Crashes are almost a guarantee with drone flying. There are so many causes for drone crashes that it is almost impossible to plan for and anticipate every scenario. There are, however, several things you can do to reduce the probability of a crash:
Know your environment: Before you get airborne, be sure to scout the area. Look for towers, cables supporting vertical structures, trees, power lines, buildings, and other structures that may block your drone’s flightpath.
Use a spotter: If you are flying with a first person view device, consider using a spotter to watch your drone. A spotter is a second person that keeps an eye on your drone, sometimes with binoculars if you are flying at long distances. First person views are restricted to the view of the camera that is streaming your flight. A spotter can help keep you from danger as long as you remain in sight.
Use a level and stable take-off and landing location: Your drone will automatically calibrate before taking off. Make sure you have a stable, level location for taking off and landing so that your drone can calibrate accurately.
Fly in good weather: Good weather means no wind, mild temperatures, and no precipitation.
Battery life: If your drone’s battery is running low, you need to bring your drone home. If you don’t think you have enough juice to bring it back, slowly bring the drone back to earth and then go pick up your drone.
Even if you take all of the items above into consideration, there are several other factors that can contribute to the loss of control of your drone and a subsequent crash such as random mechanical or computer failure, battery failure, unanticipated collision with wildlife, or a run-in with a zealous anti-drone advocate.
Vortex ring state
The air that is forced down through your propellers is called downwash. Check out this picture showing a helicopter’s downwash on the surface of water. If your drone descends to quickly, it will descend into its downwash which will cause it to lose lift at an increasingly rapid pace. This condition is called a vortex ring state, and if it is not corrected quickly, your drone will come crashing down.
You can avoid VRS simply by controlling your rate of descent. Refer to your user manual to learn a safe rate of descent for your particular drone.
GPS lock
Most drones today are equipped with GPS capabilities. Before you start flying, you should ensure your drone has a GPS lock. The GPS lock tells your drone where your take-off and landing location is using GPS coordinates. This is critical in case you lose connection with your drone, regardless of whether you lose connection because the drone is flying out of range or some other communication failure occurs. With the GPS lock set, the drone should return to the GPS locked location.
This feature is fantastic in the event you do lose communication with your drone. Without a GPS lock, the drone flies until it runs out of juice or collides with something.
Be warned that some drones do not forget their GPS lock. This means that you must be sure to reset the GPS lock every time you fly your drone if you are flying in different locations. Otherwise if your drone goes out of range, it may try to return to a different location entirely because of the GPS lock.
The DJI Phantom had a known bug that would cause Phantoms to fly away upon arming. The device would think that it was out of range, and it would automatically take off in the direction of the previous GPS lock. DJI has provided a software update to fix this bug, it’s still a good idea to be aware of this in the event you’re ever flying a drone that behaves in this manner.
You should never rely on a GPS lock; it is only a backup to be used in the event of an emergency.
