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RTH operation

jimlips

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A buddy of mine who is also a Mavic Pro Platinum owner took his MPP to the park to video his family reunion. When he arrived, he saw that his RC battery was only at 15% (the aircraft battery was completely charged). He decided to go ahead and do a very short flight, and do a panoramic shot. He was in Beginner mode for safety (he doesn't have much experience with the MPP), and the battery on his RC went from 15% to 0 in less than a minute.

His aircraft was pretty low, and when it lost the RC, the aircraft attempted to rise to RTH altitude, but kept bumping into tree branches. It finally was able to get to RTH altitude after colliding with several small branches. It flew back to the starting spot, but it did NOT descend and land. It just hovered there. He was able to borrow a friend's charger and plug his RC into it. When it got up to 1% charge, he turned it back on (still connected to the charger), regained control of the aircraft, and manually landed it. Good news is the only damage is a small chip out of one of the props.

My question: why didn't the aircraft land? Is this normal RTH operation, or should the aircraft have reduced altitude and continued to land? He said that part of the problem was there was a small "hole" in the tree cover where he took off from. Perhaps the downward sensors were preventing the aircraft from landing because it saw the trees as an obstacle?

The other problem was that he was videoing at the time the RC died, but when when the RC died, the aircraft stopped recording to the SD card. Is this also normal? He showed me the video, but it was missing the RTH part. It would have been interesting to see the video, but can't, because the recording was turned off when it lost RC.

Thank you for any info you can provide.
 

Irish-apple

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your { buddy } is very lucky he didnt hurt someone with the drone .. theres people here getting abuse for 80% battery etc and your buddy ! sent it up at 15%.
\
no words in fairness
 
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aokusman

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your { buddy } is very lucky he didnt hurt someone with the drone .. theres people here getting abuse for 80% battery etc and your buddy ! sent it up at 15%.
\
no words in fairness
I doubt the danger is over. His buddy still has the drone. 15 percent battery and launching show he really has not done his homework.
 
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netfolks2000

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One reason the drone may not have landed but just hovered is he may have the Failsave setting to just hover when controller signal is lost. That is what it sounds like. Did he check all those many settings before flying his drone? It is always risky to take off in a tiny clearance setting because if for any reason a Failsafe RTH is invoked the drone will be on its own trying to land between, as in his case, branches on either side.
 

jimlips

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It was set to Return To Home, not Hover. It came back to the takeoff area properly when the RC died, it just did not land. Does anyone have experience with this? Have you turned off your RC and seen if the drone would land on the ground after RTH? Just wondering...
 

sar104

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your { buddy } is very lucky he didnt hurt someone with the drone .. theres people here getting abuse for 80% battery etc and your buddy ! sent it up at 15%.
\
no words in fairness
Note that it appears it was the RC battery that was at 15%, not the aircraft battery. Still unwise, and indicated a lack of understanding of the RTH sequence.
 

sar104

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One reason the drone may not have landed but just hovered is he may have the Failsave setting to just hover when controller signal is lost. That is what it sounds like. Did he check all those many settings before flying his drone? It is always risky to take off in a tiny clearance setting because if for any reason a Failsafe RTH is invoked the drone will be on its own trying to land between, as in his case, branches on either side.
If it had been set to hover then it would not have ascended and returned to the home point - so that's not what happened. The vision sensors not seeing a clear landing area is more likely.
 

netfolks2000

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If it had been set to hover then it would not have ascended and returned to the home point - so that's not what happened. The vision sensors not seeing a clear landing area is more likely.
Many times they will come back to the home point and then wait for a command to come on down if they see the landing site as unsuitable due to what the sensors pick up. With the controller unavailable it appears it just kept waiting for the command to go down the last few feet perhaps.
 

sar104

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Many times they will come back to the home point and then wait for a command to come on down if they see the landing site as unsuitable due to what the sensors pick up. With the controller unavailable it appears it just kept waiting for the command to go down the last few feet perhaps.
That's my first guess, as I wrote above.
 

JY-tek

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Doesn't it give a warning, something like "unable to land safely" or something like that? I have seen something of the sort a couple of times when I tried to land in a windy condition.
 

mquinn1963

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Doesn't it give a warning, something like "unable to land safely" or something like that? I have seen something of the sort a couple of times when I tried to land in a windy condition.
Not to dwell on the fact that you should never attempt to fly if ANY battery is less than 50%, Several things here. First, when you start up your drone you need to wait for the GPS signals to get aquired and the HOME POINT is set and it says "home point updated" before taking off. 2nd the RTH function will bring the Drone back and then get close to the landing point but will send a message to the remote and wait for operator input before actually landing. My guess is that when the controller lost power it did not get that message and therefore wasnt able to give the final command. In this case when the controller was powered back on you were basically in manual mode. Maybe another push of the RTH button would have worked? But NEVER EVER fly without at least 50% power. GREAT lesson. I suggest a LOT of YOu tube videos before your friend flys much more.