RTH after turning remote off went to low and hit a tree

[Dronerman]

I make sure the RTH altitude is 80-100 before each flight. My colleague was flying the drone, it was reaching criticly low battery so he landed it after canceling the RTH. When he landed it he turned off the remote before turning off the drone less than a second after the drone had landed, even though i told him the remote is the first thing and last thing you turn on/off. The drone instantly turned back on, raised to about 15-20 m and tried to RTH straight into a tree, even though i had altitude set way higher than that. Does this mean if you turn off the remote and the aircraft is disconnected on dji go, the RTH altitude is lost and reset to default? or did it possibly do this because the smart RTH estimated it wouldnt have enough juice to raise to 100m and RTH?

Any way we recovered the drone and it was not damaged. He now understands why the remote should be last thing to turned off but thinks im being too an*l when i tell him not to turn the drone on before the remote, what are the dangers of turning on drone before the remote?

 

[Fly Dawg]

When he landed it he turned off the remote before turning off the drone less than a second after the drone had landed, even though i told him the remote is the first thing and last thing you turn on/off.

My question would be, was the drone shut down properly first. Primarily, shutting off the props. These should be done in,proper sequence to avoid such things as what you said occurred.

 

[Dronerman]

My question would be, was the drone shut down properly first. Primarily, shutting off the props. These should be done in,proper sequence to avoid such things as what you said occurred.

likely not, he turned off remote nearly instantly after landing

 

[Fly Dawg]

That would do it. Shutting off the props indicates end of flight, and there would be no takeoff following that step, unless manually done.

 

[Dronerman]

That would do it. Shutting off the props indicates end of flight, and there would be no takeoff following that step, unless manually done.

So is the RTH altitude and returns to default?

 

[Oso]

So is the RTH altitude and returns to default?

No, RTH does not reset itself to default when you turn off the RC.
Did you move from the HP or change the HP?

 

[Dronerman]

So it didnt raise to 100m because of the battery remaining?

 

[Fly Dawg]

So it didnt raise to 100m because of the battery remaining?

Correct, below critical battery causes auto land.

 

[Mark The Droner]

There was a similar thread on the other site about a week ago, but it was about a Mavic.

It's not clear what you meant when you say "reaching criticly low battery"

Did you reach it or did you not reach it? It matters. Assuming you didn't reach it...

On the P2 series ACs, if the AC is landed and the motors are turned off, AND the landing site is more than 20 meters from the home point, AND the controller is then turned off, the AC motors will start up on their own and begin RTH.

This doesn't happen with the Mavic, from what I've read. Turning off the motors ends the flight. No RTH regardless of what you do with the controller.

What happens with the P3? I'm not exactly sure. But from your description, it sounds like your AC went to RTH.

Re the RTH height, if the AC is in RTH and rising to minimum RTH height, and then if the controller is turned back on, and a stick is moved, the AC will abandon the rise to minimum RTH height and abruptly begin to fly to the home point, regardless of its height.

 

[dirtybum]

There was a similar thread on the other site about a week ago, but it was about a Mavic.

It's not clear what you meant when you say "reaching criticly low battery"

Did you reach it or did you not reach it? It matters. Assuming you didn't reach it...

(1)On the P2 series ACs, if the AC is landed and the motors are turned off, AND the landing site is more than 20 meters from the home point, AND the controller is then turned off, the AC motors will start up on their own



(2)the AC will abandon the rise to minimum RTH height and abruptly begin to fly to the home point.

I've actually never heard of either of these two scenarios! Are you sure Mark?

It seems if the r/c was shut off and the p3 was within 50' of controller/home point there would be no rth intentional or unintentional and if the p3 landed it would shut motors down. Are you absolutely sure of your "friends" actions or was it just his account of the story?

 

[Mark The Droner]

I can't say about a P3. My experience on this is with the P2. The OP seems to be describing an RTH scenario though.

But yes, I'm absolutely sure. I had heard about it long ago on a drone camps rc vid back in 2015, and then, sure enough, last spring I saw it with my own eyes. I was visiting a friend on a big flat lot with trees all around the perimeter. I flew north a bit, and then flew to the east. I had to walk south to get a good los connection with a gap in the trees. Then I brought it in and landed it in front of me a distance from home point, turned off the motors, but I was in conversation with my friend which messed me up. I turned my controller off first, which was my mistake. My P2 series AC actually restarted the motors as if it was possessed and started RTH all on its own. I had to turn my controller back on real quick and toggle my S1 switch to cancel RTH. Landed safely.
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I agree with you that if the AC is within 50' (actually within 20 meters) of home point, there would be no RTH. That's implied in the manual. Doesn't matter what model of AC.

