Return-to-home over a campsite
You are flying a 1.2 kg drone in an open field at 110 m AGL, 400 m from you. Wind rises from 8 to 18 kt and the battery falls from 45% to 25% in two minutes. The drone's return-to-home altitude is set to 100 m. Between the drone and you is a temporary campsite with about 200 people; your home point is 50 m from the campsite edge. The drone is still controllable, but the controller warns 'strong wind' and the video feed stutters. Because of haze, you cannot see the drone unaided at 400 m.
1. What are the immediate hazards and why is the automated return-to-home setting a problem?
Read the worked answer
- The battery is falling quickly in rising wind, so the available energy margin is shrinking.
- Return-to-home is set to 100 m and the straight line to the home point crosses a campsite with about 200 people. Triggering it would route the drone over uninvolved people.
- In strong wind, return-to-home may not track the intended path accurately, may use more battery than expected, or may arrive with little reserve.
- You cannot see the drone unaided at 400 m because of haze, so visual line of sight is already compromised. Video stutter makes reliance on the feed worse.
- The home point is only 50 m from the campsite edge, so even an automatic landing could bring the aircraft close to people.
2. What action do you take now?
Read the worked answer
- Do not trigger return-to-home. Cancel it if it has started.
- The priority is to avoid the campsite and restore a safe situation. If you can still control the aircraft, manoeuvre it away from the campsite toward open ground and reduce height over that open ground.
- If you cannot regain unaided visual contact, land as soon as it is safe to do so in the open field, using the video feed only to confirm the landing area is clear. Do not continue the mission.
- Keep clear of people during the descent and do not attempt a long automatic return over the campsite.
- Once landed, do not relaunch in the same conditions; the wind and battery behaviour show the flight was already outside a comfortable margin.
3. What pre-flight settings and decisions would have prevented the conflict?
Read the worked answer
- Set the home point and return-to-home altitude so the automatic path avoids people, or fly from a location where the return path is over open ground.
- Identify emergency landing areas before take-off and brief when to use them instead of return-to-home.
- Check wind at altitude, not only at ground level, and set a lower wind limit for the aircraft and battery.
- Maintain visual line of sight; 400 m in haze was already too far for reliable unaided sight.
- Plan the flight so the aircraft stays within a battery reserve that accounts for wind, and abort early when the battery falls faster than planned.