New drone pilots will have a crash sooner or later and the odds are that it'll be a crash that causes damage to the craft. It'll almost certainly be caused by a very common error.
Here at Heliguy our tech team see the same mistakes cropping up time and time again and, so it seems, do DJI, the world's biggest drone manufacturer. On the DJI forum they've listed the top 10 common pilot errors. DJI are able to analyse onboard flight data so, even if you're convinced that there was something wrong with your drone, they could point the finger at you.
1 Mid air combination stick commandThe CSC is the method pilots use to arm their motors before take-off. It involves pulling both sticks to a bottom corner (inner or outer). It can also be used to stop the motors after the drone has landed, although it's not recommended as it can sometimes cause the drone to flip over on the ground. The CSC movement is too extreme to happen in normal flight but, if you make it happen, the motors will cut out and your drone will plummet. The only situation in which you would do that would be an extreme emergency when safety becomes more important than the survival of your aircraft. [caption id="attachment_4413" align="aligncenter" width="555"] The Combination Stick Command (CSC)[/caption]
2 Losing a propellerEven self-tightening props need to be firmly tightened before take-off. You can't recover when you lose one of four props so a crash is inevitable. Always check your props for damage and tightness before each flight. [caption id="attachment_4414" align="aligncenter" width="555"] Check your props are tight[/caption]
3 Return To Home (RTH) collisionAn automatic return to home usually happens when the drone loses the signal from your transmitter. That's one of the reasons why it's important to keep your UAV in your sight all of the time. If it disappears behind something like a tree or a building not only does it vanish from view but it will also lose transmissions from your controller. An automatic return to home will make the drone ascend to a pre-set height before flying straight home, regardless of what is in the way. So that building you lost the signal behind could take a direct hit. It's important to adjust the RTH height in your software so that your drone can clear any obstacles. More importantly don't get the craft into a position where RTH will be triggered.
4 Autolanding a long way from homeIf you get a first low battery warning more than 20 metres away you will need to cancel the automatic return to home within 10 seconds, if you want to continue flying. At the next stage of low battery warning your drone will auto land. You will only have control of pitch, roll and yaw. That's why it's best not to ignore low battery warnings. An auto land near the home point is infinitely preferable to an auto land into a distant tree or lake but it's best to bring it home earlier. [caption id="attachment_3526" align="aligncenter" width="555"] The DJI Inspire 1[/caption]
5 Flying out of sightDon't do this. It's dangerous and against the rules in most countries. Just because you have a camera on your drone doesn't mean that you can see its surroundings. Judging distances and seeing things like power lines are extremely difficult too. Always keep your craft in line of sight. Also if you can see it there's less chance of your radio signal being lost.
6 Flying backwards on FPVShooting video while flying your drone backwards produces some great shots. For one thing your props won't get into the frame. However there's the danger that your eyes could become glued to your video monitor. That means you don't see what the drone is heading towards. Lots of crashes happen this way. Keep switching your gaze between monitor and craft. You wouldn't dream of reversing a car while staring out of the front window.
7 Flying indoorsCrashes indoors are very common. The GPS signal indoors is either poor or non existent. You need to practice in Atti mode outdoors to get the confidence to be able to control your drone inside. The DJI Phantom 3 and the Inspire 1 have vision positioning and ultrasonic height sensing but even these can be fooled. If the floor is too plain the vision positioning, which locks onto marks or patterns, won't work. Similarly if the floor is too soft the sound waves won't reflect well enough. Your drone will also rise above obstacles on the ground so, if it hovers across a floor and over a table, it could hit the ceiling as it compensates its altitude. [caption id="attachment_1539" align="aligncenter" width="555"] Vision positioning on the DJI Phantom 3[/caption]
8 Not cancelling Return To Home
If your drone is more than 20 metres away and gets to the first low battery level it will automatically return to home if RTH isn't cancelled. Some pilots land the aircraft themselves when they get the warning without cancelling the RTH. No sooner have they touched down than the drone has taken off again, and climbed to the RTH height. That can cause a lot of panic. Some pilots have been known to try No 1 the combination stick command with expensive results. In this situation you have the choice of letting the drone return to home automatically or taking control by cancelling RTH and landing it gently, back at the home point.