 

[N017RW]

I can't corroborate MarkTDs report with specific experience but can say the P2, which is based on/contained a Naza V2 with unique f/w, did have some quirks.
But, that is a P2 not a P3S.

So could the P3 have inherited some P2 (Naza) 'tendencies'?
Could they have been corrected by an update and was the a/c 'current'?

Don't know.

 

[With The Birds]

I have read more than one account from a P3 owner that claimed the AC powered up and attempted RTh when landed and left idle away from the home point (presumably triggered by battery level). It was always something I planned to test. I have never powered down the RC before AC or powered the AC on before the RC, old habit from other RC models- very bad things could happen if you did things the other way around.

In any case the story isn’t making sense. If the AC has reaches critical battery it wouldn’t have taken off to perform RTh, the default action would be autoland which seemingly wouldn’t be necessary if it was already on the ground.

I would be getting the dat file off the AC and posting a link to it here I’m sure someone will look at it for you and tell you what actually happened.

 

[Mark The Droner]

It would help of the OP would answer the question - was the AC actually in critical battery, or was it "reaching" but did not actually reach critical battery?

Obviously if it was in critical battery, there would be no RTH.

Fourteen posts and nobody's thought to ask him to upload his log haha

OP please upload your log and paste the link: DJI Flight Log Viewer

site credit: msinger

 

[N017RW]

This is similar to what a P2 would do if left to idle on landing. It would the seemingly react to GPS drift and end up tilting-over due to landing gear dragging. It would not actually take-off.

As far as taking-off after a critical voltage landing, once landed the batt. drain is reduced and the voltage will recover. Possibly enough to 'cancel' the voltage induced critical level.

 

[With The Birds]

It would help of the OP would answer the question - was the AC actually in critical battery, or was it "reaching" but did not actually reach critical battery?

Obviously if it was in critical battery, there would be no RTH.

Fourteen posts and nobody's thought to ask him to upload his log haha

OP please upload your log and paste the link: DJI Flight Log Viewer

site credit: msinger

I suggested the .dat file might prove interesting- we shouldn’t expect to see the actual event in the log if the remote was shut down.

 

[Mark The Droner]

This is similar to what a P2 would do if left to idle on landing. It would the seemingly react to GPS drift and end up tilting-over due to landing gear dragging. It would not actually take-off.

Yes, but that's within the 20 meters. Outside the 20 meters, it would RTH. And it would do it quickly upon loss of control signal.

That is a good point though, re the P2 naza vs P3 non-naza FC.

I suggested the .dat file might prove interesting- we shouldn’t expect to see the actual event in the log if the remote was shut down.

oops you're right! I keep thinking of the P2 series...

 

[Dronerman]

It would help of the OP would answer the question - was the AC actually in critical battery, or was it "reaching" but did not actually reach critical battery?

Obviously if it was in critical battery, there would be no RTH.

Fourteen posts and nobody's thought to ask him to upload his log haha

OP please upload your log and paste the link: DJI Flight Log Viewer

site credit: msinger

Cant remember exactly as I wasn't flying the drone at the time, i'll grab the flight log from work on monday and upload it

 

[Dronerman]

I remember I was having trouble retrieving flight log off on the Ipad, i could export the photo of it but figure out how to export the actual file or csv

 

[solentlife]

" what are the dangers of turning on drone before the remote?"

Pretty well zero as the AC has not initialised with RC and has not flown. So it basically sits there 'dumb'. But it is against established sequential start where most RC is advised to be Controller first. (There are various micro drones such as some WLToys that drone first then controller ... but they are few).

RTH recorded settings. They remain until AC is fully powered down. BUT if the motors are stopped once landed - then AC should not initiate RTH if you switch of RC. But if motors have not been stopped and are idling on the ground - then RTH most likely will initiate if you switch off RC ... because the AC still thinks of itself in FLIGHT mode.

I am known for testing theories etc. - but this one I will not !! Having already paid dearly for testing another default parameter !!

Nigel