Lost Drones

[nicoatridge]

I have had three bad experiences with Mavic drones in three weeks and am a bit baffled, and nervous about continuing with drones.

All three experiences happened in Switzerland. I have flown Mavic drones all over the world, but all three bad experiences happened in Switzerland.

First was with a Mavic Pro in Basel. I was trying to manually land the drone when it decided to fly off in another direction and hit somebody. Thankfully they were sanguine about the experience, but I wasn't. What if it had them in the head?

Second time was in Vevey with RTH. It didn't return to home, it flew off in a random direction and last i saw of it looked like it hit a stairwell on top of a block of flats. $1000 dollars of drone gone.

So I bought a Mavic 2 Zoom. Fabulous drone, great footage. Went to Ventoux to take video lost with the last drone and after hovering for me to take a pic, the drone just shot off randomly and hit a building a few hundred metres away - so much for collision detection. I couldn't control it at all, just had to watch as it totalled itself. Landed on a balcony and haven't been able to retrieve it, so that's another $1200 down the toilet.

Am I just unlucky or what? Is there something in the air in Switzerland? I am totally giving up on flying drones for a while, not just the expense but the feeling that I can't control my drones and - frankly - it seems they represent a risk to public safety.

 

[PhantomPilotuk]

I would strongly consider taking up a hobby that doesn't involve flying with that kind of luck!

Joking apart that is terrible luck over a short space of time..

 

[Koelkop]

post the flight logs so Sar can tell you what happened

 

[Meta4]

I have had three bad experiences with Mavic drones in three weeks and am a bit baffled, and nervous about continuing with drones.

All three experiences happened in Switzerland. I have flown Mavic drones all over the world, but all three bad experiences happened in Switzerland.

First was with a Mavic Pro in Basel. I was trying to manually land the drone when it decided to fly off in another direction and hit somebody. Thankfully they were sanguine about the experience, but I wasn't. What if it had them in the head?

Second time was in Vevey with RTH. It didn't return to home, it flew off in a random direction and last i saw of it looked like it hit a stairwell on top of a block of flats. $1000 dollars of drone gone.

So I bought a Mavic 2 Zoom. Fabulous drone, great footage. Went to Ventoux to take video lost with the last drone and after hovering for me to take a pic, the drone just shot off randomly and hit a building a few hundred metres away - so much for collision detection. I couldn't control it at all, just had to watch as it totalled itself. Landed on a balcony and haven't been able to retrieve it, so that's another $1200 down the toilet.

Am I just unlucky or what? Is there something in the air in Switzerland? I am totally giving up on flying drones for a while, not just the expense but the feeling that I can't control my drones and - frankly - it seems they represent a risk to public safety.

Drones don't just fly off randomly, there's always a cause for the incident.
Your app has a "black box" data recorder and the recorded data will show what actually happened in these incidents.
If you want to learn what caused the issues and how to prevent them ....
Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

 

[nicoatridge]

Drones don't just fly off randomly, there's always a cause for the incident.
Your app has a "black box" data recorder and the recorded data will show what actually happened in these incidents.
If you want to learn what caused the issues and how to prevent them ....
Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

Thanks, that's useful. I can see the flight on my log, the drone just took off on a parabolic route into a distant building and seems to have ignored the sensors. I accept that there was an internal logic that made it do that, but it is clearly a bug for it to just go off and do that. I was hovering, took a photo, then whoosh...

 

[sar104]

Thanks, that's useful. I can see the flight on my log, the drone just took off on a parabolic route into a distant building and seems to have ignored the sensors. I accept that there was an internal logic that made it do that, but it is clearly a bug for it to just go off and do that. I was hovering, took a photo, then whoosh...

It's most unlikely that it was a bug. That kind of flight trajectory is generally caused by IMU/compass disagreements, although the M2 is much less prone to that. That error can be inferred from inertial calculations based on the data in the txt file, but direct evidence and the precise cause will be in the mobile device DAT file.

 

[charliesRig]

I have found with the M2P
In sports mode sensors turn off


... cR

 

[Meta4]

Thanks, that's useful. I can see the flight on my log, the drone just took off on a parabolic route into a distant building and seems to have ignored the sensors. I accept that there was an internal logic that made it do that, but it is clearly a bug for it to just go off and do that. I was hovering, took a photo, then whoosh...

There are some folks here that can read a lot more into the recorded flight data than you have.
Post the flight data for each of the problem flights if you would like to learn from those experiences.

The one you've mentioned sounds like it was due to the spot you launched from.
Can you describe the launch spot? (and please post the flight data)

 

[Racin8de]

I agree with the other guys, all three of your incidents the drones just flew away... Back in the earlier days with Phantoms it used to be a daily occurrence but hardly with the mavic.. I don't know if unknowingly doing something wrong, but if you post the logs you will get the exact cause... Sounds to me like your not giving the drone a min or 2 to record the home point or takeoff location.

 

[Meta4]

I agree with the other guys, all three of your incidents the drones just flew away... Back in the earlier days with Phantoms it used to be a daily occurrence but hardly with the mavic..

It's never been a daily occurrence.
There's no such thing as a "flyaway".

I don't know if unknowingly doing something wrong, but if you post the logs you will get the exact cause...
Sounds to me like your not giving the drone a min or 2 to record the home point or takeoff location.

You have to be very impatient to launch before recording a home point.
But if you did, the drone would acquire GPS very soon after launching and record a home point when it gets good GPS location data.
And that would not cause anything like what the OP described.

 

[Rogerc]

Very interested in the data logs.
Can’t wait to see what happened. We will all learn from this.

 

[nicoatridge]

Here is the flight log. The drone ascended vertically fine then just took over control and flew off without me doing anything, crashing a few hundred feet away. I managed to retrieve the drone, but nervous about flying it again unless I can work out what happened.

