Peculiar fly-away

[AndrewVDP]

Hey guys. Not a regular here but I wanted to chime in on my experience today with the Mavic Pro and genuinely provide a warning instead of just complaining.

I lifted off today on a deserted beach in Maui to get some footage of the rocks on the coastline and my dear Mavic decided to just continue into the Abyss of the Pacific.

The gimbal was blown by the wind, so the camera very shortly after take off was facing downwards. At around 20m distance, I had no control anymore over which direction the aircraft was heading, just the altitude. It just continued flying around 4km until I was able to have her just hover and turn around. Return-to-home was able to be activated from the very beginning of this fiasco to no avail.

Transmission strength with the controller was stable and strong for the entire flight and a last ditch attempt to reboot the controller and attach a second phone with the DJI Go app was proved fruitless. I thus had to witness the demise of this drone into the Pacific ocean; something I feel guilty about contributing to polluting.

I'm really not sure if this is a firmware issue, sand inside of a motor, software or a list of other unforeseeable circumstances but we all need to keep an eye out. I'm kind of happy this was over the ocean and not a populated area.

P.s. I wouldn't call myself an experienced UAV pilot, but I do have around 590km of flight distance with this drone.

 

[macoman]

Just curious, what was the wind speed on that day that you lost your Mavic? Any wind over 25mph can be a dangerous situation for your Mavic to overcome.

 

[AndrewVDP]

Just curious, what was the wind speed on that day that you lost your Mavic? Any wind over 25mph can be a dangerous situation for your Mavic to overcome.

Between 13-16mph. This occured in a location that was less windy than a previous flight that day (today).

 

[Simmo]

Post your flight logs so we can see what happened and hopefully prevent it happening to anyone else.
Follow these instructions DJI Flight Log Viewer - Phantom Help
And post the link back here.

 

[Meta4]

I lifted off today on a deserted beach in Maui to get some footage of the rocks on the coastline and my dear Mavic decided to just continue into the Abyss of the Pacific.

I'm really not sure if this is a firmware issue, sand inside of a motor, software or a list of other unforeseeable circumstances but we all need to keep an eye out. I'm kind of happy this was over the ocean and not a populated area.

A lost drone is never good but it's worse when you can't tell why.
Your description doesn't give any good clues to help but there's a good chance the recorded flight data will either explain it or help eliminate some possible causes.
Go to DJI Flight Log Viewer - Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it provides and someone might be able to analyse it and give you an understanding of the cause of the incident.

 

[Zonian]

Hello Andrew, I just read your post; sorry for the loss of your Mavic.

I'm not an expert, there are others on here that can help you a lot.

But I am curious; I do not understand what does "The gimbal was blown by the wind, so the camera very shortly after take off was facing downwards" mean?

 

[kidroc]

yes please post your logs.. i'm guessing weak gps signal!!

 

[swings16]

Hello Andrew, I just read your post; sorry for the loss of your Mavic.

I'm not an expert, there are others on here that can help you a lot.

But I am curious; I do not understand what does "The gimbal was blown by the wind, so the camera very shortly after take off was facing downwards" mean?

...I too was puzzled by ....THE GIMBAL WAS BLOWN etc.

 

[Rick W]

Sorry about your loss. Any chance that water/moisture contributed to first the gimbal failing and then a critical electronics/control system failure on the drone? As the ocean strikes the rocks along the coast of Maui a significant amount of sea spray (along with sand) is often launched into the air. It may not have been visible from your distance. If this spray gets sucked into one of the cooling vents on the Mavic good things don't happen.

 

[sar104]

Sorry about your loss. Any chance that water/moisture contributed to first the gimbal failing and then a critical electronics/control system failure on the drone? As the ocean strikes the rocks along the coast of Maui a significant amount of sea spray (along with sand) is often launched into the air. It may not have been visible from your distance. If this spray gets sucked into one of the cooling vents on the Mavic good things don't happen.

Anything is possible, but when someone reports a gimbal being blown around and "13 - 16 mph" winds on the coast, the most obvious explanation is that the winds aloft were much stronger. If we ever see the flight log then the answer will likely become clear - until then there is little point speculating further.

 

[Jackcutrone]

Between 13-16mph. This occured in a location that was less windy than a previous flight that day (today).

If the wind at ground level was 13-16, the winds aloft are stronger and depending on altitude were likely to have exceeded or greatly exceeded 25 mph. Not to mention ifsustained winds are that strong gusts are likely and likely to be stronger.

Must admit your statement that the gimbal was blown by the wind in addition to being next to impossible or at least weird makes me think it was strong winds that did you in.

 

[Jackcutrone]

Anything is possible, but when someone reports a gimbal being blown around and "13 - 16 mph" winds on the coast, the most obvious explanation is that the winds aloft were much stronger. If we ever see the flight log then the answer will likely become clear - until then there is little point speculating further.

