Flying drones in large cities can be a rewarding proposition for drone pilots. Drones can be used to capture the magnificent skyline during golden hours. Apart from this, benefits of using drones for construction monitoring and building inspections have also been well-documented by now.
However, flying drones in large cities is fraught with risk. Arguably, the biggest risk is the heavy magnetic interference caused by steel and electronic objects. These are some potential causes of interference that can hinder your drone flight, endanger drone safety and even cause a crash:-
- RCC Structures
- Concrete Slabs
- Metal Roofs
- Steel Structures
- All Wi-Fi Devices (cell phone, Apple Watch, Bluetooth speakers, routers)
Perhaps, it was this inexperience of flying in areas of magnetic interference that got 29-year old, Paolo Prosetti in trouble. Paolo, a Swiss tourist crashed his drone into the 21st floor-window of a Manhattan building in October, 2018. You can check out the coverage of this incident which shows Paolo being handcuffed after this misadventure.
So, how can you ensure that you do not get into trouble like Paolo? Fortunately, we have compiled a list of some common-sense but effective measures that will help you do just that. Let’s start with some important pre-flight measures –
PRE-FLIGHT Instructions for Safe Flight
- Detect Points of Interference
Drone pilots can detect interference before setting flight. The first and easiest way to do so is via the DJI Go4 App. Using a spectrometer is another option. A spectrometer can detect interference (including 5G interference) across a wider range of frequencies.
Typically, most Wi-Fi devices operate at 2.4 GHz frequency. So, this frequency band is likely to be the most saturated.
- Use a Faraday Cage or Faraday Shield
Exposure to powerful magnetic interference can “fry up” a drone’s flight controller, and cause your drone to fall from the sky.
A simple way of preventing this is by using a Faraday cage. A Faraday cage is nothing but an enclosure that reduces magnetic interference. For instance, wrapping the flight controller with a piece of carbon fiber can act as a rudimentary but effective Faraday shield.
- Calibrate your Compass Properly
Because steel objects in vicinity can result in improper compass calibration, we strongly recommend that you conduct your calibration in a secluded and interference-free environment.
- Set an Adequate RTH Altitude
RTH or Return to Home is a useful but commonly misunderstood DJI feature. When RTH is activated, the drone will fly back to the home point. To ensure that your drone does not crash with any structure during this return flight, you MUST set a RTH altitude which is higher than the tallest point in vicinity.
- Activate Obstacle Avoidance
This is another pre-flight precaution that you can exercise. However, remember that this feature may fail to work for shiny surfaces like glass windows.
Apart from pre-flight measures, the correct flying technique can also help drone pilots reduce the possibility of a drone crash.
FLYING TECHNIQUE for Ensuring Drone Safety in Interference-Heavy Environments
- Fly Farther Away
This is a no-brainer. The easiest way to reduce magnetic interference is to maintain a safe distance (around 100 feet) from all sources of potential interference. You might have to purchase a camera with high zoom to capture the required imagery from afar.
- Fly in Atti Mode
A DJI drone comes in 3 flight modes – GPS, Attitude, and Sport. By flying in Atti Mode, drone pilots can eliminate the possibility of a drone crash resulting from signal loss.
- Prop Guards
Using Prop Guards is another way of protecting your drone in event of a crash. However, your drone will be more difficult to fly when you use prop guards.
Some Final Thoughts
Flying drones in large cities is strictly the domain of drone pilots with advanced flying skills who realize the importance of following a pre-flight checklist for enhanced drone safety. Apart from magnetic interference, drone pilots must also be cognizant of the latest drone laws when flying in such high-risk areas. Finally, do not forget to purchase drone insurance that provides adequate coverage before setting flight.
If you found this information useful, you might want to check out other blog posts as well. Watch this space for the latest and most exciting drone news and updates!