This is a copy and paste of a thread I posted in another forum.
I almost lost my Mavic this evening. The wind was calm to almost non existent on the ground level, so I thought: well, it's a good early evening to do some long distance flight. I did not even bother to check UAV Forecast as there was practically no wind at the ground level.
After the usual take off from the balcony and landed on a small clearing in front of the balcony to get GPS lock and to set Home Point, I started the flight with battery level of about 96%. Nothing unusual about the flight. Cruising along at 150m high (legal limit in my country), the Mavic rarely touch 50kph so I didn't think that I was having tailwind (never do longish flight with tailwind!). Smart RTH kicked in just before I reached 5km with 67% battery remaining. Nothing unusual, I have done this many, many times.
I've set the Mavic RTH speed at 48 kph, so with muted RTH beeps, I can have a relaxing RTH flight. This time, the Mavic barely got 30kph. Immediately I knew I was in trouble. Pushing the right stick forward didn't help at all as I've set it close to it's max speed under GPS mode with OA off. Switched to Sports mode did increase the speed somewhat and I used this mode for a while. But then I thought as I was still more than 4.6km away and the Mavic was still going "reasonably" fast, Sports mode was probably not a good idea. So I switched back to normal mode. When it reached 4km away from HP, I lowered the height to 120m. Didn't help any, so I lowered it even further to 100m. Not a difference. And it was still 3.5km away. My heart was pounding and I started to curse. I knew I was in deep trouble. Lowered it even further to 90m high, still no difference. And it was still over 3km away. Lowered it even further to 80m, still no difference. Cannot lower it further as I started to lose connection and there were rather tall buildings to the left and right of the path. Brought it back up to 90m. 25% battery remaining and it was still 1.8km away! I thought I would certainly lose it as it won't make it back home. Once it reached 25%, the battery seemed to drop faster!
I lived in an urban jungle, if the Mavic landed somewhere on the street or on people's property, I might as well kiss it good bye. 900m away from HP and it started to pick up speed, reaching a bit over 40kph. 600m away and the battery was at critical level and the Mavic started to autoland. As I have mentioned in several threads, Safer Autoland didn't work for me. To make things worse, to cancel the autoland I switched to Sports mode, but in panic forgot to return it back to normal mode, so the Mavic did not respond smoothly with joysticks input. Pounding heartbeat didn't help either. I had to fight it from landing and it was still 600+m away! By this time RTH didn't work as it already attempted to land, so I have to control it manually with that jerky joystick response. While kept on pushing the right stick forward, I let the altitude to drop. At that time I thought (wrongly as I was in panic) that it's better to let it fall from lower altitude than high, higher chance of survival. Then finally...with 7% battery level remaining I managed to get it above the small plot of land in front of my balcony. Right there it started to land, could not force it to go up anymore. It was also already too dark for me to visually brought it to the smooth surface I "dedicated" for it to land, but at least it's somewhere I can get it! It finally landed on a rocky uneven surface with 5% battery remaining. Nicked one of the prop slightly as it hit some rocks. Not needed to be replaced though as it was very minor damage. Considering that I almost lost the drone, it was really nothing!
Now, if only Safer Autoland works, I would probably be a little bit calmer and can manage to land it at its designated landing place. Another lesson learnt? Even if the surface wind is almost non existant, I will always check UAV Forecast before attempting a long distance flight. The wind up there and 4-5km away can be very different and can caught us by surprise. Checking UAV Forecast later showed that on the return flight I had sideway headwind with gusts of 35kph!
I almost lost my Mavic this evening. The wind was calm to almost non existent on the ground level, so I thought: well, it's a good early evening to do some long distance flight. I did not even bother to check UAV Forecast as there was practically no wind at the ground level.
After the usual take off from the balcony and landed on a small clearing in front of the balcony to get GPS lock and to set Home Point, I started the flight with battery level of about 96%. Nothing unusual about the flight. Cruising along at 150m high (legal limit in my country), the Mavic rarely touch 50kph so I didn't think that I was having tailwind (never do longish flight with tailwind!). Smart RTH kicked in just before I reached 5km with 67% battery remaining. Nothing unusual, I have done this many, many times.
I've set the Mavic RTH speed at 48 kph, so with muted RTH beeps, I can have a relaxing RTH flight. This time, the Mavic barely got 30kph. Immediately I knew I was in trouble. Pushing the right stick forward didn't help at all as I've set it close to it's max speed under GPS mode with OA off. Switched to Sports mode did increase the speed somewhat and I used this mode for a while. But then I thought as I was still more than 4.6km away and the Mavic was still going "reasonably" fast, Sports mode was probably not a good idea. So I switched back to normal mode. When it reached 4km away from HP, I lowered the height to 120m. Didn't help any, so I lowered it even further to 100m. Not a difference. And it was still 3.5km away. My heart was pounding and I started to curse. I knew I was in deep trouble. Lowered it even further to 90m high, still no difference. And it was still over 3km away. Lowered it even further to 80m, still no difference. Cannot lower it further as I started to lose connection and there were rather tall buildings to the left and right of the path. Brought it back up to 90m. 25% battery remaining and it was still 1.8km away! I thought I would certainly lose it as it won't make it back home. Once it reached 25%, the battery seemed to drop faster!
I lived in an urban jungle, if the Mavic landed somewhere on the street or on people's property, I might as well kiss it good bye. 900m away from HP and it started to pick up speed, reaching a bit over 40kph. 600m away and the battery was at critical level and the Mavic started to autoland. As I have mentioned in several threads, Safer Autoland didn't work for me. To make things worse, to cancel the autoland I switched to Sports mode, but in panic forgot to return it back to normal mode, so the Mavic did not respond smoothly with joysticks input. Pounding heartbeat didn't help either. I had to fight it from landing and it was still 600+m away! By this time RTH didn't work as it already attempted to land, so I have to control it manually with that jerky joystick response. While kept on pushing the right stick forward, I let the altitude to drop. At that time I thought (wrongly as I was in panic) that it's better to let it fall from lower altitude than high, higher chance of survival. Then finally...with 7% battery level remaining I managed to get it above the small plot of land in front of my balcony. Right there it started to land, could not force it to go up anymore. It was also already too dark for me to visually brought it to the smooth surface I "dedicated" for it to land, but at least it's somewhere I can get it! It finally landed on a rocky uneven surface with 5% battery remaining. Nicked one of the prop slightly as it hit some rocks. Not needed to be replaced though as it was very minor damage. Considering that I almost lost the drone, it was really nothing!
Now, if only Safer Autoland works, I would probably be a little bit calmer and can manage to land it at its designated landing place. Another lesson learnt? Even if the surface wind is almost non existant, I will always check UAV Forecast before attempting a long distance flight. The wind up there and 4-5km away can be very different and can caught us by surprise. Checking UAV Forecast later showed that on the return flight I had sideway headwind with gusts of 35kph!
