It’s something that every drone pilot has thought that some time: what is the risk of flying a drone too high? Of course, there are the legal and regulatory maximum heights that pilots need to adhere to whilst they are flying their drone. But, what if they didn’t exist? What would happen if a drone was flown as high as possible. In this article, we are going to look at the legal issues as well as the environmental and high-altitude dangers that come from flying a drone too high.
The risk of flying a drone too high includes facing legal issues if caught flying above the maximum legal height, low controllability due to the reduced air pressure, loss of connection with the drone and high winds and water vapor could put the drone at risk.
The majority of the issues that come from flying a drone to high emanates from the fact that as you increase in altitude the quality and the properties of the air changes significantly from ground level.
As you increase in altitude the air becomes thinner. The fewer the number of air molecules that are available means that the propellers have to work harder in order to stay stable and displace enough air to maintain their altitude.
You can see a few of the highest drone flights at these YouTube links:
| Drone | Highest flight |
|---|---|
| Parrot AR drone | 473 m, 1000 feet |
| Self-made drone | 33,000 feet |
| First person view drone | 3000 m |
| DJI Mavic Pro Platinum | 8000 m |
| DJI Mavic Pro | 8200 feet, 2500 m |
Obviously, these drone flights do not adhere to many of the regulations which govern flying a drone. One of the most important drone rules is that you cannot fly your drone above a certain height.
In Australia, where I live, you cannot fly your drone more than 120 m above ground level. This means that it is less likely to come into contact with anything like a plane or helicopter and the rule is that as soon as you see a plane or a helicopter that you need to land as soon as possible.
If you are caught flying a drone more than the legal height you can face legal issues.
Which, is one of the more damaging risks with long-term impacts (such as a large fine and a potential criminal record) of flying a drone act high altitudes.
Legal issues
I do not know anyone who has been charged or arrested for flying the drone in a place that doesn’t allow drone flight. For most of the issues that I see online they come with a warning and an acknowledgement that you will not do it again. However, if you are a repeat offender all you go over government property or no-fly zones you can get into real trouble.
The thing about flying at high altitudes is that you can quickly go off course.
The high winds and the reduced ability to control your drone at the very high altitudes could potentially cause your drone to fly, inadvertently, into restricted areas.
To make sure that you understand exactly what heights you are able to fly at make sure that you are familiar with the local laws and restrictions in your country and local jurisdiction.
Here are a few links to some of the laws in countries that are particularly litigious around drone flight.
Drone flying restriction in USA
- https://uavcoach.com/drone-laws-in-united-states-of-america/#:~:text=You%20must%20be%20in%20a,Administration%20(TSA)%20security%20screening.
- https://www.faa.gov/uas/
- https://dronedj.com/2020/05/13/usa-drone-laws-faq/
Drone flying restriction in Canada
- https://tc.canada.ca/en/aviation/drone-safety/flying-your-drone-safely-legally
- https://www.cbc.ca/doczone/m_features/drone-laws-canada
Drone flying restriction in Australia
- https://uavcoach.com/drone-laws-in-australia/
- https://www.casa.gov.au/knowyourdrone/drone-rules
- https://www.casa.gov.au/drones/rules/sub2kg
- https://dronedj.com/2020/05/18/australia-drone-laws-faq/
Drone flying restriction in UK
- https://www.nottinghamshire.police.uk/advice/drone-law-uk
- https://uavcoach.com/drone-laws-in-united-kingdom/
Many countries have limited the maximum height that you are legally allowed to fly your drone as it is based on the minimum cruising altitude of manned aircraft which is at 500 feet. There is normally a 100 foot buffer between the lowest cruising altitude and the maximum altitude that you can fly in your country.
The cruising altitude will be set for the highest obstacle in the area so that manned aircraft with pilots know how to adjust their height as not to come into contact with any drones or other low-flying objects.
In most of the drone apps you can set an automatic maximum altitude that your drone cannot pass. Although, you can change that yourself and you can end up flying your drone very high. Based on the amount of range that common drones have it is unlikely that you will be able to fly high enough to lose signal from altitude.
However, you can get around these blockages with certain software changes.
This video shows that the DJI Mavic pro is able to fly at a height of 2500 m:
Altitude issues
The primary reason that your drone will become unstable at high altitudes is the quick drop in air pressure.
As you go higher into the atmosphere the air pressure reduces. The air pressure reduces because there are fewer and molecules down at sea level. This is the reason why mountaineers need supplemental oxygen when climbing high peaks. There are simply less oxygen molecules at higher altitudes.
As you fly your drone higher and higher you will likely see that you suffer from stability issues and if you go high enough your drone will stop being able to climb as it cannot move the propellers fast enough to displace enough air downwards to climb any higher.
Low control
Because each movement the drone makes depends on the propellers moving air, the fewer number of air molecules which are available to move the harder it is for the drone to fly stop this manifests as stability issues were also slow and sluggish response to joystick movements.