Flight time	Altitude​	Home Dist	Type	Notification
	00m 00s	0.0 ft	0 ft	Mode	Mode changed to P-GPS
	00m 00s	0.0 ft	0 ft	Warning	Compass Error
	00m 00s	0.0 ft	0 ft	Mode	Mode changed to Motors_Started
	00m 00s	0.0 ft	0 ft	Tip	Setting new Return-To-Home altitude to 30m (98 ft). Data Recorder File Index is 7. Setting new Maximum Flight Altitude to 30m (98 ft)
	00m 01s	0.0 ft	0 ft	Mode	Mode changed to Assisted_Takeoff
	00m 04s	0.0 ft	0 ft	Mode	Mode changed to P-GPS
	00m 04s	0.0 ft	0 ft	Warning	Braking now. Return sticks to midpoints, then continue flying.
	00m 07s	15.1 ft	0 ft	Warning	Maximum Flight Altitude Reached. Adjust altitude in MC Settings if required.
	00m 08s	16.7 ft	0 ft	Tip	Setting new Maximum Flight Altitude to 120m (394 ft)
A	00m 13s	62.7 ft	0 ft	Mode	Mode changed to P-GPS
B	00m 17s	71.5 ft	3 ft	Tip	Home Point recorded. Return-to-Home Altitude:30M
C	00m 23s	78.1 ft	276 ft	Warning	Not Enough Force/ESC Error (repeated 34 times)
	00m 27s	65.6 ft	499 ft		97% Battery at maximum distance

Drones don't just fly off randomly, there's always a cause for the incident.
Your app has a "black box" data recorder and the recorded data will show what actually happened in these incidents.
If you want to learn what caused the issues and how to prevent them ....
Go to DJI Flight Log Viewer | Phantom Help
Follow the instructions there to upload your flight record from your phone or tablet.
That will give you a detailed report on the flight data.
Come back and post a link to the report it gives you.

 

[nicoatridge]

Very interested in the data logs.
Can’t wait to see what happened. We will all learn from this.

Here's the story of the crash. It's a new drone. Worked fine on Saturday. Became possessed on Sunday...

 

[nicoatridge]

post the flight logs so Sar can tell you what happened

Done, thanks.

 

[Meta4]

Here's the story of the crash. It's a new drone. Worked fine on Saturday. Became possessed on Sunday...

Here's (a short version of) what your flight data really looks like: DJI Flight Log Viewer - PhantomHelp.com
It shows you launching without GPS or recording a home point (not necessarily a problem) and climbing to 22 metres before recording a home point at 0:17.3
At around 18 seconds you were hovering with hands-off and the drone started to pick up speed, flying a smooth curved track, accelerating to 25 metres/sec within seven seconds and the data stops.
It's going to require some deeper digging into the data but there are elements in the data that appear to show the effects of initialising the drone close to steel or perhaps live electrical cables.

Can you describe the spot you launched from please?

@sar104 ... here's one for your delicate touch

Do you have the .txt files from the two other flights you described?
They should be easier to solve.

 

[nicoatridge]

Thanks for that. I took off from a spot around twenty metres from a railway station on the shores of a lake surrounded by vineyards and a few buildings. I notice that the flight path overflew the overhead electric cables of the railway line, but I have overflown the same area with a Mavic Pro without incident. The Mavic 2 just seemed to get into a funk and sped off. It sounds like you think it may have been the overhead electric cables. If so, is there a recommended minimum height you should overfly them?

 

[DanMan32]

He didn't mean approaching overhead power lines, but rather electrical lines near takeoff, including underground.

Flying and approaching magnetic interference is a possible occurrence but much of the time the compass skew is created at launch.

Another possibility: are you storing your quads near magnetic fields such as speakers? Such items can cause the quad to be inappropriately magnetized. A degausser will fix that.

 

[Meta4]

Thanks for that. I took off from a spot around twenty metres from a railway station on the shores of a lake surrounded by vineyards and a few buildings. I notice that the flight path overflew the overhead electric cables of the railway line, but I have overflown the same area with a Mavic Pro without incident. The Mavic 2 just seemed to get into a funk and sped off. It sounds like you think it may have been the overhead electric cables. If so, is there a recommended minimum height you should overfly them?

I was particularly interested in the spot where you placed the drone to power it up.
Was it a reinforced concrete surface? Was it right beside a car or some structural steel work or a large pipe etc.
The behaviour exhibited by your drone is what happens when you power up the drone inside the magnetic field of some steel object.
The drone adjusts it's yaw value to match the distorted magnetic field and when it leaves that, the problems begin with a high speed circular path just as you observed.

 

[nicoatridge]

I was particularly interested in the spot where you placed the drone to power it up.
Was it a reinforced concrete surface? Was it right beside a car or some structural steel work or a large pipe etc.
The behaviour exhibited by your drone is what happens when you power up the drone inside the magnetic field of some steel object.
The drone adjusts it's yaw value to match the distorted magnetic field and when it leaves that, the problems begin with a high speed circular path just as you observed.

 

[nicoatridge]

Hi, the area I used for take-off was just an area of bitumen, away from nearby buildings, although relatively close to the power lines. I charge the drone battery near a speaker, but not adjacent.The take-off went as planned and I managed to take a shot I was after. The drone just then decided it was a question of seeing how fast it could crash.

After a previous incident, I am now really concerned about the risk of my drone hitting someone. I always aim to take off with no one within 50m, but if the drone does something erratic and - more worryingly ignores collision risk - it seems a threat to personal safety.

I found another flight record (with a Mavic Pro) that was one where I lost control of the drone during RTH where the drone repeatedly went away from the RTH point.

Regards, Nic