As safety is so critical, modern consumer drones have plenty fail safe drone settings and features to make your flight as smooth and safe as possible. They are however not universal for each and single flight. Understanding them is therefore the key to making sure that you maximise your flight experience. Below, I will go through some very basic mode switches and settings found on most consumer* drones.
- RC/Wifi switch – allows to switch between RC and Wifi modes. In RC mode, the remote controller gives commands to the drone. In wifi mode drone may be controlled either by RC connected to the app or ONLY by app (depending on drone and set up). You need to decide how you want to control your drone before take off. This switch is usually on the drone. If for whatever reason you find it on controller, do NOT use during flight (you will lose connection).
- T/N/S, Cine/Normal/Sport or S/N switch – allows to change between Tripod mode (limited speed + obstacle avoidance), Normal mode (normal speed + obstacle avoidance) and Sports mode (fastest and no obstacle avoidance, not to be confused with manual mode). Normal mode is also called Position mode. In this mode you will also be able to access additional DJI creative modes, called Quickshots. Some drones have ATTI switch instead of Tripod switch. In ATTI mode GPS is not active. DJI FPV has additional modes (Acro and Manual) for acrobatic flying (not available on typical “consumer” drones). Those require good experience to handle the drone and can sometimes be activated by using 3rd party software (like with rooting your phone, you will lose warranty).
- Beginner mode – can typically be activated from the app level. It will limit the altitude to 30 m and the distance to 50 m (those limits may slightly differ depending on drone). You will probably only use this in the very beginning or when trouble shooting your drone. Once you gain confidence you will not need this mode.
- Max Altitude and Max distance – the factory max altitude on DJI drones is 500 m above. Since you are not allowed to fly up to this level, it is better to set it at legal limit, which usually is 120 m. There is no max. distance preset on the drones. You will be able to fly to the limit of your drone-controller connection. Bear in mind, that this is not legal either as you will have to keep your drone within Visual Line of Sight (VLOS). 500 m is generally considered the VLOS limit, so you may want to set the max distance to that.
- Low/ Critical battery warnings – typically, those are preset at 25% and 15%. At the “low” battery warning, your drone will initiate the Failsafe procedure. At “critical” level it will land where it is. Be very careful when adjusting those levels. Bringing them down may seem tempting (and sometimes I do override them), but if you are flying far, in windy conditions and/or unknown location you will want to bring your drone close before any warnings appear. Do not change the “critical” warning to less then 10%. The less battery life the drone has, the less accurate the readings. You may crash your drone if it turns out that you don’t have enough battery life to land. Landing with some battery remaining will also allow to locate the drone using the “Find my drone” feature (your drone will record GPS position, if GPS was available at time of landing. 10% battery life is also legal requirement when landing your drone.
- Obstacle avoidance – set of sensors that prevent drones from crashing into objects. Not all drone have this feature, so make sure your drone has it, before you purposefully fly into anything 🙂
Failsafe refers to set of procedures that drone kicks in when out of control or in emergency. RTH/ AUTOLAND/ HOVER – alternative drone behaviours that you can and SHOULD predefine depending on where and how you are flying. Those alternative behaviours will be initiated at loss of RC connection or Low battery level. You will be able to cancel them low battery level, but not at loss of RC connection. Most of those settings are accessible from “Advanced settings” tab in DJI Fly and Go apps.
- Home Point – this is the point to which your drone will return to when Failsafe kicks in. It can be set to Static or Dynamic. In Static state – drone will return to the point from which drone was launched). In Dynamic state it will return to the point where controller is at the time.
- RTH Altitude – the altitude at which the drone will return home. It should always be set to clear any trees, buildings or hills.
- RTH (Return To Home, also called Return To Launch) – in this state the drone will return IN A STRAIGHT LINE to the Home Point at the RTH Altitude. You will be able to adjust heading and altitude while in flight, but the drone will always continue on the shortest path (regardless of whether it’s facing the Home Point or not. Obstacle avoidance will be active (if supported by the flight mode and the drone. Not all drones have sideways obstacle avoidance, so if the drone is flying sideways, it may crash. This is why the RTH Altitude should be higher than any obstacles. This mode requires GPS to be active, otherwise the drone won’t know where it is and where “home” is.
- Autoland – the drone will land in current position. Unless you are flying in a very well known location and know for sure that you will be able to get to the drone, you will not want to use this feature. The drone will autoland anyway at the critical battery level. This is the lowest level failsafe, no GPS is required.
- Hover – the drone will stay in current position until it is reconnected with RC or until the battery reaches critical level. Then it will autoland. This is setting that should be used when flying low in parks and forests or under bridges. It prevents drone from crashing into objects above when Failsafe kicks in. You may also want to use it when flying in deep valleys and mountains. For precise hower, drone will need GPS signal. Without GPS, it will drift with wind.
There is no “best” failsafe. You need to know your location and know what risk is likely to affect you more. If you are flying under trees – RTH will likely cause your drone to crash, because it will go up and crash into the tree branches above. Similarly – if you are flying under the bridge. In those two examples Hover would be better.
If you are flying over water, you want to get to the ground as soon as possible. You will not want to waste time hovering. And most definitely you will not want the drone to autoland.
The autoland in any of the cases I know is the last resort as it will not really give you any benefits over Hover or Return To Home.
Let me know if I missed anything 🙂
*based on DJI drones – link to user manual of Fly App here