You can see in a number of YouTube videos that the maximum altitude that the drones reach often correlates with its lowest stability flight.
Water vapor effects
Humidity changes significantly as you fly higher. The relative humidity can become greater as you gain altitude because you enter areas in which clouds are forming. But, in general it becomes less as you ascend to higher altitudes. Most of the water vapor is at lower altitudes.
The relative humidity is about 78% near the surface of the earth and about 44% at 4.2 km up.
Temperature also plays a huge role in determining the relative humidity as the colder the air the less the air is able to hold onto moisture and therefore the humidity can be higher.
As you are flying your drone higher and higher through varying humidity you run the risk of having water condensate on the electronic components of the drone as well as on the inside lens and camera.
Temperature effects
The various metals and composite’s that are used in a drones construction respond differently to temperatures because of their specific heat capacity. If the temperature of the surroundings drops dramatically the metallic parts of the drone will also reduce in temperature quickly.
If this corresponds with a high humidity area a significant amount of moisture can collect on the drone surface and the surface of the electronic components.
If you have noticed that there is a significant amount of water that has formed on the drone there are a few things that you can do.
What to do if your drone collect condensation
Firstly, you need to make sure that you remove any electronic components such as the battery which powered the drone.
Allow the drone to dry for at least five days after rotating the drone in as many directions as possible to quickly remove all of the residual water. Gently shake the drone while it is being turned into different positions to dislodge any smaller droplets. If possible completely disassemble the drone to allow any remaining liquid to drain away and to begin clean the internal components.
Now here’s the biggest thing: do not put your drone in rice or silica!
Any residual water can be removed without having to put the drone in rice. There is a myth going around that rice will absorb all of the water. That is just simply not true. If you want to be sure to blow out all of the water before leaving it to dry you can use a hairdryer on the lowest heat setting to remove some of the moisture.
The best thing you can do is leave the drone in a dry location for as long as possible but no less than five days.
After five days you can carefully turn the power back on to see if your drone has survived.
Remote connection is lost
As you fly higher and higher the connection between your drone and its remote control will get weaker. The strength of the connection between the drone and the controller depends on the type of technology that is being used. When you are flying straight up there is generally a direct line of sight (unless you are flying through clouds) which means that we can ignore environmental factors such as buildings and other direct line of sight obstructions.
The maximum distance that a drone can fly away from its controller is approximately 10 km. This is with DJI’s proprietary communication system OcuSync 2.0.
This proprietary video transmission system outperforms Wi-Fi and other radiofrequency transmission systems. Its secret lies in the fact that it uses a much more effective digital compression allowing it to transmit the high definition video over long distances. Because of the technology it can also work well in places with strong electromagnetic interference.
OcuSync transmits over distances of about 7 km (4.3 miles).
Recently, DJI have released a second version of this technology. This allows the video transmission feeds to be delivered up to a maximum of 10 km (6.2 miles) this is in credibly impressive and can be found in drones such as the DJI Mavic Air 2.
As long as there is direct line of sight between the remote-control and the drone you should have no issues in losing signal.
Wi-Fi, which is used in popular drone such as the DJI Mavic air, has a maximum distance of between 300 and 2,000 m depending on the type of Wi-Fi signal used.
What happens if you go out of range?
There are a number of symptoms of a drone going out of range and this includes a graying of the live stream video which quickly cuts off.
Exactly what happens to your drone if you lose the connection depends on the type of controller and drone that you have. If you have a consumer level drone that has an automatic return to home feature then you can rest a little bit easier since the drone would likely simply return to its takeoff spot.
On the other hand if your drone does not have an automatic flying stabilization feature or a return to home function that it is likely your drone will simply crash land close to where ever you lost the signal. For more information about what happens if your drone goes out of range check out my other article – what happens if your drone goes out of range a full guide – click here to be taken to article.
High winds
Lastly, as you ascend to higher altitudes and you fly your drone above the legal limits you may notice a significant change in the wind speed and direction from that observed at ground level.
The wind may be strong enough to quickly and easily throw your drone off course and any updraught is particularly damaging to drones.
Thi s because its vertical maximum speed is severely limited compared to its horizontal maximum speed. In other words, your drone is able to withstand buffeting and wind gusts from the side but is not able to withstand significant wind gusts forcing it up and down.
Many drones come with advanced high wind warnings which I recommend that you pay particular attention to if you are flying at high altitudes or you notice that your drone is acting strangely as you ascend.
Summary
In this article, we have gone over what the risk of flying a drone to hire is and look to all of the potential risks that your drone is likely to encounter.
Besides the legal risks there are many environmental factors which come into play at higher altitudes such as changes in humidity and windspeed as well as the drop in air pressure which makes the motors work harder and causes the drone to lose stability and the ability to climb in a predictable manner.
Before taking off and flying at a high altitude you should pay particular attention to all of the weather changes your drone is likely to experience as it ascends. Buying a drone that has an automatic return to home feature will be the ultimate failsafe should anything go wrong during your high altitude flight.
