The word “drone” is an everyday term for unmanned aircraft vehicle (UAV) or unmanned aerial system (UAS) – an aircraft that is controlled either automatically, independently or by a remote pilot.
Drones come in all sizes and can weigh anywhere from a few hundred grams to several thousand kilos. They can be flown for different purposes – privately, commercially or for police work and other public operations. They can look different – some, like the common multirotor or multicopter, are similar to helicopters, while the fixed wing drone looks more like an airplane.
The two types differ in design and construction, and they are also used for different purposes. The multirotor drone is often used for photography and film work, while the fixed-wing drone is used to measure, map or monitor larger areas.
Learning how to manage a drone’s system means learning to understand and maintain an entire apparatus with internal and external systems and services including various functions, settings and risks. Some of this may only be perceived as technicalities, while other parts are crucial. But regardless, you need to know all the parts and how to handle them to fly as safely and correctly as possible.
Drones with propellers
Drones can have several propellers, which, combined with the varying speeds of the engines, create lifting power and movement. Normally, the drone has four arms and four propellers: two propellers spin clockwise (CW) and two propellers spin counterclockwise (CCW). In this way, the total rotational force becomes neutral. If a drone has more than one propeller, it is classified as a multirotor drone.
It is important that the propellers are installed in the right place. Incorrect mounting will cause an immediate crash. In most drone systems, the propellers cannot be mounted in the wrong way, but it is still important to check that they are properly secured. The propellers are subjected to high loads, and may crack easily. Check the blades for cracks before start by bending them gently.
Fixed wing drones
Some drones have fixed wings. This type of drone often has one or two propellers. It has other functions and is used for other purposes than the more common multirotor drone.
The main difference between a fixed wing and a multirotor drone is that the fixed wing type looks more like an airplane than a helicopter. These drones have longer range and flight time, and are also faster than a multirotor. Fixed wing drones often have to be tossed to start, and therefore require a runway.
The wings of a fixed wing mean the drone can handle a crash or engine loss better: the wings keep it sailing in the air, unlike a multirotor, which, if worst comes to worst, just falls straight down. However, the fixed wing cannot hover, nor can it evade obstacles as easily as the multirotor.
The camera on a fixed wing is often completely fixed or mounted in a two-axis gimbal, facing down, which can be good if you are mapping large areas. But if your purpose with the flight is to film or photograph, a multirotor with a movable gimbal is a better choice. You can read more about this further down in this document.
There are also hybrid drones with fixed wings and more than two propellers.
The radio transmitter – the drone's steering wheel
The radio transmitter communicates with the drone, and controls its movement and camera functions and more. If the contact with the radio transmitter is broken, many drones fly home automatically and land. It is often a default setting that can be changed.
The location of the antennas is especially important during long distance flights. It is the long side of the antenna that should point towards the drone, not the tip (the tips lack the ability to transmit and receive).
The radio transmitter communicates with the drone via radio waves on several frequencies
The drone and the radio transmitter are normally connected through radio links of 2,4 GHz and 5,8 GHz. The higher the frequency, the more data can be sent with short delay, but with shorter range as a result. A frequency of 2,4 GHz is sufficient to transmit control and HD video (1080i) at distances up to 4 km within a legal power limit of 100 mW. The use of higher transmission power or a more powerful directional antenna to achieve a longer range is not permitted.
The GHz band is sensitive to physical obstacles, making it important to ensure unobstructed view between the radio transmitter and the drone. It becomes even more important and sensitive at longer distances.
In some cases the radio transmitter can communicate with the drone through 4G or a computer instead of the GHz-frequencies.
More information on the permitted frequencies and power levels for drone operation [linkki: https://traficom.fi/en/communications/radio-licences-and-frequencies/frequency-planning-and-use/frequency-issues-unmanned-0 (External link)]
Identify the drone from ground
Direct remote identification can be used by the police and other authorities to identify the drone in the air and obtain information about its marking, registration, operator etc.
The drone follows you
Follow-me mode is a function available only for rotorcraft drones. Just as it sounds, the mode makes your drone automatically follow you or your radio transmitter. If you have the follow-me mode activated, your aircraft must be no more than 50 metres away from you in order for you to quickly take over the control.
Keeping track of boundaries in the airspace
After 1 January 2021, all types of open category drone systems, except C0 and C4, must be equipped with geo awareness. This function means that, as the remote pilot, you should be able to get information about boundaries in the airspace in relation to your drone's position and altitude etc. In addition, you should be warned of any boundary violations in the airspace.
NOTAM – information about what is going on in the airspace
NOTAM stands for “notice to airmen”. It is a service that continuously publishes important information about what is going on in the airspace. NOTAM is for all types of pilots. It is a must even for open category remote pilots to be fully aware of any warnings or flight bans while planning the route.
