(Warning) Avoid this low battery RTH mistake

[Qoncussion]

***Before*** landing at a remote location, always set your RTH to hover or land (period). This ensures that what the OP describes will not happen.

 

[Yannie]

I read that OP landed somewhere other than the original take off point, so maybe the new landing spot was not the exact same elevation as take off point. So zero feet altitude shown on the display was in relation to the place he took off, and not the same as where he attempted to land which may have been -2 or -3 feet? Just a thought.

This is a good thought. It was very flat on both sides of the lake, with negligible difference in altitude. I didn't measure it though. But I definitely saw the drone settle onto the ground via the video.

Also, to answer a previous poster, I turned the controller off and this point and only turned it back on when I saw the drone up in the air again.

 

[Qoncussion]

That's really interesting...
Were you able to confirm whether or not the blades were still spinning while it was on the ground?

Easy - throttle up to see if the rotors are still engaged.

 

[Kilrah]

I read that OP landed somewhere other than the original take off point, so maybe the new landing spot was not the exact same elevation as take off point. So zero feet altitude shown on the display was in relation to the place he took off, and not the same as where he attempted to land which may have been -2 or -3 feet? Just a thought.

The aircraft doesn't care about the absolute altitude. As mentioned its "I'm on the ground" signal is expecting a commanded descent and not sensing the altitude diminish anymore for a few seconds, which explains the need to hold the throttle stick down for some time.

 

[joejaxvic123]

Yeesh, all of this stuff, I'd like to get an answer to the OP. I'm assuming the props were still turning, therefore the bird ( who thinks it is smarter than you are) took off to RTH at any cost. ?

 

[Yannie]

Easy - throttle up to see if the rotors are still engaged.

Sorry, perhaps my post wasn't clear. For the example you're referring to, did you know for sure whether or not the blades had stop spinning or not?

 

[Yannie]

This is proving to be quite an interesting topic. Later today I'll have a look at the flight logs. I'll also ascertain whether or not I capturer the last moments of this flight on video. I'll let you know what I find.

 

[Qoncussion]

Sorry, perhaps my post wasn't clear. For the example you're referring to, did you know for sure whether or not the blades had stop spinning or not?

To which I would again say that it is easy to ensure that the blades are not spinning, especially when landing at a remote location... Push the left stick up (throttle up) slightly to see through the video feed, or the telemetry info on the RC screen or in the app, if you gain altitude from the ground. No altitude gain? Props are not spinning.

 

[joejaxvic123]

I wonder about the RPM readout on the controller, I know there is a lot going on, and not noticing would be understandable. Will we be able to determine the drone didn't just start back up and take off to RTH?

 

[Qoncussion]

I wonder about the RPM readout on the controller, I know there is a lot going on, and not noticing would be understandable. Will we be able to determine the drone didn't just start back up and take off to RTH?

DJI drones never just start up, without a command from the RC, or the start of a waypoint mission. Reading the RPMs would have also been a good option.

 

[joejaxvic123]

So we can assume the unit was still running, props spinning, sitting on the ground, and it decided to take off to home point knowing the battery life might not get it back?

 

[rfc]

This is proving to be quite an interesting topic. Later today I'll have a look at the flight logs. I'll also ascertain whether or not I capturer the last moments of this flight on video. I'll let you know what I find.

Please post them. Better yet, upload the .dat files. Then we'll know for sure what happened.

 

[Snake2715]

Interesting thanks for posting and looking forward to what is found out.

 

[JMF]

There's something fishy here, if you landed it, then it shouldn't take off again, period.

 

[joejaxvic123]

There's something fishy here, if you landed it, then it shouldn't take off again, period.

You would think....but do you really know for sure?......

 

[Qoncussion]

There's something fishy here, if you landed it, then it shouldn't take off again, period.

So we can assume the unit was still running, props spinning, sitting on the ground, and it decided to take off to home point knowing the battery life might not get it back?

I'm guessing here, as this is not something I want to test - but, yeah - if the rotors are spinning, the Mavic is ready for flight. If the battery is above critical and the RC is turned off ~ then the proper action for it would be to follow the RTH protocol. Without one of the other two RTH options of either landing or hovering being selected - she's heading home.

 

[joejaxvic123]

We need a test here, Quoncussion said he would, ... .over a lake, way far away...lots of water around, could be interesting....I'm kinda nervous...

 

[kakao]

Still no definite answer ..

 

[Qoncussion]

We need a test here, Quoncussion said he would, ... .over a lake, way far away...lots of water around, could be interesting....I'm kinda nervous...

Don't forget - I'll also be at the end of a major runway. Yep... I'll get right on it!

In truth, I will try this out in a few days. It's really windy here today. But I know the perfect spot to try it out.

 

[joejaxvic123]

Cool. Thanks Qoncussion, I'm seriously interested.All joking aside.