SAR104 posted his as I was writing my post. I agree with him.

 

[Zonian]

If the wind at ground level was 13-16, the winds aloft are stronger and depending on altitude we’re likely to have exceeded or greatly exceeded 25 mph. Not to mention ifsustained winds are that strong gusts are likely and likely to be stronger. ...

I have experienced this first hand.

 

[AndrewVDP]

Hey guys, thanks a lot for the replies.

I can't access my flight logs at this moment but will venture to get them up when I have access to a PC. I'm actually on holiday.

The wind gusts on sea are definitely an explanation that I could get onboard with and my initial reaction but I've flown in worse conditions (a very short and safe distance) in southern England, and also on the same day here in Maui further up the coast. It's just my gut telling me there was some other factor at play here.

Flight records should be able to give more insight and thanks!

edit: Got the flight record: DJI Flight Log Viewer - PhantomHelp.com

(There's a second flight record/continuation from after I rebooted the controller but it doesn't seem useful)

 

[idbl_fanatic]

This record stops while you are still 349 feet high, can you post the 2nd one as well? I see that there were a few high wind warnings

 

[AndrewVDP]

Sure,

Here it is: DJI Flight Log Viewer - PhantomHelp.com

 

[sar104]

Sure,

Here it is: DJI Flight Log Viewer - PhantomHelp.com

And here is your explanation:

 

[Meta4]

my dear Mavic decided to just continue into the Abyss of the Pacific.

Mavics usually don't decide to do anything.
They follow your instructions but can be affected by outside factors such as wind.

At around 20m distance, I had no control anymore over which direction the aircraft was heading, just the altitude.

That's not quite true. but it should have been a big clue to take note of before zooming off into the Pacific.
Your drone was responding to your joystick inputs. When you used the left stick to rotate, the Mavic rotated. When you pushed forward or back, the Mavic went forward or back as well as the wind would allow it to.
But the wind was substantial as can be seen early in your flight.
At 0:35.2 you initiated RTH.
The drone climbed to RTH height (30 metres) and was not able to hold position while climbing.
It was being blown further away at 2-5 metres/sec by gusty winds while the altitude was <30 metres.
After 0:54.3 when RTH started flying towards home, the speed it was being blown backwards slowed to 1 m/s @ 30 metres but you cancelled RTH at 1:04 with the drone 234 metres away.

At that point, you could have recovered the Mavic - if you had disabled obstacle avoidance, lowered the drone and flown back manually.
But you didn't.
Instead, you left OA on and tried to fly east and then west, all the while being blown further to the SSW at 5+ m/s.
You let it coast, tried RTH again and doodled around a bit, all the time getting blown further away at 5-7 m/s.
At 4:42, you decided to climb higher ???
That's never going to help since the winds higher up are always going to be stronger.

Eventually you ended up 2.6 km out, at 106 metres altitude, being blown backwards at 5-7 m/s in slow RTH and the battery at 28%.
We don't need to see the second flight record to tell how this ended.

Transmission strength with the controller was stable and strong for the entire flight and a last ditch attempt to reboot the controller and attach a second phone with the DJI Go app was proved fruitless.

There was only one problem (being blown away in a strong wind).
I'm not sure how you thought changing phones would make any difference. (the words deckchairs and Titanic come to mind)

I'm really not sure if this is a firmware issue, sand inside of a motor, software or a list of other unforeseeable circumstances but we all need to keep an eye out.
P.s. I wouldn't call myself an experienced UAV pilot, but I do have around 590km of flight distance with this drone.

Instead of unseen mystery problems, we really need to be aware of the obvious issues in the local environment.
And wind is a big one.
You can feel it on your face and hear it on your ears.
That gives you an idea of its strength and direction.
Launching in a strong wind and flying downwind is always a losing strategy. Going further and higher only makes things worse.
RTH is a slow driver and flies slower than you can when you do the driving.
Obstacle Avoidance also slows the drone.

The short lesson from this is:
If the drone can't hold position because of the wind, you are going to have a strong wind situation that is likely to cause problems.
Rule 1. Never fly away downwind in a strong wind

 

[Aerobatty]

Between 13-16mph. This occured in a location that was less windy than a previous flight that day (today).

Was the wind Onshore or off?

 

[AndrewVDP]

Was the wind Onshore or off?

That was onshore, according to weather data.

I think @Meta4 was pretty spot-on, though I still think I lost control around shoreline, making the mistake in believing my hovering on the beach before making flight was a good enough indicator for flying over the water in terms of wind.

Anyways, thanks to @Meta4 (& @sar104 ) for the blunt analysis of the logs I posted. It's a hard lesson that will come in handy when I replace the drone when I'm back on the mainland.