NOTAM information is available on the Fintraffic ANS Oy Aeronautical Information Services website at https://www.ais.fi/en (External link). (External link)
The Aviamaps service offers NOTAM information as a map service on www.aviamaps.com (External link). If your planned flight route contains restrictions, they will be displayed in the map service. Please take these restrictions into account and change your flight plan or time.
AIP
AIP (Aeronautical Information Publication) is a collection of data that you should read before take-off. Most countries publish a national AIP with information about the conditions of flying to, from or above the airspace and airports of different countries.
In Finland, Fintraffic ANS Oy Aeronautical Information Services publishes the Aeronautical Information Publication, which is available at https://www.ais.fi/ais/aip/en/index.htm (External link). (External link)
RTH – drone flies to home position automatically
The RTH (return to home) function is frequently used when flying drones. RTH makes the drone automatically fly back to the start position or to your radio transmitter, depending on which setting you have chosen.
If the communication between the drone and the radio transmitter is interrupted for a number of seconds, RTH can be activated as a safeguard. The drone will then fly to the start position at the preset altitude and land automatically.
It is important to understand that the altitude at which the drone flies home is always in relation to its starting position. This means that the drone doesn’t understand the actual height from the ground – collisions with masts, high mountains etc. can occur on the way back to the start position. However, some drones have anti-collision sensors that can see and avoid obstacles.
The RTH function can also be activated manually, if, for instance, you lose the orientation of the drone or if the video link breaks. Don’t use RTH if there is a problem with the compass.
Drone’s built-in compass calibration
Calibrating the compass is important for the drone system to sense the Earth's local magnetic field. If, at a new location, a calibration is performed incorrectly or not at all, this may result in a crash and the drone exhibiting irregular and unpredictable movements. Find out how you perform compass calibration under “Checklists” in section 5: Operational procedures.
Keeps camera stabilized
The purpose of a gimbal is to counteract the drone's movements and vibrations during the flight, in order to keep built-in or external camera stabilized. The result is a horizontally straight image without shaking. Fixed wing drones don’t always have gimbals, but may instead have a fixed camera facing down, depending on the purpose of the flight.
Maintenance of drone’s batteries
All C rated drones, except C4, have to be powered by electricity and therefore require batteries to be able to fly. In the case of privately built drones, there may be other requirements. Batteries are sensitive and require special treatment. Cold temperatures can be harmful so the batteries are best kept at room temperature before every flight. A piece of advice is to keep the batteries in your jackets inner pockets. A cold battery has a less capacity and can cause a crash in the worst case scenario. Some drones have built-in protection that measures the temperature of the battery, alerting the remote pilot to low temperatures and suggesting what to do during cold operation. Don’t ignore these alerts – take them seriously! Some drone systems can also preheat the batteries before flying.
If you do not intend to take your drone immediately on another flight, charge the batteries according to the manufacturer’s instructions to an appropriate storage voltage after each flight. Remember to ensure proper voltage also during low season and store the batteries in a cool, fire-safe place, never in direct sunlight.
Many modern drone batteries have a special mode for storage voltage: if the next flight does not take place within ten days from charging, the battery will automatically be partially discharged. This is done to protect the batteries, since they may be damaged if fully charged for an extended period of time.
If the batteries are stored with a low charge (below 10 percent), they can take permanent damage and be dangerous to fly with. The batteries will lose their charging capacity, and even though they may seem fully charged, they may quickly stop supplying power to the drone without warning. Therefore, make sure to charge your batteries to the level recommended by the manufacturer as soon as possible after flight.
Li-Po (lithium polymer) and Li-ion (lithium-ion) batteries are the most common battery types in drone systems. Li-Po/Li-ion batteries require a special type of fire extinguisher. In addition to the properties of a regular dry powder extinguisher, the extinguisher must also cool down the object on fire. You can also put out a burning Li-Po/Li-ion battery with plenty of water. Find out what type of batteries your system has and what type of extinguisher is required.
The drone's motive power
All C rated drones belonging to the open category, except C4, must be powered by electricity. What is important then, is to make sure that the electricity generated inside the drone is not harmful to you or to anyone else. Therefore, specific requirements are imposed on the manufacturer, depending on the C rating of your drone. Check what applies to your drone. However, privately built drones do not have to be powered by electricity.
In addition, as the remote pilot, you should be alerted in time if the battery level starts to get low. This is essential to enable you to land as safely as possible.
Lighting is required
In order to improve the conspicuity of the unmanned aircraft flown at night, and in particular, to allow a person on the ground to easily distinguish the unmanned aircraft from a manned aircraft, a green flashing light should be activated on the unmanned aircraft.