Yesterday I had researched everything I could find on RTH. Then I went out to test it all out.
Admittedly I started what I thought was going to be a very short flight with 26% battery. I purposely flew it in a field, not far from me until it reached the 20% mark and forced a RTH. I was in Beginner Mode, with the RTH max height set for 30m and I was just under 30m from the drone when the forced RTH triggered and it was only at about 4m high in the air at the time.
Instead of returning and landing, or just landing where it was it rocketed straight up. I know what 30m looks like as I've taken it to that height before in Beginner Mode (which is the maximum height). This time it just kept going and going. After about 40 seconds I panicked and shut down RTH and tried to manually bring it down with the left stick down. Another minute or so went by and I'm at LOW, LOW battery and nothing. It went so high I couldn't see it nor even hear it. As the battery went to about 3% and no sign of it I thought I had lost it and suddenly I could hear it and it was coming down fast. I hit the left stick up and that slowed it considerably but it hit the ground without stopping, and hopped and kept flying. Luckily there was no damage as it landed on a grassy area. I reviewed the video and according to the face page of my Flight Record on the DJI GO 4 App, it went to 700 FEET!! The video seems to support this....it was incredibly high, almost in some clouds.
When I viewed the log later there are clearly some very strange readings including it showing a max IMU height of 60.7 feet but at the same time a VPS height of 10.5 feet. ???? There is no way it was only at 60.7 feet as the trees around me are all at least 100+ feet tall.
Then when I brought it down manually, it shows it finally stopped (hit the ground at a height of -90.2 feet (yes NEGATIVE 90.2 feet), which of course is impossible.
The flight log shows 2 "Speed Errors" and several "GPS Position NoMatch".
I checked Compass and IMU before launch and both were in the green.
The flight log and details are here: Airdata UAV - Flight Data Analysis for Drones
Another view with perhaps more information is here: DJI Flight Log Viewer - PhantomHelp.com
I'm pretty new to all this so I'd be grateful if anyone can explain how this happened. I was with my son at the time and we both nearly had heart attacks during that last 2 minutes or so.
Thank you to anyone who can perhaps tell me what went wrong here, as I'm pretty afraid to take it out again after this. The log shows it went from Beginner Mode to Go Home Mode once the forced RTH kicked in but what happened to the 30m ceiling? And what's with the 700 feet by itself and then landing -90 feet below the ground???
Admittedly I started what I thought was going to be a very short flight with 26% battery. I purposely flew it in a field, not far from me until it reached the 20% mark and forced a RTH. I was in Beginner Mode, with the RTH max height set for 30m and I was just under 30m from the drone when the forced RTH triggered and it was only at about 4m high in the air at the time.
Instead of returning and landing, or just landing where it was it rocketed straight up. I know what 30m looks like as I've taken it to that height before in Beginner Mode (which is the maximum height). This time it just kept going and going. After about 40 seconds I panicked and shut down RTH and tried to manually bring it down with the left stick down. Another minute or so went by and I'm at LOW, LOW battery and nothing. It went so high I couldn't see it nor even hear it. As the battery went to about 3% and no sign of it I thought I had lost it and suddenly I could hear it and it was coming down fast. I hit the left stick up and that slowed it considerably but it hit the ground without stopping, and hopped and kept flying. Luckily there was no damage as it landed on a grassy area. I reviewed the video and according to the face page of my Flight Record on the DJI GO 4 App, it went to 700 FEET!! The video seems to support this....it was incredibly high, almost in some clouds.
When I viewed the log later there are clearly some very strange readings including it showing a max IMU height of 60.7 feet but at the same time a VPS height of 10.5 feet. ???? There is no way it was only at 60.7 feet as the trees around me are all at least 100+ feet tall.
Then when I brought it down manually, it shows it finally stopped (hit the ground at a height of -90.2 feet (yes NEGATIVE 90.2 feet), which of course is impossible.
The flight log shows 2 "Speed Errors" and several "GPS Position NoMatch".
I checked Compass and IMU before launch and both were in the green.
The flight log and details are here: Airdata UAV - Flight Data Analysis for Drones
Another view with perhaps more information is here: DJI Flight Log Viewer - PhantomHelp.com
I'm pretty new to all this so I'd be grateful if anyone can explain how this happened. I was with my son at the time and we both nearly had heart attacks during that last 2 minutes or so.
Thank you to anyone who can perhaps tell me what went wrong here, as I'm pretty afraid to take it out again after this. The log shows it went from Beginner Mode to Go Home Mode once the forced RTH kicked in but what happened to the 30m ceiling? And what's with the 700 feet by itself and then landing -90 feet below the ground???
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