS operations) are rarely equal. Winds at 50′ are rarely the same as winds at ground level in an urban or suburban environment.  Even small berms in the ground can cause jarring turbulence (as shown above) that settle in the low areas. These urban “microclimates” can be very problematic for light weight UAS in required-precision environments.


Here is a more complex example of winds blowing at 22mph in an urban environment.

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Compression of the flow due to building dynamics push the wind into more than 40mph in some areas. While the overall winds, and reported winds in the area suggest that the windspeed is perfectly acceptable for most commercial aircraft, turbulence and accelerated velocities within tight areas are far beyond the risk limits of most small UAS’.

Flying from warm sands to flying over water on a hot summer day may also create challenges to smooth and level flight.

DUST DEVILSImage result for dust devil

Dust devils are summertime phenomena that can be very dangerous to humans anywhere a UAS may be flying. If they happen in a city, there is usually ample evidence of their existence, as debris flies high in the “funnel.” These nasty actors can show up anywhere there is hot asphalt, sand, dirt, and if that mass of rapidly moving air connects with a cool surface, they can turn violent very quickly, slinging a sUAS far from its intended flight path.
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Dust devils in the Nevada desert can be frightening, especially when two or three combine into one vortex.

If by chance a dust devil is seen climbing in the distance, prepare to bring the aircraft home and land. If the dust devil is anywhere near the vehicle, climb in altitude while moving in any direction away from the dust devil. They are usually very short-lived.

Image result for dust devilImage courtesy Washington Post

How do we avoid getting caught in turbulent air? The long answer is “experience.” Flying in these challenging spaces teaches us to find the lee, based on the behavior of the UAS, which will always be slightly latent to the wind.
The short answer is to study environments. Look at the wind indicators that might normally be missed.  Learn to read the environment; it’s not hard once one begins to look for the details around buildings, trees, brush, monuments, chimneys, and other ground obstacles.

Two standard practices that may save pilots from troubles;

  • Always use a windmeter/anemometer, and check the winds frequently in midday flights.
  • Have a corporate or personal policy of a hard-deck/stop speed.  This eliminates wishy-washy/should I/shouldn’t I decisions in the field.  Our cap for teaching students with a Hexcopter/Yuneec Typhoon H is 16mph. If a gust crosses 16, we immediately stop, and wait it out to determine the wind trendline.

Another practice (although not standard) is to put a 5′ stream of crepe’ paper on a stick at eye level or so. This WDI, or Wind Direction Indicator, will immediately demonstrate changes in windspeed or direction, both clues that the weather may be rapidly shifting.

Determine distances from obstacles as accurately as possible prior to flight in order to best understand where the rotors will occur.  Doing so goes a long way to maintaining control and safety when the drone is in flight. With a bit of experience, one rarely needs to worry about obstacle turbulence.

Happy flights!