In light of the exciting news that our customer, the Elk Grove Police Department, has become the first public safety agency in the country to receive an FAA waiver for BVLOS (Beyond Visual Line of Sight) drone operations across their entire jurisdiction at 400 feet without a visual observer, I wanted to take a moment to share some insights and clear up any misinformation.

Since launching the nation’s second DFR program in Redondo Beach, California, back in March 2020, I’ve learned a lot along the way. One of the first and most important lessons was figuring out the optimal altitude for drone operations to be most effective tactically. Over the past five years, every agency I’ve worked with that’s authorized to fly drones at 400 feet has consistently done so—and for very good, obvious reasons.

Let me break this down with a few simple examples. I’ll also explain why, in some (very few) cases, a 200-foot DFR system might be the right choice.

Let's start with why 400 feet is indisputably better than flying at 200 feet.

Reason #1: Your field of view is four times larger.

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‍“The higher we fly, the better vantage we have. We can be virtually on-scene faster with less obstructions.” - Lt. Nate Lange, Elk Grove Police Department 

This is a straightforward physics principle: the higher you fly, the more you can see on your screen. The clip above makes this easy to visualize, clearly showing that you can cover four times the area when the drone is at 400 feet compared to 200 feet.

The entire point of DFR is to see things. What’s the use of flying a drone if the suspect vehicle you’re searching for is just off-screen? How many things are you missing when you’re flying so low that you can’t even see them? 

Flying at 400 feet means you are four times as likely to find that fleeing suspect or missing child.

This example highlights how much faster you can search an area for an ALPR hit. At 400 feet, you can easily monitor a main road and track your suspect vehicle in transit. At 200 feet, a building might block your view, preventing you from seeing past it. When you’re flying low, this is a constant problem.

Reason #2: Your community will complain less about the noise.

“We used to fly at around 200 feet and we got too many complaints. We switched to 400 feet and the amount of complaints plummeted.” -Chief Keith Kauffman (ret.), Redondo Beach Police Department

I learned this lesson the hard way when I first launched our program. Initially, we would launch our DFR drone to about 200 feet and fly it straight to a call-for-service while climbing to 400 feet. Nearly every day, we received complaints from residents about a “drone zipping through the air above my house.” One day, I stood on the sidewalk and had one of our pilots fly over my head at 200 feet and thought, “Boy, they were right.”

We decided to launch at 400 feet and fly to calls from that altitude. Overnight, our community complaints dropped to nearly zero.

Why? Because drones are louder when they’re lower. This is a physics problem—don’t let anyone convince you otherwise.

This phenomenon is explained by the “inverse square law of acoustics.” This law states that when you double your distance from a noise source, the sound intensity decreases by a factor of four. This means the sound from a drone is four times as intense at 200 feet as it is at 400 feet.

If your drone can be heard, many community members will likely complain about it, especially if they’re in common flight paths. 

When deploying a new DFR program, the success of your initiative depends heavily on how much the community accepts and appreciates it. Reducing the likelihood of complaints is key to keeping that program operational.

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Reason #3: Your drone is tactically more effective when it cannot be seen or heard.
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“We don’t always want to be seen. If we did, we can always lower our drone to 200 feet. It’s better to have the option for stealth than be seen all the time.” - Lt. Nate Lange, Elk Grove Police Department

To be clear, the drone can still be seen and heard at 400 feet, but now you have to really be looking for it. The image above illustrates just how difficult it is to spot the drone at 400 feet.

Those of us with law enforcement experience understand that sometimes you don’t want suspects to know you’re there. We park a few houses away from a call-for-service for a reason. We stand off to the side of a hallway for a reason. Concealment is a tactical advantage. We don’t always want to reveal our location or presence immediately.

That doesn’t mean we have to stay at 400 feet forever, though. You can always approach a call-for-service at 400 feet and descend in altitude if the goal is to be seen and heard.

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The reasons above are why I was never willing to compromise when developing our detect-and-avoid system to support 400-foot beyond-visual-line-of-sight waivers.

That said, you can easily operate Flock Aerodome at 200 feet as well. Our goal has always been to provide you with both options without limiting you to 200 feet.

