How to Safely Fly a Drone in a City

Flying a drone in an urban environment requires special skills and concentration from its operator.

A city is filled with many obstacles, such as tall buildings and trees, signal interference, and flying over people is extremely dangerous.

News of drone collisions with various buildings, including residential buildings, is received periodically, so every "pilot" who wants to fly a drone in a city must improve his/her skills in a safe environment beforehand.

In this article, you will find some useful tips for managing a drone around your city.

How to Safely Fly a Drone in a City

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With proper use, drones can record videos from angles inaccessible to conventional cameras, and for urban environments, drones are virtually the only option for safe aerial photography from medium altitude.

Moreover, drones allow you to collect various critical information (from inspection of tall structures to assist in emergency situations) without any risk for the pilot.

Launching a drone in crowded places carries two key potential risks: signal loss caused by magnetic interference and drifting caused by air flows between various buildings.

Before flying, make sure that your chosen area does not fall under any official flight bans.

The most reliable way to prevent loss of control and ensure accurate positioning during flight is to calibrate the drone compass.

To do this, you need to find an open field about 10 miles away from places with oversaturated magnetic fields and radio signals.

Avoid parking structures with metal fences and cellular towers, remove your watch and metal jewelry, as even the slightest magnetic disturbance interferes with the procedure.

Follow the instructions on how to calibrate your drone model compass.

With minimal interference, magnetic declination will be taken into account, allowing you to operate with a higher degree of accuracy.

Most consumer drones are equipped with intelligent flight modes and stabilization systems to ensure a smooth and stable flight.

DJI drones have 3 main flight modes - P-Mode (Position mode), A-Mode (Attitude mode for low GPS signal or no signal, and low light for sensor operation), and S-Mode (Sport mode for maximum speed flight).

All three modes are available via the remote control. The Position and Sport modes rely on GPS and GLONASS to maintain the drone's position. 

Most flights can be performed in Position mode, as a drone can hang in place and easily return home, but in some cases, the signal interference may be too strong.

In Attitude mode, or ATTI, the drone retains altitude, though, may drift away from the wind, but this is the only mode that is suitable for operation in environments where the signal is not working, lost and/or severely distorted.

Note that although the ATTI mode will disable the GPS for navigation, the GPS module still finds the drone in the background, which means it cannot be used to bypass restricted flight areas.

How to Safely Fly a Drone in a City

You can switch from Position mode to ATTI mode by using a lever on the controller. The DJI Go app also provides access to a shortcut if multiple flight modes are enabled.

If your drone can no longer operate in Position or Sport mode, it will automatically switch to ATTI mode.

It is always preferable to switch to ATTI mode manually beforehand, rather than being caught off guard when the drone activates the mode itself.

As a basic rule, do not fly between tall buildings with GPS on. Many signals between buildings can cause interference and create a significant compass error by knocking the drone off course.

The worst strategy for flying in a busy zone will be relying on the Position mode which stabilizes the drone and makes its operation as simple as possible, though it may suddenly change to ATTI if the signal is lost.

In this case, flying a drone, drifting in the wind, is a challenging task that requires many hours of preparation.

Training in large open areas with a small number of trees and obstacles is the best way to learn how to maintain control over your drone when it refuses to automatically hang in place.

The first time you turn on the ATTI mode, your drone starts drifting immediately, which can scare even the most experienced pilots. You need to be ready for this, having studied how to fly a drone in advance to guide it along a given direction.

During a flight next to taller structures, your drone may lose its connection or discharge to a critically low level before the time. In this case, the Return to Home function should be automatically activated and provided the compass is correctly calibrated, the drone will return to you on its own.

Creating a safe flight direction requires the pilot to be able to determine the height of the tallest building in the surrounding terrain, after which he/she should add approximately 10 ft (3 m) to ensure that the drone bypasses any obstacles.

The Minimum Obstacle Clearance Altitude (MOCA) can be defined in several ways. For example, you can try to find information about the height of buildings online.

Another way is ascending vertically against the tallest obstacle with a Steadicam set at a fixed height before the obstacle crosses the horizon.

The inclusion of obstacle avoidance sensors is another recommended precaution. However, the sensors do not always identify reflections or shiny surfaces.

Therefore, setting MOCA and the correct Return to Home Altitude is extremely important.

How to Safely Fly a Drone in a City
How can I fly in ATTI mode?

Another essential safety measure is propeller protection. It is an effective tool to prevent a serious accident if your drone hits a wall or a propeller of your outdoor ceiling fan, etc.(like one of these)

The protection increases the weight of a drone, which will slightly increase the consumption of the battery, so additional practice is required before the flight.

Depending on the drone model, when using propeller protection, the obstacle avoidance systems can be disabled.

Complex work that requires navigation in a busy area must be accompanied by constant visual contact with the drone and may even require an extra observer.

It is generally acceptable to fly a maximum distance of 0.3 miles (500 m) from your location, but in a crowded area it is advisable to keep your drone in close proximity: 490-820 ft (150-250 m) when flying at altitudes not exceeding 328-393 ft (100-120 m).

Launch your drone in Position mode until it reaches an obstacle, then switch to ATTI mode and continue ascending. At return, when the drone is close enough, you need to switch back to Position mode to make landing easier.

Drones save time, money, and effort when used properly, and can be particularly useful when inspecting tall buildings and structures. Knowing how to operate safely in challenging environments is critical if you plan to fly in crowded areas such as downtown. 

This requires training and practice to keep you from unintentionally getting into the news headlines.

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