Here are the only reasons to fly at 200 feet:

Reason #1: The Drone’s Radio is Weak and You’re Stuck With LTE
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Don’t get me wrong—I believe LTE/5G is a great technology for some applications. The issue is, it won’t perform as well as radio when your radio line-of-sight is strong.

In fact, we offer a full DFR package operating on LTE/5G for those who need it, but we only recommend it to people who truly require it.

Why? Because LTE is often choppy and unreliable, it increases latency and limits you from flying high.

When cellular towers are installed, they are usually designed to point toward the ground (where most cellular users are). This is how they are typically optimized (there are exceptions). They never factored 400-foot drones into the equation when they were built.

You’re also sharing your LTE coverage with thousands of other people at any given moment. When a “big event” happens, you can’t risk the drone becoming inoperable because too many people are hogging the network. Even with dedicated public safety networks, this remains an issue. Remember, there’s a reason your agency has a dedicated radio band that is largely unaffected by these types of problems.

If you’re demoing an LTE drone, ask the people demoing it to fly it at 400 feet in a handful of your most critical areas. Do this during times of peak LTE usage. Fly miles away on typical routes. Also, remember not every LTE provider’s coverage is the same. One area may be great for one LTE chip but not so great for another.

If that same LTE drone company suggests they can “fly on radio too,” ask them to fly their drone via radio in an urban environment three miles away and see if the connection quality remains strong enough for your operations.

Reason #2: The Drone’s Camera Isn’t Good Enough to Fly High and Still Read License Plates Half a Mile Away
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Flock Safety is a camera company, and this is something we understand deeply. As we build drones, we view them as flying cameras, not just flying computers. The whole point of the drone is to see something far away clearly. 

Some companies try to repurpose drones that were built to stay close to walls and low to the ground for inspections, then market them as “DFR drones.” It doesn’t really matter how close a DFR drone can get to a bridge. If you can’t read a license plate at the altitude and distance you need, what’s the point?

When you conduct a DFR demo with any company, ask them to fly the drone at 400 feet and zoom in on a license plate at least a quarter mile away. If they can’t do it, you’ll understand why they’re trying to convince you to fly low.

Reason #3: The FAA will not allow you to fly in your airspace above 200 feet.
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“200 feet is too low. I would only consider it if 400 feet wasn’t an option.” - Lt. Nate Lange, Elk Grove Police Department

This is the only good reason to fly at 200 feet: you have to be compliant.

The good news? This applies to less than 0.1% of U.S. airspace.

Even better news: the FAA is often willing to work with you. Our FAA services team (free for customers) has obtained waivers for our clients to increase their maximum allowed altitudes.

It’s better to try to raise your maximum altitude with the FAA before settling for a less effective one.

And if you can’t? That’s okay too! We offer a 200-foot DFR system, and it’s still cheaper than everyone else. In fact, let’s talk about cost.

Reason #4: You (think you) cannot afford to fly at the altitude you want.
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To fly at 400 feet, you need to demonstrate to the FAA that you can consistently detect aircraft that aren’t broadcasting an ADS-B signal. We’ve known this for years, which is why we were the first company to invest in radar for this purpose.

This investment has paid off. Our radar is nearly half the cost of our largest competitors and has been approved by the FAA for BVLOS DFR operations without the need for visual observers or cameras.

Not to mention, flying with radar doubles your sensor redundancy, making it twice as likely that you will detect an approaching aircraft and avoid a collision. Ask yourself: Do helicopters, private pilots, and military aircraft broadcast ADS-B 100% of the time? Do you want to make that bet?

We have always focused on providing our customers with the best system at the most affordable price. We invest in making our solutions more effective and more affordable. We never try to convince customers to choose something that isn’t actually the best for them.

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I hope this helps cut through all the marketing gimmicks and misinformation out there. My recommendation is to always evaluate every DFR platform provider based on the above reasons and pick the best platform for your agency. Hold us all accountable and make us prove it to you.

Fly high, fly quiet, and fly safe.

Rahul Sidhu, Founder of Aerodome & VP of Aviation, Flock Safety

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